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  • CLASSES

    Cyclo-oxygenase Inhibitor Platelet Aggregation Inhibitors

    DEA CLASS

    Rx

    DESCRIPTION

    Combination antiplatelet agent and proton pump inhibitor
    Used for patients who require aspirin for secondary prevention of cardiovascular and cerebrovascular events and who are at risk of developing aspirin-associated gastric ulcers
    Not intended for the initial dose of aspirin therapy during onset of acute coronary syndrome, acute myocardial infarction, or before percutaneous coronary intervention

    COMMON BRAND NAMES

    Yosprala

    HOW SUPPLIED

    Yosprala Oral Tab DR: 325-40mg, 81-40mg

    DOSAGE & INDICATIONS

    For the reduction of cardiovascular mortality and prevention of secondary cardiovascular and cerebrovascular events (e.g., myocardial infarction prophylaxis, stroke prophylaxis) in patients at risk for aspirin associated gastric ulcers and also have a history of stroke, TIA, myocardial infarction, angina (including unstable angina), or are post cardiac surgery (CABG, PTCA).
    Oral dosage
    Adults

    81 mg aspirin; 40 mg omeprazole or 325 mg aspirin; 40 mg omeprazole PO daily. This combination product is not intended for use as the initial dose of aspirin during the onset of acute coronary syndrome, acute myocardial infarction or before percutaneous coronary intervention. Aspirin; omeprazole has not been shown to reduce the risk of gastrointestinal bleeding due to aspirin. Generally, 81 mg of aspirin is an effective dose for secondary cardiovascular prevention. The combination product is not interchangeable with the individual components of aspirin and omeprazole.

    MAXIMUM DOSAGE

    Adults

    325 mg aspirin; 40 mg omeprazole.

    Geriatric

    325 mg aspirin; 40 mg omeprazole.

    Adolescents

    Safety and efficacy have not been established.

    Children

    Safety and efficacy have not been established.

    Infants

    Safety and efficacy have not been established.

    Neonates

    Safety and efficacy have not been established.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    Avoid aspirin; omeprazole in patients with any degree of hepatic impairment.

    Renal Impairment

    CrCl >= 10 mL/min: No dosage adjustment required.
    CrCl < 10 mL/min: Avoid use.

    ADMINISTRATION

    Oral Administration
    Oral Solid Formulations

    Administer at least 60 minutes before a meal.
    Swallow whole with liquid. Do not split, crush, or dissolve the tablet.

    STORAGE

    Yosprala:
    - Protect from moisture
    - Store at 77 degrees F; excursions permitted to 59-86 degrees F
    - Store in original container

    CONTRAINDICATIONS / PRECAUTIONS

    General Information

    Gastric acid suppression may increase serum chromogranin A (CgA). Increased CgA concentrations may cause false positive results in diagnostic investigations for neuroendocrine tumors. Clinicians should temporarily stop aspirin; omeprazole 14 days before assessing CgA levels and consider repeating the test if initial CgA levels are high. If serial tests are performed (e.g. for monitoring), the same commercial laboratory should be used for testing, as reference ranges between tests may vary.

    NSAID hypersensitivity, salicylate hypersensitivity

    Aspirin; omeprazole is contraindicated in patients with a known hypersensitivity to omeprazole, substituted benzimidazoles, salicylate hypersensitivity, NSAID hypersensitivity, or to any of the excipients in the formulation. It is also contraindicated in patients with the syndrome of asthma, rhinitis, and nasal polyps; aspirin my cause severe urticaria, angioedema, or bronchospasm (asthma). 

    Children, viral infection

    Aspirin; omeprazole is contraindicated in pediatric patients with a suspected viral infection, with or without fever, because of the risk of Reye's syndrome with concomitant use of aspirin in certain viral illnesses. Furthermore, the safety and efficacy of aspirin; omeprazole has not been established in children.

    Labor, obstetric delivery, pregnancy

    Avoid aspirin; omeprazole in pregnant women starting at 30 weeks gestation (third trimester). The use of NSAIDs, including aspirin, during the third trimester of pregnancy increases the risk of premature closure of the fetal ductus arteriosus. Available data involving aspirin use during pregnancy do not demonstrate a clear association with major birth defects or risk of miscarriage. Maternal aspirin use during the third trimester may increase the risk of neonatal complications including necrotizing enterocolitis, patent ductus arteriosus, intracranial hemorrhage in premature infants, low birth weight, stillbirth, and neonatal death. In addition, NSAIDS, including aspirin, may increase the risk of complications during labor or obstetric delivery and to the neonate. Aspirin should be avoided 1 week prior to and during labor and delivery as use can result in excessive blood loss at delivery. Data involving the use of omeprazole during pregnancy have not demonstrated a clear association with major birth defects or risk of miscarriage. Animal reproduction studies resulted in dose-dependent embryo-lethality at omeprazole doses that were approximately 2.4 to 34 times an oral human dose of 40 mg. Changes in bone morphology were observed in offspring of rats receiving doses equal to or greater than 34 times an oral human dose of 40 mg.

    Breast-feeding

    Aspirin and omeprazole are present in human milk. Limited data state the presence of aspirin in human milk at relative infant doses of 12.5% to 10.8% of the maternal weight-adjusted dosage. There are published case reports of breast-feeding infants whose mothers were exposed to aspirin during lactation developing metabolic acidosis, thrombocytopenia, and hemolysis. There are no data on the effect of aspirin on milk production. Limited data from a case report describes the presence of omeprazole in human milk at a relative infant dose of 0.9% of the maternal weight-adjusted dosage. There are not reports of adverse effects of omeprazole on the breastfed infant and no information on the effects of omeprazole on milk production. Due to the potential for serious adverse reactions, including metabolic acidosis, thrombocytopenia, hemolysis, or Reye's syndrome, advise patients that breast-feeding is not recommended during treatment with aspirin; omeprazole.

    Abrupt discontinuation

    Avoid abrupt discontinuation of aspirin; omeprazole as this could increase the risk of myocardial infarction or stroke.

    Coagulopathy, hemophilia, vitamin K deficiency

    Since even low doses of aspiring can inhibit platelet aggregation and increase bleeding time, aspirin should be used cautiously in patients with coagulopathy, hemophilia, or acquired bleeding disorders such as liver disease or vitamin K deficiency. Monitor patients for signs of bleeding.

    Gastritis, GI bleeding

    Asprin use is associated with serious gastrointestinal adverse reactions including gastritis and GI bleeding. Although the omeprazole component of aspirin; omeprazole is indicated for decreasing the risk of developing aspirin-associated gastric ulcers in patients at risk for developing aspirin-associated gastric ulcers due to age (>= 55 years) or documented history or gastric ulcers, aspirin; omeprazole has not been shown to reduce the risk of GI bleeding due to aspirin. All patients should be monitored for signs of ulceration and bleeding, even in the absence of previous GI symptoms. If active and clinically significant bleeding from any source occurs during aspirin; omeprazole therapy, discontinue treatment.

    Alcoholism

    Use aspirin; omeprazole cautiously in patients with alcoholism. Patients who consume 3 or more alcoholic drinks every day should be counseled about the bleeding risk with chronic, heavy alcohol use while taking aspirin; omeprazole.

    Renal failure

    Avoid aspirin; omeprazole use in patients with severe renal failure (CrCl < 10 mL/minute). In patients with pre-existing renal disease, aspirin use decreases glomerular filtration rate and renal blood flow. The regular use of aspirin is associated with a dose-dependent increased risk of chronic renal failure.

    Gastric cancer

    Symptomatic response to therapy with aspirin; omeprazole does not preclude the presence of gastric cancer. Omeprazole decreases intragastric acidity. Subsequently, the number of bacteria in gastric secretions and, correspondingly, the amount of carcinogenic N-nitroso compounds produced by these bacteria increase. The overall risk of carcinoid tumors during therapy with proton pump inhibitors (PPI) is low based on cumulative safety experience. Consider additional gastrointestinal diagnostic testing in patients who experience gastric symptoms during treatment with aspirin; omeprazole or in those patients who have a symptomatic relapse after completing treatment. In older patients, consider endoscopy.

    Diarrhea

    Proton pump inhibitor (PPIs) therapy like aspirin; omeprazole has been linked to an increased risk of Clostridium difficile–associated diarrhea (CDAD), especially in hospitalized patients. A diagnosis of CDAD should be considered for patients taking PPIs who develop diarrhea that does not improve. Advise patients to seek immediate care from a healthcare professional if they experience watery stool that does not go away, abdominal pain, and fever while taking PPIs. Patients should use the lowest dose and shortest duration of PPI therapy appropriate to the condition being treated.

    Osteoporosis

    Use proton pump inhibitors (PPIs) like aspirin; omeprazole in patients with or who have risk factors for osteoporosis cautiously. PPIs have been associated with a possible increased risk of bone fractures of the hip, wrist, and spine. The risk of fracture was increased in patients who received high-dose (defined as multiple daily doses or doses greater than those recommended in non-prescription use), and long-term PPI therapy (a year or longer); fractures were primarily observed in older adult and geriatric patients 50 years of age and older. Use the shortest duration of aspirin; omeprazole therapy appropriate to the condition being treated. In patients with or at risk for osteopenia or osteoporosis, manage their bone status according to current clinical practice, and ensure adequate vitamin D and calcium supplementation. According to the Beers Criteria, PPIs are considered potentially inappropriate medications (PIMs) for use in geriatric patients due to the risk of Clostridium difficile and bone loss/fractures. Scheduled use for more than 8 weeks should be avoided except for high-risk patients (e.g., oral corticosteroids or chronic NSAID use), erosive esophagitis, Barrett's esophagitis, pathological hypersecretory condition, or demonstrated need for maintenance treatment (e.g., due to failure of drug discontinuation trial or H2 blockers).

    Vitamin B12 deficiency

    Daily treatment with gastric acid-suppressing medication such as aspirin; omeprazole over a long period of time (e.g., longer than 3 years) may lead to malabsorption of cyanocobalamin and vitamin B12 deficiency. Rare reports of vitamin B12 deficiency occurring with acid-suppressing therapy have been reported in the literature. The possibility of vitamin B12 deficiency should, therefore, be considered if clinical symptoms are observed.

    Geriatric

    During clinical trials of aspirin; omeprazole, 62% of patients were older than 65 and 15% were 75 years and older. No difference in safety or efficacy was observed between older and younger patients. According to the Beers Criteria, PPIs such as omeprazole are considered potentially inappropriate medications (PIMs) for use in geriatric patients due to the risk of Clostridium difficile and bone loss/fractures. Scheduled use for more than 8 weeks should be avoided except for high-risk patients (e.g., oral corticosteroids or chronic NSAID use), erosive esophagitis, Barrett's esophagitis, pathological hypersecretory condition, or demonstrated need for maintenance treatment (e.g., due to failure of drug discontinuation trial or H-2 blockers). In addition, the Panel considers aspirin to be a PIM in geriatric patients. Aspirin may cause new or worsening gastric or duodenal ulcers and there is an increased risk of GI bleeding and peptic ulcer disease in high risk groups including those above 75 years of age, or those taking oral or parenteral corticosteroids, anticoagulants, or antiplatelet medications. Therefore, the Beers expert panel recommends avoiding chronic use of aspirin doses above 325 mg/day in high risk patients, unless other alternatives are not effective and a gastro-protective agent can be used. In addition, aspirin doses above 325 mg/day should be avoided in patients with a history of gastric or duodenal ulcers, unless other alternatives are not effective and a gastro-protective agent can be used. It should be noted that the use of a gastro-protective agent, like a proton-pump inhibitor or misoprostol reduces, but does not eliminate, GI risks. The Panel also recommends avoiding aspirin in geriatric patients with the following disease states or symptoms due to the potential for exacerbation of the condition or increased risk of adverse effects: heart failure (potential to promote fluid retention and exacerbate the condition) or chronic kidney disease Stage IV or less (CrCl less than 30 mL/min) (may increase the risk of acute kidney injury and cause a further decline of renal function). The risk of ulcers, gross bleeding, or perforation is cumulative with continued use (i.e., 1% of patients treated for 3 to 6 months and 2% to 4% of patients treated for 1 year); these trends continue with a longer duration of use.

    Systemic lupus erythematosus (SLE)

    Cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE) have been reported in patients taking proton pump inhibitors (PPIs), including omeprazole. Reports include new onset and exacerbations of existing disease. The majority of PPI-induced lupus erythematosus cases have been CLE. PPI-associated SLE is usually milder than non-drug induced SLE. Although onset of SLE typically occurred within 30 days of initiating PPI therapy, some cases occurred days or years after initiating treatment. SLE occurred primarily in older patients; however, cases have been reported in younger patients. Most patients present with a rash; however, arthralgia and cytopenia also have been reported. Antibody testing for lupus may be positive. Clinical signs and symptoms of SLE associated with PPI use are usually reversible upon discontinuation of the PPI. Most patients improve with discontinuation of the PPI alone in 4 to 12 weeks. Elevated serological tests may take longer to normalize. Avoid administration of PPIs for longer than medically indicated. If signs or symptoms of CLE or SLE are seen in patients taking aspirin; omeprazole, discontinue treatment and refer the patient to an appropriate specialist for evaluation.

    Hepatic disease

    Avoid aspirin; omeprazole in patients with severe hepatic disease. Long-term moderate to high doses of aspirin may result in elevations of serum ALT concentrations. These hepatic abnormalities typically resolve with discontinuation of aspirin therapy. The hepatotoxicity associated with aspirin is mild and asymptomatic. Bilirubin elevations are typically mild or absent. The systemic exposure to omeprazole is elevated in patients with hepatic impairment.

    Hypomagnesemia

    Daily treatment with a gastric acid-suppressing medication over a long period of time (e.g., 3 months to > 1 year) may lead to hypomagnesemia; cases have been reported in patients taking omeprazole. Generally, hypomagnesemia is corrected with magnesium supplementation; however, in cases where hypomagnesemia is observed during proton pump inhibitor (PPI) administration, discontinuation of the PPI may also be necessary. Low serum magnesium may lead to serious adverse events such as muscle spasm (tetany), seizures, and irregular heartbeat (arrhythmias). For patients expected to be on PPI therapy for a prolonged period of time, it is prudent for clinicians to obtain serum magnesium concentrations prior to initiating PPI therapy as well as throughout treatment. Patients on concomitant medications such as digoxin or diuretics may also require periodic monitoring of serum magnesium.

    ADVERSE REACTIONS

    Severe

    peptic ulcer / Delayed / Incidence not known
    GI perforation / Delayed / Incidence not known
    GI obstruction / Delayed / Incidence not known
    GI bleeding / Delayed / Incidence not known
    pancreatitis / Delayed / Incidence not known
    hepatic encephalopathy / Delayed / Incidence not known
    hepatic necrosis / Delayed / Incidence not known
    hepatic failure / Delayed / Incidence not known
    bradycardia / Rapid / Incidence not known
    cerebral edema / Early / Incidence not known
    seizures / Delayed / Incidence not known
    coma / Early / Incidence not known
    intracranial bleeding / Delayed / Incidence not known
    coagulopathy / Delayed / Incidence not known
    pancytopenia / Delayed / Incidence not known
    agranulocytosis / Delayed / Incidence not known
    hemolytic anemia / Delayed / Incidence not known
    disseminated intravascular coagulation (DIC) / Delayed / Incidence not known
    Stevens-Johnson syndrome / Delayed / Incidence not known
    toxic epidermal necrolysis / Delayed / Incidence not known
    lupus-like symptoms / Delayed / Incidence not known
    bronchospasm / Rapid / Incidence not known
    anaphylactoid reactions / Rapid / Incidence not known
    anaphylactic shock / Rapid / Incidence not known
    angioedema / Rapid / Incidence not known
    erythema multiforme / Delayed / Incidence not known
    laryngeal edema / Rapid / Incidence not known
    rhabdomyolysis / Delayed / Incidence not known
    bone fractures / Delayed / Incidence not known
    pulmonary edema / Early / Incidence not known
    optic atrophy / Delayed / Incidence not known
    optic neuritis / Delayed / Incidence not known
    hearing loss / Delayed / Incidence not known
    interstitial nephritis / Delayed / Incidence not known
    renal papillary necrosis / Delayed / Incidence not known
    renal failure (unspecified) / Delayed / Incidence not known

    Moderate

    gastritis / Delayed / 18.0-18.0
    stomatitis / Delayed / Incidence not known
    candidiasis / Delayed / Incidence not known
    colitis / Delayed / Incidence not known
    elevated hepatic enzymes / Delayed / Incidence not known
    hepatitis / Delayed / Incidence not known
    cholestasis / Delayed / Incidence not known
    jaundice / Delayed / Incidence not known
    sinus tachycardia / Rapid / Incidence not known
    angina / Early / Incidence not known
    chest pain (unspecified) / Early / Incidence not known
    hypertension / Early / Incidence not known
    palpitations / Early / Incidence not known
    hypotension / Rapid / Incidence not known
    peripheral edema / Delayed / Incidence not known
    depression / Delayed / Incidence not known
    confusion / Early / Incidence not known
    hallucinations / Early / Incidence not known
    hostility / Early / Incidence not known
    neutropenia / Delayed / Incidence not known
    prolonged bleeding time / Delayed / Incidence not known
    anemia / Delayed / Incidence not known
    thrombocytopenia / Delayed / Incidence not known
    leukopenia / Delayed / Incidence not known
    myasthenia / Delayed / Incidence not known
    hyponatremia / Delayed / Incidence not known
    hypomagnesemia / Delayed / Incidence not known
    hypokalemia / Delayed / Incidence not known
    hypoglycemia / Early / Incidence not known
    dehydration / Delayed / Incidence not known
    hyperglycemia / Delayed / Incidence not known
    hypocalcemia / Delayed / Incidence not known
    metabolic acidosis / Delayed / Incidence not known
    tachypnea / Early / Incidence not known
    blurred vision / Early / Incidence not known
    glycosuria / Early / Incidence not known
    proteinuria / Delayed / Incidence not known
    pyuria / Delayed / Incidence not known
    hematuria / Delayed / Incidence not known

    Mild

    nausea / Early / 3.0-3.0
    diarrhea / Early / 3.0-3.0
    gastric polyps / Delayed / 2.0-2.0
    anorexia / Delayed / Incidence not known
    vomiting / Early / Incidence not known
    xerostomia / Early / Incidence not known
    dyspepsia / Early / Incidence not known
    abdominal pain / Early / Incidence not known
    stool discoloration / Delayed / Incidence not known
    anxiety / Delayed / Incidence not known
    vertigo / Early / Incidence not known
    lethargy / Early / Incidence not known
    insomnia / Early / Incidence not known
    paresthesias / Delayed / Incidence not known
    drowsiness / Early / Incidence not known
    agitation / Early / Incidence not known
    dizziness / Early / Incidence not known
    abnormal dreams / Early / Incidence not known
    headache / Early / Incidence not known
    tremor / Early / Incidence not known
    leukocytosis / Delayed / Incidence not known
    xerosis / Delayed / Incidence not known
    photosensitivity / Delayed / Incidence not known
    rash (unspecified) / Early / Incidence not known
    purpura / Delayed / Incidence not known
    hyperhidrosis / Delayed / Incidence not known
    urticaria / Rapid / Incidence not known
    petechiae / Delayed / Incidence not known
    alopecia / Delayed / Incidence not known
    pruritus / Rapid / Incidence not known
    myalgia / Early / Incidence not known
    muscle cramps / Delayed / Incidence not known
    musculoskeletal pain / Early / Incidence not known
    arthralgia / Delayed / Incidence not known
    weight gain / Delayed / Incidence not known
    epistaxis / Delayed / Incidence not known
    throat irritation / Early / Incidence not known
    dysgeusia / Early / Incidence not known
    ocular irritation / Rapid / Incidence not known
    tinnitus / Delayed / Incidence not known
    xerophthalmia / Early / Incidence not known
    diplopia / Early / Incidence not known
    increased urinary frequency / Early / Incidence not known
    testicular pain / Early / Incidence not known
    fever / Early / Incidence not known
    fatigue / Early / Incidence not known
    malaise / Early / Incidence not known
    hypothermia / Delayed / Incidence not known
    gynecomastia / Delayed / Incidence not known

    DRUG INTERACTIONS

    Abciximab: (Moderate) Unless contraindicated, aspirin is used in combination with abciximab. However, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy.
    Acalabrutinib: (Major) Avoid the concomitant use of acalabrutinib and omeprazole; decreased acalabrutinib exposure occurred in a drug interaction study. Consider using an antacid or H2-blocker if acid suppression therapy is needed. Separate the administration of acalabrutinib and antacids by at least 2 hours; give acalabrutinib 2 hours before a H2-blocker. Acalabrutinib solubility decreases with increasing pH values. The AUC of acalabrutinib was decreased by 43% when acalabrutinib was coadministered with omeprazole 40 mg/day for 5 days.
    Acetaminophen: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Aspirin, ASA; Caffeine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Butalbital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19. (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Butalbital; Caffeine: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19. (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Butalbital; Caffeine; Codeine: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19. (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Caffeine; Dihydrocodeine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Caffeine; Magnesium Salicylate; Phenyltoloxamine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Caffeine; Phenyltoloxamine; Salicylamide: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Chlorpheniramine; Phenylephrine; Phenyltoloxamine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Codeine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Dextromethorphan: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Dextromethorphan; Doxylamine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Dichloralphenazone; Isometheptene: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Diphenhydramine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Guaifenesin; Phenylephrine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Hydrocodone: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Oxycodone: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Pentazocine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Propoxyphene: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Pseudoephedrine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Tramadol: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetazolamide: (Major) Avoid the coadministration of high-dose salicylates and carbonic anhydrase inhibitors whenever possible. There were reports of anorexia, tachypnea, lethargy, metabolic acidosis, coma, and death with high-dose aspirin and acetazolamide. Two mechanisms could cause increased acetazolamide concentrations, resulting in CNS depression and metabolic acidosis: first, competition with aspirin for renal tubular secretion and, second, displacement by salicylates from plasma protein binding sites. Additionally, carbonic anhydrase inhibitors alkalinize urine and increase the excretion of normal doses of salicylates; decreased plasma salicylate concentrations may or may not be clinically significant.
    Acetohexamide: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria.
    Acidifying Agents: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Ado-Trastuzumab emtansine: (Major) Use caution if coadministration of platelet inhibitors such as aspirin, ASA with ado-trastuzumab emtansine is necessary due to reports of severe and sometimes fatal hemorrhage, including intracranial bleeding with ado-trastuzumab emtansine therapy. Per the manufacturer of ado-trastuzumab emtansine, if anti-platelet therapy cannot be avoided, additional monitoring of platelets and bleeding risk may be necessary. In a randomized, multicenter, open-label clinical trial of patients with HER2-positive metastatic breast cancer, hemorrhage occurred in 32.2% (>= grade 3, 1.8%) of patients treated with ado-trastuzumab emtansine (n = 490) compared with 16.4% (>= grade 3, 0.8%) of those who received lapatinib plus capecitabine (n = 488); some patients who experienced bleeding were also receiving anticoagulation therapy, antiplatelet therapy, or had thrombocytopenia, while others had no known additional risk factors.
    Afatinib: (Major) If the concomitant use of omeprazole and afatinib is necessary, consider reducing the afatinib dose by 10 mg per day if the original dose is not tolerated; resume the previous dose of afatinib as tolerated after discontinuation of omeprazole. Afatinib is a P-glycoprotein (P-gp) substrate and inhibitor in vitro, and omeprazole is a P-gp inhibitor; coadministration may increase plasma concentrations of afatinib. Administration of another P-gp inhibitor, ritonavir (200 mg twice daily for 3 days), 1 hour before afatinib (single dose) increased the afatinib AUC and Cmax by 48% and 39%, respectively; there was no change in the afatinib AUC when ritonavir was administered at the same time as afatinib or 6 hours later. In healthy subjects, the relative bioavailability for AUC and Cmax of afatinib was 119% and 104%, respectively, when coadministered with ritonavir, and 111% and 105% when ritonavir was administered 6 hours after afatinib. The manufacturer of afatinib recommends permanent discontinuation of therapy for severe or intolerant adverse drug reactions at a dose of 20 mg per day, but does not address a minimum dose otherwise.
    Alendronate: (Moderate) Proton pump inhibitors (PPIs) are widely used and are frequently coadministered in users of oral bisphosphonates. A national register-based, open cohort study of 38,088 elderly patients suggests that those who use proton pump inhibitors in conjunction with alendronate have a dose-dependent loss of protection against hip fracture. While causality was not investigated, the dose-response relationship noted during the study suggested that PPIs may reduce oral alendronate efficacy, perhaps through an effect on absorption or other mechanism, and therefore PPIs may not be optimal agents to control gastrointestinal complaints. It is not yet clear if all bisphosphonates would exhibit a loss of efficacy when PPIs are coadministered, but the results suggest that the interaction may occur across the class.
    Alendronate; Cholecalciferol: (Moderate) Proton pump inhibitors (PPIs) are widely used and are frequently coadministered in users of oral bisphosphonates. A national register-based, open cohort study of 38,088 elderly patients suggests that those who use proton pump inhibitors in conjunction with alendronate have a dose-dependent loss of protection against hip fracture. While causality was not investigated, the dose-response relationship noted during the study suggested that PPIs may reduce oral alendronate efficacy, perhaps through an effect on absorption or other mechanism, and therefore PPIs may not be optimal agents to control gastrointestinal complaints. It is not yet clear if all bisphosphonates would exhibit a loss of efficacy when PPIs are coadministered, but the results suggest that the interaction may occur across the class.
    Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Aliskiren; Hydrochlorothiazide, HCTZ: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Alkalinizing Agents: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
    Alogliptin: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Alogliptin; Metformin: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Alogliptin; Pioglitazone: (Moderate) Salicylates can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates can cause hyperglycemia and glycosuria. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Alpha-glucosidase Inhibitors: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Alprazolam: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as alprazolam. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Amiloride: (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. This combination may cause hyperkalemia.
    Amiloride; Hydrochlorothiazide, HCTZ: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. This combination may cause hyperkalemia. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Aminoglycosides: (Minor) Due to the inhibition of renal prostaglandins by salicylates, concurrent use of salicylates and other nephrotoxic agents like the aminoglycosides may lead to additive nephrotoxicity.
    Amitriptyline; Chlordiazepoxide: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as chlordiazepoxide. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Amlodipine; Atorvastatin: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction.
    Amlodipine; Benazepril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Amlodipine; Hydrochlorothiazide, HCTZ; Olmesartan: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Amlodipine; Hydrochlorothiazide, HCTZ; Valsartan: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Amobarbital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Amoxicillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Amoxicillin; Clarithromycin; Lansoprazole: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Amoxicillin; Clarithromycin; Omeprazole: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Amoxicillin; Clavulanic Acid: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Amphetamine: (Moderate) Proton pump inhibitors (PPIs) decrease the time to maximum concentration (Tmax) of amphetamine compared to when amphetamine is administered alone. If used together, monitor patients for clinical efficacy and adjust stimulant therapy based on clinical response. Some dosage forms of amphetamines should not be given with PPIs. Do not use Adzenys ER (amphetamine) extended-release oral suspension with gastric pH modulators, such as PPIs; concomitant use may result in dose-dumping by potentially changing the release profile of the extended-release suspension and increasing the exposure to amphetamine.
    Amphetamine; Dextroamphetamine Salts: (Moderate) Proton pump inhibitors (PPIs) decrease the time to maximum concentration (Tmax) of amphetamine compared to when amphetamine is administered alone. If used together, monitor patients for clinical efficacy and adjust stimulant therapy based on clinical response. Some dosage forms of amphetamines should not be given with PPIs. Do not use Adzenys ER (amphetamine) extended-release oral suspension with gastric pH modulators, such as PPIs; concomitant use may result in dose-dumping by potentially changing the release profile of the extended-release suspension and increasing the exposure to amphetamine.
    Amphetamine; Dextroamphetamine: (Moderate) Proton pump inhibitors (PPIs) decrease the time to maximum concentration (Tmax) of amphetamine compared to when amphetamine is administered alone. If used together, monitor patients for clinical efficacy and adjust stimulant therapy based on clinical response. Some dosage forms of amphetamines should not be given with PPIs. Do not use Adzenys ER (amphetamine) extended-release oral suspension with gastric pH modulators, such as PPIs; concomitant use may result in dose-dumping by potentially changing the release profile of the extended-release suspension and increasing the exposure to amphetamine.
    Amphotericin B cholesteryl sulfate complex (ABCD): (Minor) Concurrent use of amphotericin B and other potentially nephrotoxic medications, like the salicylates, may enhance the potential for drug-induced renal toxicity.
    Amphotericin B lipid complex (ABLC): (Minor) Concurrent use of amphotericin B and other potentially nephrotoxic medications, like the salicylates, may enhance the potential for drug-induced renal toxicity.
    Amphotericin B liposomal (LAmB): (Minor) Concurrent use of amphotericin B and other potentially nephrotoxic medications, like the salicylates, may enhance the potential for drug-induced renal toxicity.
    Amphotericin B: (Minor) Concurrent use of amphotericin B and other potentially nephrotoxic medications, like the salicylates, may enhance the potential for drug-induced renal toxicity.
    Ampicillin: (Major) Proton pump inhibitors (PPIs) have long-lasting effects on the secretion of gastric acid. For enteral ampicillin, whose bioavailability is influenced by gastric pH, the concomitant administration of PPIs can exert a significant effect on ampicillin absorption. (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Ampicillin; Sulbactam: (Major) Proton pump inhibitors (PPIs) have long-lasting effects on the secretion of gastric acid. For enteral ampicillin, whose bioavailability is influenced by gastric pH, the concomitant administration of PPIs can exert a significant effect on ampicillin absorption. (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Anagrelide: (Moderate) Use caution with the coadministration of aspirin and anagrelide. The coadministration of single or repeated doses of anagrelide and aspirin resulted in greater ex vivo anti-platelet aggregation effects than administration of aspirin alone. In an observational study, the concomitant use of anagrelide and aspirin increased the rate of major hemorrhagic events compared to patients receiving other cytoreductive therapy. Assess the risks and benefits of concomitant aspirin and anagrelide use, particularly in patients at high risk for hemorrhage. Monitor for bleeding during concomitant therapy.
    Angiotensin-converting enzyme inhibitors: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Anticholinergics: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Antithrombin III: (Moderate) Large doses of salicylates (more than 3 to 4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding. Patients taking large doses of salicylates and antithrombin III should be monitored closely for bleeding.
    Antithymocyte Globulin: (Moderate) An increased risk of bleeding may occur when salicylates are used with agents that cause clinically significant thrombocytopenia due to decreases in platelet aggregation, such as anti-thymocyte immune globulin.
    Apixaban: (Major) Large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding. Patients taking large doses of salicylates and apixaban should be monitored closely for bleeding.
    Aprepitant, Fosaprepitant: (Minor) Use caution if omeprazole and aprepitant are used concurrently and monitor for an increase in omeprazole-related adverse effects for several days after administration of a multi-day aprepitant regimen. Omeprazole is a CYP3A4 substrate. Aprepitant, when administered as a 3-day oral regimen (125 mg/80 mg/80 mg), is a moderate CYP3A4 inhibitor and inducer and may increase plasma concentrations of omeprazole. For example, a 5-day oral aprepitant regimen increased the AUC of another CYP3A4 substrate, midazolam (single dose), by 2.3-fold on day 1 and by 3.3-fold on day 5. After a 3-day oral aprepitant regimen, the AUC of midazolam (given on days 1, 4, 8, and 15) increased by 25% on day 4, and then decreased by 19% and 4% on days 8 and 15, respectively. As a single 125 mg or 40 mg oral dose, the inhibitory effect of aprepitant on CYP3A4 is weak, with the AUC of midazolam increased by 1.5-fold and 1.2-fold, respectively. After administration, fosaprepitant is rapidly converted to aprepitant and shares many of the same drug interactions. However, as a single 150 mg intravenous dose, fosaprepitant only weakly inhibits CYP3A4 for a duration of 2 days; there is no evidence of CYP3A4 induction. Fosaprepitant 150 mg IV as a single dose increased the AUC of midazolam (given on days 1 and 4) by approximately 1.8-fold on day 1; there was no effect on day 4. Less than a 2-fold increase in the midazolam AUC is not considered clinically important.
    Ardeparin: (Moderate) An additive risk of bleeding may be seen in patients receiving a low molecular weight heparin in combination with other agents known to increase the risk of bleeding such as salicylates. Monitor clinical and laboratory response closely during concurrent use.
    Armodafinil: (Moderate) In vitro data indicate that armodafinil is an inhibitor of CYP2C19. In theory, dosage reductions may be required for drugs that are largely eliminated via CYP2C19 metabolism such as omeprazole during coadministration with armodafinil. A 40% increase in exposure of omeprazole was observed during coadministration with armodafinil. The clinical significance of this interaction is unknown.
    Ascorbic Acid, Vitamin C: (Minor) Agents that acidify the urine should be avoided in patients receiving high-dose salicylates. Urinary pH changes can decrease salicylate excretion. However, if the urine is acidic prior to administration of an acidifying agent, the increase in salicylic acid concentrations should be minimal.
    Aspirin, ASA; Butalbital; Caffeine: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Aspirin, ASA; Butalbital; Caffeine; Codeine: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Aspirin, ASA; Carisoprodol: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as omeprazole, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
    Aspirin, ASA; Carisoprodol; Codeine: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as omeprazole, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
    Aspirin, ASA; Dipyridamole: (Moderate) Although aspirin may be used in combination with dipyridamole, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy.
    Atazanavir: (Severe) Coadministration of proton pump inhibitors (PPIs) with atazanavir in treatment-experienced patients is contraindicated. PPIs can be used with atazanavir in treatment-naive patients under specific administration restrictions. In treatment-naive patients >= 40 kg, the PPI dose should not exceed the equivalent of omeprazole 20 mg/day, and the PPI must be administered 12 hours before atazanavir and ritonavir; use the dosage regimen of atazanavir 300 mg boosted with ritonavir 100 mg given once daily with food. While data are insufficient to recommend atazanavir dosing in children < 40 kg receiving concomitant PPIs, the same recommendations regarding timing and maximum doses of concomitant PPIs should be followed. Closely monitor patients for antiretroviral therapeutic failure and resistance development during treatment with a PPI. A randomized, open-label, multiple-dose drug interaction study of atazanavir (300 mg) with ritonavir (100 mg) coadministered with omeprazole 40 mg found a reduction in atazanavir AUC and Cmin of 76% and 78%, respectively. Additionally, after multiple doses of omeprazole (40 mg/day) and atazanavir (400 mg/day, 2 hours after omeprazole) without ritonavir, the AUC of atazanavir was decreased by 94%, Cmax by 96%, and Cmin by 95%.
    Atazanavir; Cobicistat: (Severe) Coadministration of proton pump inhibitors (PPIs) with atazanavir in treatment-experienced patients is contraindicated. PPIs can be used with atazanavir in treatment-naive patients under specific administration restrictions. In treatment-naive patients >= 40 kg, the PPI dose should not exceed the equivalent of omeprazole 20 mg/day, and the PPI must be administered 12 hours before atazanavir and ritonavir; use the dosage regimen of atazanavir 300 mg boosted with ritonavir 100 mg given once daily with food. While data are insufficient to recommend atazanavir dosing in children < 40 kg receiving concomitant PPIs, the same recommendations regarding timing and maximum doses of concomitant PPIs should be followed. Closely monitor patients for antiretroviral therapeutic failure and resistance development during treatment with a PPI. A randomized, open-label, multiple-dose drug interaction study of atazanavir (300 mg) with ritonavir (100 mg) coadministered with omeprazole 40 mg found a reduction in atazanavir AUC and Cmin of 76% and 78%, respectively. Additionally, after multiple doses of omeprazole (40 mg/day) and atazanavir (400 mg/day, 2 hours after omeprazole) without ritonavir, the AUC of atazanavir was decreased by 94%, Cmax by 96%, and Cmin by 95%. (Minor) The plasma concentrations of omeprazole may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while omeprazole is a CYP3A4 and P-gp substrate.
    Atenolol; Chlorthalidone: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Atorvastatin: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction.
    Atorvastatin; Ezetimibe: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction.
    Atropine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Atropine; Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Atropine; Difenoxin: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Atropine; Diphenoxylate: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Atropine; Edrophonium: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Atropine; Hyoscyamine; Phenobarbital; Scopolamine: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19. (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Avanafil: (Minor) Avanafil is a weak inhibitor of CYP2C19 isoenzymes. A single avanafil (200 mg) dose increased the AUC and Cmax of a single omeprazole (40 mg) dose, a CYP2C19 substrate, given once daily for 8 days by 5.9% and 8.6%, respectively.
    Axitinib: (Minor) Monitor patients for increased axitinib-related adverse events or altered axitinib efficacy if coadministration with omeprazole occurs. Axitinib is primarily metabolized by CYP3A4, and to a lesser extent by CYP1A2, CYP2C19, and UGT1A1. Omeprazole is a CYP2C19 inhibitor and CYP1A2 inducer in vitro. Theoretically, exposure to axitinib may be affected. While the aqueous solubility of axitinib is pH dependent, with higher pH resulting in lower solubility, this effect was not significant when studied with rabeprazole; dosage adjustments are not recommended with proton pump inhibitors.
    Azilsartan; Chlorthalidone: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Azithromycin: (Minor) Both omeprazole and azithromycin are P-glycoprotein (PGP) inhibitors and substrates, so coadministration may lead to increased concentrations of either agent. Monitor patients for increased side effects if these drugs are given together.
    Bacitracin: (Minor) Additive nephrotoxicity may occur with concurrent use of systemic bacitracin and other nephrotoxic agents, including salicylates. Topical administration of any preparation containing bacitracin, especially when applied to large surface areas, also should not be given with other drugs that have a nephrotoxic potential.
    Barbiturates: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19. (Moderate) Due to high protein binding, salicylates could be displaced from binding sites, or could displace other highly protein-bound drugs such as barbiturates. An enhanced effect of the displaced drug may occur.
    Basiliximab: (Minor) Due to aspirin's effect on platelet aggregation and GI mucosa, aspirin should be used cautiously in patients with thrombocytopenia following treatment with antineoplastic agents due to an increased risk of bleeding.
    Belladonna Alkaloids; Ergotamine; Phenobarbital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19. (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Belladonna; Opium: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Benazepril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Benazepril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Bendroflumethiazide; Nadolol: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Benztropine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Beta-blockers: (Moderate) Concurrent use of beta-blockers with aspirin and other salicylates may result in loss of antihypertensive activity due to inhibition of renal prostaglandins and thus, salt and water retention and decreased renal blood flow.
    Betrixaban: (Major) Monitor patients closely and promptly evaluate any signs or symptoms of bleeding if betrixaban and aspirin are used concomitantly. Coadministration of betrixaban and aspirin may increase the risk of bleeding.
    Bisacodyl: (Minor) The concomitant use of bisacodyl oral tablets with drugs that raise gastric pH like proton pump inhibitors can cause the enteric coating of the bisacodyl tablets to dissolve prematurely, leading to possible gastric irritation or dyspepsia. When taking bisacodyl tablets, it is advisable to avoid PPIs within 1 hour before or after the bisacodyl dosage.
    Bismuth Subcitrate Potassium; Metronidazole; Tetracycline: (Minor) Coadministration of bismuth subcitrate potassium and omeprazole resulted in a significant increase in the systemic absorption of bismuth. However, when administered in the FDA-approved dosage regimen, bismuth subcitrate potassium; metronidazole; tetracycline capsules (Pylera) is administered with omeprazole for 10 days. The manufacturer does not feel that short-term exposure to bismuth concentrations > 50 mcg/L will increase the risk of neurotoxicity; health care practitioners should be aware of this potential adverse effect.
    Bismuth Subsalicylate: (Major) Concomitant use of aspirin with repeated or maximum doses of bismuth subsalicylate-containing preparations may contribute to elevated serum salicylate levels and should be avoided. Consider replacing aspirin therapy with an alternative non-steroidal anti-inflammatory agent that is not salicylate based where appropriate. (Minor) Coadministration of bismuth subcitrate potassium and omeprazole resulted in a significant increase in the systemic absorption of bismuth. However, when administered in the FDA-approved dosage regimen, bismuth subcitrate potassium; metronidazole; tetracycline capsules (Pylera) is administered with omeprazole for 10 days. The manufacturer does not feel that short-term exposure to bismuth concentrations > 50 mcg/L will increase the risk of neurotoxicity; health care practitioners should be aware of this potential adverse effect.
    Bismuth Subsalicylate; Metronidazole; Tetracycline: (Major) Concomitant use of aspirin with repeated or maximum doses of bismuth subsalicylate-containing preparations may contribute to elevated serum salicylate levels and should be avoided. Consider replacing aspirin therapy with an alternative non-steroidal anti-inflammatory agent that is not salicylate based where appropriate. (Minor) Coadministration of bismuth subcitrate potassium and omeprazole resulted in a significant increase in the systemic absorption of bismuth. However, when administered in the FDA-approved dosage regimen, bismuth subcitrate potassium; metronidazole; tetracycline capsules (Pylera) is administered with omeprazole for 10 days. The manufacturer does not feel that short-term exposure to bismuth concentrations > 50 mcg/L will increase the risk of neurotoxicity; health care practitioners should be aware of this potential adverse effect.
    Bisoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Bisphosphonates: (Moderate) Aspirin, ASA use is associated with esophageal and/or gastric irritation, and GI ulceration. Bisphosphonates may cause GI adverse events and occasionally, renal dysfunction. In clinical trials, aspirin use along with bisphosphonates increased the risk of GI events in some patients; however, some clinical trials of bisphosphonates have not reported increased rates of GI adverse events with aspirin co-use. Exercise caution when administering aspirin with a bisphosphonate. Though patients receiving intravenously administered bisphosphonates have a decreased incidence of GI adverse effects as compared to those taking orally administered bisphosphonates, nephrotoxicity is possible, and GI events are rarely reported. Monitor for the presence of GI complaints, including potential GI ulceration and bleeding, and monitor renal function during combined use.
    Boceprevir: (Moderate) Close clinical monitoring is advised when administering omeprazole with boceprevir due to an increased potential for omeprazole-related adverse events. If omeprazole dose adjustments are made, re-adjust the dose upon completion of boceprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of omeprazole. Omeprazole is a substrate of the drug efflux transporter P-glycoprotein (PGP) and of the hepatic isoenzyme CYP3A4; boceprevir is an inhibitor of both the efflux protein and the isoenzyme. Coadministration may result in elevated omeprazole plasma concentrations.
    Bortezomib: (Minor) Bortezomib may inhibit CYP2C19 activity at therapeutic concentrations and increase exposure to drugs that are substrates for this enzyme including proton pump inhibitors.
    Bosentan: (Moderate) Monitor for decreased efficacy of omeprazole if coadministration with bosentan is necessary. Omeprazole is metabolized by CYP2C19 and CYP3A4. Bosentan is a moderate CYP3A4 inducer. The manufacturer of omeprazole recommends avoidance with strong inducers because decreased exposure of omeprazole can occur. Recommendations are not available for concomitant use with moderate inducers of CYP3A4.
    Bosutinib: (Major) Bosutinib displays pH-dependent aqueous solubility; therefore, concomitant use of bosutinib and proton-pump inhibitors, such as omeprazole, may result in decreased plasma exposure of bosutinib. Consider using a short-acting antacid or H2 blocker if acid suppression therapy is needed; separate the administration of bosutinib and antacids or H2-blockers by more than 2 hours.
    Bromocriptine: (Moderate) Bromocriptine is highly bound to serum proteins. Therefore, it may increase the unbound fraction of other highly protein-bound medications (e.g., salicylates), which may alter their effectiveness and risk for side effects.
    Budesonide: (Minor) Enteric-coated budesonide granules dissolve at a pH greater than 5.5. Concomitant use of budesonide oral capsules and drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum.
    Budesonide; Formoterol: (Minor) Enteric-coated budesonide granules dissolve at a pH greater than 5.5. Concomitant use of budesonide oral capsules and drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum.
    Bumetanide: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with loop diuretics (furosemide, bumetanide, torsemide, and ethacrynic acid). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
    Buspirone: (Minor) In vitro studies showed that therapeutic levels of aspirin, ASA increased the plasma concentrations of free buspirone by 23% through plasma protein binding displacement. In vivo interaction studies with these drugs have not been performed.
    Butabarbital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Cabozantinib: (Moderate) Monitor for an increase in omeprazole-related adverse events if concomitant use with cabozantinib is necessary, as plasma concentrations of omeprazole may be increased. Cabozantinib is a P-glycoprotein (P-gp) inhibitor and omeprazole is a substrate of P-gp; the clinical relevance of this finding is unknown.
    Calcium Carbonate: (Minor) By increasing urinary pH, calcium carbonate can increase the urinary excretion of salicylates.
    Calcium Carbonate; Magnesium Hydroxide: (Minor) By increasing urinary pH, calcium carbonate can increase the urinary excretion of salicylates.
    Calcium Carbonate; Risedronate: (Major) Use of proton pump inhibitors (PPIs) with delayed-release risedronate tablets (Atelvia) is not recommended. Co-administration of drugs that raise stomach pH increases risedronate bioavailability due to faster release of the drug from the enteric coated tablet. This interaction does not apply to risedronate immediate-release tablets. In healthy subjects who received esomeprazole for 6 days, the Cmax and AUC of a single dose of risedronate delayed-release tablets (Atelvia) increased by 60% and 22%, respectively. PPIsare widely used and are frequently coadministered in users of oral bisphosphonates. A national register-based, open cohort study of 38,088 elderly patients suggests that those who use PPIs in conjunction with alendronate have a dose-dependent loss of protection against hip fracture. While causality was not investigated, the dose-response relationship noted during the study suggested that PPIs may reduce oral alendronate efficacy, perhaps through an effect on absorption or other mechanism, and therefore PPIs may not be optimal agents to control gastrointestinal complaints. Study results suggest that the interaction may occur across the class; however, other interactions have not been confirmed and data suggest that fracture protection is not diminished when risedronate is used with PPIs. A post hoc analysis of patients who took risedronate 5 mg daily during placebo-controlled clinical trials determined that risedronate significantly reduced the risk of new vertebral fractures compared to placebo, regardless of concomitant PPI use. PPI users (n = 240) and PPI non-users (n = 2489) experienced fracture risk reductions of 57% (p = 0.009) and 38% (p < 0.001), respectively. (Minor) By increasing urinary pH, calcium carbonate can increase the urinary excretion of salicylates.
    Calcium; Vitamin D: (Minor) By increasing urinary pH, calcium carbonate can increase the urinary excretion of salicylates.
    Canagliflozin: (Moderate) Canagliflozin is a substrate/weak inhibitor of drug transporter P glycoprotein (P-gp). Omeprazole is a PGP inhibitor/substrate. Theoretically, concentrations of either drug may be increased. Patients should be monitored for changes in glycemic control. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Canagliflozin; Metformin: (Moderate) Canagliflozin is a substrate/weak inhibitor of drug transporter P glycoprotein (P-gp). Omeprazole is a PGP inhibitor/substrate. Theoretically, concentrations of either drug may be increased. Patients should be monitored for changes in glycemic control. (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Candesartan; Hydrochlorothiazide, HCTZ: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Capecitabine: (Moderate) Use caution if treatment with a proton pump inhibitor (PPI) is necessary in patients taking capecitabine, as progression-free survival (PFS) and overall survival (OS) may be adversely affected. The mechanism of this potential interaction is unknown and data are conflicting. In a posthoc, retrospective, subgroup analysis of a phase 3 clinical trial in patients with advanced or metastatic gastroesophageal cancer, administration of a PPI was associated with a significant decrease in PFS and OS in patients treated with capecitabine plus oxaliplatin (CapeOx) vs. patients who did not receive a PPI; a significant difference was not observed in the CapeOx plus lapatinib arm. Demographically, there were significantly more Asian patients in the PPI arm of this analysis; according to the manufacturer of capecitabine, Japanese patients have a 36% lower Cmax and 24% lower AUC for capecitabine compared with Caucasian patients. Additionally, there was not a significant increase in concentration dependent toxicities (e.g., hand-foot syndrome, rash, and diarrhea) or dose reductions in either arm. These observations are in line with a previous retrospective study in which patients with colorectal cancer receiving PPI treatment and adjuvant capecitabine also experienced poorer relapse-free survival compared with patients not receiving a PPI. Coadministration with antacids increased exposure to capecitabine and its metabolites, but this was not clinically significant or clinically relevant. Pharmacokinetic data on the impact of a PPI on capecitabine exposure are not available.
    Capreomycin: (Major) Since capreomycin is eliminated by the kidney, coadministration with other potentially nephrotoxic drugs, including salicylates, may increase serum concentrations of either drug. Theoretically, the chronic coadministration of these drugs may increase the risk of developing nephrotoxicity, even in patients who have normal renal function. Monitor patients for changes in renal function if these drugs are coadministered.
    Captopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Captopril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Carbamazepine: (Moderate) Omeprazole may increase the Cmax, AUC, and elimination half-life of carbamazepine when given as an extended-release formulation. Monitor carbamazepine serum concentrations when omeprazole is added to the drug regimen.
    Carbenicillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Carisoprodol: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as omeprazole, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
    Carvedilol: (Moderate) Altered concentrations of omeprazole and/or carvedilol may occur during coadministration. Carvedilol and omeprazole are both substrates and inhibitors of P-glycoprotein (P-gp). Use caution if concomitant use is necessary and monitor for increased side effects.
    Cefixime: (Minor) In vitro, salicylates have displaced cefixime from its protein-binding sites, resulting in a 50% increase in free cefixime levels. The clinical significance of this effect is unclear at this time.
    Cefotetan: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
    Cefpodoxime: (Moderate) Cefpodoxime proxetil requires a low gastric pH for dissolution; therefore, concurrent administration with medications that increase gastric pH, such as proton pump inhibitors (PPIs) may decrease the bioavailability of cefpodoxime. When cefpodoxime was administered with high doses of antacids and H2-blockers, peak plasma concentrations were reduced by 24% and 42% and the extent of absorption was reduced by 27% and 32%, respectively. The rate of absorption is not affected.
    Ceftibuten: (Minor) Coadministration of 150 mg of ranitidine every 12 hours for 3 days increased the ceftibuten Cmax by 23 percent and ceftibuten AUC by 16 percent. Based on this information, increased gastric pH caused by PPIs may possibly affect the kinetics of ceftibuten.
    Cefuroxime: (Major) Avoid the concomitant use of proton pump inhibitors (PPIs) and cefuroxime. Drugs that reduce gastric acidity, such as PPIs, can interfere with the oral absorption of cefuroxime axetil and may result in reduced antibiotic efficacy.
    Celecoxib: (Major) Use celecoxib and salicylates in combination with caution. Analgesic doses of salicylates with celecoxib is not recommended due to additive gastrointestinal toxicity without additional analgesic benefit. Furthermore, cardioprotective doses of aspirin in combination with celecoxib are associated with an increased risk of gastrointestinal toxicity. In patients receiving low-dose aspirin with celecoxib over a 9-month period, GI bleeding, perforation, or obstruction was higher compared to patients taking celecoxib only (2.19% for combination vs. 0.78% for celecoxib only). Celecoxib does not exhibit antiplatelet effects and is not a substitute for aspirin when used for cardiovascular prophylaxis. However, there is no consistent evidence that concurrent use of aspirin with celecoxib mitigates the increased risk of serious cardiovascular thrombotic events associated with NSAID use.
    Ceritinib: (Moderate) Use caution if coadministration of ceritinib with omeprazole is necessary, as the bioavailability of ceritinib may be reduced. Ceritinib displays pH-dependent solubility with decreased solubility at a higher pH, but data are conflicting regarding clinical significance. In healthy subjects, the AUC and Cmax of ceritinib decreased by 76% and 79%, respectively, when a single dose was administered with esomeprazole. However, in a subgroup of patients with NSCLC from a multicenter, open-label clinical trial, the AUC and Cmax of ceritinib decreased by 30% and 25%, respectively, after a single dose was administered with proton pump inhibitors; there was no clinically meaningful effect on ceritinib exposure at steady state.
    Chlordiazepoxide: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as chlordiazepoxide. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Chlordiazepoxide; Clidinium: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as chlordiazepoxide. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole. (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Chlorothiazide: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Chlorpropamide: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria.
    Chlorthalidone: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Chlorthalidone; Clonidine: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Chondroitin; Glucosamine: (Moderate) It would be prudent for patients who take aspirin to avoid methylsulfonylmethane, MSM. Monitor patients who choose to take MSM while on aspirin therapy for bleeding. Patients taking MSM and anticoagulant drugs have reported increased anticoagulant effects such as increased bruising or blood in the stool. (Minor) Agents that acidify the urine should be avoided in patients receiving high-dose salicylates. Urinary pH changes can decrease salicylate excretion. However, if the urine is acidic prior to administration of an acidifying agent, the increase in salicylic acid concentrations should be minimal.
    Cidofovir: (Severe) The concomitant administration of cidofovir and NSAIDs, such as aspirin, is contraindicated due to the potential for increased nephrotoxicity. Aspirin should be discontinued 7 days prior to beginning cidofovir.
    Cilostazol: (Major) When significant CYP2C19 inhibitors, such as omeprazole, are administered concomitantly with cilostazol, the cilostazol dosage should be reduced by 50%. Cilostazol is metabolized by the CYP2C19 hepatic isoenzyme and appears to have pharmacokinetic interactions with many medications that are potent inhibitors of CYP2C19. When given concurrently with omeprazole, cilostazol AUC is increased by 26% and the Cmax is increased by 18%; the AUC of the active metabolite 3,4-dehydro-cilostazol is increased by 69% and the Cmax is increased by 29%. (Moderate) Use caution with the coadministration of aspirin and cilostazol. Although the short-term (<= 4 days) coadministration of aspirin and cilostazol increased the inhibition of ADP-induced platelet aggregation by 22% to 37% compared to aspirin or cilostazol use alone, no clinically significant effect on PT, aPTT, or bleeding time was observed compared to aspirin alone. In clinical trials, there was no apparent increase in hemorrhagic adverse effects in patients taking cilostazol and aspirin compared to aspirin alone. The effects of long-term coadministration are unknown. Monitor for bleeding during concomitant therapy.
    Ciprofloxacin: (Minor) Concomitant use of ciprofloxacin and omeprazole may decrease the AUC and Cmax of ciprofloxacin, but the clinical significance of this interaction is unknown. Codministration of a single tablet dose of 500 mg ciprofloxacin and once-daily administration of 20 mg omeprazole pretreatment for 4 days resulted in a 16% reduction of mean Cmax and mean AUC of ciprofloxacin. A single 1000 mg oral dose of Cipro XR administered with omeprazole (40 mg once daily for 3 days) to 18 healthy volunteers resulted in a decrease in the ciprofloxacin mean AUC by 20% and Cmax by 23%. However, coadministration of a single 1000 mg oral dose of Proquin XR given 2 hours after the third dose of omeprazole (40 mg once daily for 3 days) to 27 healthy volunteers resulted in no changes in the ciprofloxacin AUC and Cmax. If ciprofloxacin is administered with omeprazole with magnesium, chelation of the ciprofloxacin would be expected; in general, it is recommended that ciprofloxacin be administered 2 hours before or 6 hours after any divalent cations like magnesium to help limit an interaction.
    Cisplatin: (Moderate) Use aspirin cautiously in patients receiving cisplatin as there is an increased risk for nephrotoxicity. Salicylates (e.g., aspirin) inhibit renal prostaglandins, adding to the cumulative nephrotoxicity caused by cisplatin.
    Citalopram: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. (Moderate) The plasma concentration of citalopram, a CYP2C19 substrate, may be increased when administered concurrently with omeprazole, a CYP2C19 inhibitor. Because citalopram causes dose-dependent QT prolongation, the maximum daily dose should not exceed 20 mg per day in patients receiving CYP2C19 inhibitors.
    Citric Acid; Potassium Citrate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
    Citric Acid; Potassium Citrate; Sodium Citrate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
    Citric Acid; Sodium Citrate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
    Clobazam: (Moderate) A dosage reduction of clobazam may be necessary during co-administration of omeprazole. Metabolism of N-desmethylclobazam, the active metabolite of clobazam, occurs primarily through CYP2C19 and omeprazole is an inhibitor of CYP2C19. Extrapolation from pharmacogenomic data indicates that concurrent use of clobazam with moderate or potent inhibitors of CYP2C19 may result in up to a 5-fold increase in exposure to N-desmethylclobazam. Adverse effects, such as sedation, lethargy, ataxia, or insomnia may be potentiated.
    Clomipramine: (Moderate) Clomipramine may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. This may increase the risk for an upper GI bleed. (Minor) Coadministration may result in increased clomipramine exposure. Omeprazole is a CYP2C19 inhibitor and clomipramine is a CYP2C19 substrate.
    Clonazepam: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as clonazepam. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Clopidogrel: (Major) Avoid concomitant use of clopidogrel and omeprazole as it significantly reduces the antiplatelet activity of clopidogrel when given concomitantly or 12 hours apart. The American College of Cardiology Foundation (ACCF), American College of Gastroenterology (ACG) and American Heart Association (AHA) state that routine use of proton pump inhibitor (PPI) therapy is not recommended for patients at lower risk of gastrointestinal bleed but should be considered in those at high risk, such as those with a history of gastrointestinal bleed. Clinicians should carefully assess the risks and benefits of PPI use in patients on clopidogrel therapy and administration should be based on clinical need. If necessary, consider using a PPI medication with less pronounced effects on antiplatelet activity, such as rabeprazole, pantoprazole, lansoprazole, or dexlansoprazole. Clopidogrel requires hepatic biotransformation via 2 cytochrome dependent oxidative steps; the CYP2C19 isoenzyme is involved in both steps. All PPIs are CYP219 substrates, and, to varying extents, are also inhibitors; thus, it is possible that any PPI may decrease the conversion of clopidogrel to its active metabolite, thereby reducing its effectiveness. (Moderate) Although aspirin may be used in combination with clopidogrel, both drugs are associated with bleeding. In clinical trials, bleeding rates with concomitant use of aspirin and clopidogrel vs. placebo vary from similar to increased bleeding with coadministration. Monitor for bleeding during concomitant therapy.
    Clorazepate: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as clorazepate. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Clozapine: (Moderate) The addition of omeprazole to clozapine therapy resulted in a roughly 40% reduction in clozapine plasma concentrations in at least 2 patients. Omeprazole is an inducer of CYP1A2, one of the isoenzymes reponsible for the metabolism of clozapine. According to the manufacturer of clozapine, patients receiving clozapine in combination with a weak to moderate CYP1A2 inducer should be monitored for loss of effectiveness. Consideration should be given to increasing the clozapine dose if necessary. If the inducer is discontinued, monitor for adverse reactions, and consider reducing the clozapine dose if necessary.
    Cobicistat: (Minor) The plasma concentrations of omeprazole may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while omeprazole is a CYP3A4 and P-gp substrate.
    Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Alafenamide: (Minor) The plasma concentrations of omeprazole may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while omeprazole is a CYP3A4 and P-gp substrate.
    Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus. (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as omeprazole. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions. (Minor) The plasma concentrations of omeprazole may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while omeprazole is a CYP3A4 and P-gp substrate.
    Cobimetinib: (Minor) If concurrent use of cobimetinib and omeprazole is necessary, use caution and monitor for a possible increase in cobimetinib-related adverse effects. Cobimetinib is a P-glycoprotein (P-gp) substrate, and omeprazole is a P-gp inhibitor; coadministration may result in increased cobimetinib exposure. However, coadministration of cobimetinib with another P-gp inhibitor, vemurafenib (960 mg twice daily), did not result in clinically relevant pharmacokinetic drug interactions.
    Cod Liver Oil: (Moderate) Because fish oil, omega-3 fatty acids inhibit platelet aggregation, caution is advised when fish oils are used concurrently with aspirin. Theoretically, the risk of bleeding may be increased. (Moderate) Cod liver oil contains vitamin A and may increase the risk of bleeding if coadministered with platelet inhibitors.
    Colistimethate, Colistin, Polymyxin E: (Major) Theoretically, the chronic coadministration of these drugs may increase the risk of developing nephrotoxicity, even in patients who have normal renal function. Monitor patients for changes in renal function if these drugs are coadministered. Since colistimethate sodium is eliminated by the kidney, coadministration with other potentially nephrotoxic drugs, including salicylates, may increase serum concentrations of either drug.
    Collagenase: (Moderate) Cautious use of injectable collagenase by patients taking more than150 mg/day of aspirin is advised. The efficacy and safety of administering injectable collagenase to a patient taking more than150 mg/day of aspirin within 7 days before the injection are unknown. Receipt of injectable collagenase may cause an ecchymosis or bleeding at the injection site. (Minor) Agents that acidify the urine should be avoided in patients receiving high-dose salicylates. Urinary pH changes can decrease salicylate excretion. However, if the urine is acidic prior to administration of an acidifying agent, the increase in salicylic acid concentrations should be minimal.
    Conivaptan: (Moderate) Avoid coadministration of conivaptan, a CYP3A4/P-glycoprotein (P-gp) inhibitor and omeprazole, a CYP3A4/P-gp substrate. Concurrent use may result in elevated omeprazole serum concentrations. According to the manufacturer of conivaptan, concomitant use of conivaptan, a strong CYP3A4 inhibitor, and CYP3A substrates, such as omeprazole, should be avoided. Coadministration of conivaptan with other CYP3A substrates (midazolam, simvastatin, amlodipine) has resulted in increased mean AUC values (2 to 3 times). Theoretically, similar pharmacokinetic effects could be seen with omeprazole. Treatment with omeprazole may be initiated no sooner than 1 week after completion of conivaptan therapy.
    Corticosteroids: (Moderate) Salicylates or NSAIDs should be used cautiously in patients receiving corticosteroids. While there is controversy regarding the ulcerogenic potential of corticosteroids alone, concomitant administration of corticosteroids with aspirin may increase the GI toxicity of aspirin and other non-acetylated salicylates. Withdrawal of corticosteroids can result in increased plasma concentrations of salicylate and possible toxicity. Concomitant use of corticosteroids may increase the risk of adverse GI events due to NSAIDs. Although some patients may need to be given corticosteroids and NSAIDs concomitantly, which can be done successfully for short periods of time without sequelae, prolonged coadministration should be avoided.
    Cranberry, Vaccinium macrocarpon Ait.: (Minor) Agents that acidify the urine should be avoided in patients receiving high-dose salicylates. Urinary pH changes can decrease salicylate excretion. However, if the urine is acidic prior to administration of an acidifying agent, the increase in salicylic acid concentrations should be minimal.
    Cyanocobalamin, Vitamin B12: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels. (Moderate) Proton pump inhibitors may cause a decrease in the oral absorption of cyanocobalamin, vitamin B12. Patients receiving long-term therapy with proton pump inhibitors should be monitored for signs of B12 deficiency.
    Cyclosporine: (Minor) Due to the inhibition of renal prostaglandins by salicylates, concurrent use of salicylates and other nephrotoxic agents like cyclosporine may lead to additive nephrotoxicity.
    Cysteamine: (Major) Monitor white blood cell (WBC) cystine concentration closely when administering delayed-release cysteamine (Procysbi) with proton pump inhibitors (PPIs). Drugs that increase the gastric pH may cause the premature release of cysteamine from delayed-release capsules, leading to an increase in WBC cystine concentration. Concomitant administration of omeprazole 20 mg did not alter the pharmacokinetics of delayed-release cysteamine when administered with orange juice; however, the effect of omeprazole on the pharmacokinetics of delayed-release cysteamine when administered with water have not been studied.
    Dabigatran: (Moderate) Increased serum concentrations of dabigatran are possible when dabigatran, a P-glycoprotein (P-gp) substrate, is coadministered with omeprazole, a P-gp inhibitor. Patients should be monitored for increased adverse effects of dabigatran while taking products containing omeprazole including omeprazole; sodium bicarbonate. When dabigatran is administered for treatment or reduction in risk of recurrence of deep venous thrombosis (DVT) or pulmonary embolism (PE) or prophylaxis of DVT or PE following hip replacement surgery, avoid coadministration with P-gp inhibitors like omeprazole in patients with CrCl less than 50 mL/minute. When dabigatran is used in patients with non-valvular atrial fibrillation and severe renal impairment (CrCl less than 30 mL/minute), avoid coadministration with omeprazole, as serum concentrations of dabigatran are expected to be higher than when administered to patients with normal renal function. P-gp inhibition and renal impairment are the major independent factors that result in increased exposure to dabigatran.
    Dabrafenib: (Major) The concomitant use of dabrafenib and omeprazole may lead to decreased omeprazole concentrations and loss of efficacy. Use of an alternative agent is recommended. If concomitant use of these agents is unavoidable, monitor patients for loss of omeprazole efficacy. In vitro, dabrafenib is an inducer of CYP2C isoenzymes via activation of the pregnane X receptor and constitutive androstane receptor nuclear receptors. Omeprazole is a sensitive CYP2C19 substrate.
    Daclatasvir: (Minor) Systemic exposure of omeprazole, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with daclatasvir, a P-gp inhibitor. Taking these drugs together could increase or prolong the therapeutic effects of omeprazole; monitor patients for potential adverse effects.
    Dalteparin: (Moderate) An additive risk of bleeding may be seen in patients receiving a low molecular weight heparin in combination with other agents known to increase the risk of bleeding such as salicylates. Monitor clinical and laboratory response closely during concurrent use.
    Danazol: (Moderate) Danazol can decrease hepatic synthesis of procoagulant factors, increasing the possibility of bleeding when used concurrently with platelet inhibitors.
    Dapagliflozin: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Dapagliflozin; Metformin: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Dapagliflozin; Saxagliptin: (Moderate) Salicylates can indirectly increase insulin secretion, decreasing blood glucose concentrations. In large doses, salicylates may cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving saxagliptin. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Darifenacin: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Darunavir: (Moderate) Coadministration of omeprazole and darunavir boosted with ritonavir may result in decreased omeprazole concentrations. Monitor patients receiving these drugs concurrently for reduced omeprazole efficacy and, if needed, consider increasing the dose of omeprazole up to a maximum of 40 mg per day.
    Darunavir; Cobicistat: (Moderate) Coadministration of omeprazole and darunavir boosted with ritonavir may result in decreased omeprazole concentrations. Monitor patients receiving these drugs concurrently for reduced omeprazole efficacy and, if needed, consider increasing the dose of omeprazole up to a maximum of 40 mg per day. (Minor) The plasma concentrations of omeprazole may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while omeprazole is a CYP3A4 and P-gp substrate.
    Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Dosage adjustments of omeprazole may be required during concomitant administration with dasabuvir; ombitasvir; paritaprevir; ritonavir. Use of these drugs together results in decreased omeprazole serum concentrations. Monitor for decreasing efficacy and consider increasing the omeprazole dose if needed; however, adult doses should be limited to no more than 40 mg/day. The dose should be re-adjusted after completion of the 4-drug hepatitis C treatment regimen. (Moderate) Use caution when administering ritonavir and omeprazole concurrently. Ritonavir is an inhibitor of CYP3A and P-glycoprotein (P-gp), while omeprazole is a CYP3A and P-gp substrate. Coadministration may increase omeprazole exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined.
    Dasatinib: (Major) Although not specifically studied, long-term suppression of gastric acid secretion by proton pump inhibitors (PPIs) is also likely to decrease the exposure to dasatinib. The concomitant use these agents is not recommended. For example, in a study of 24 healthy subjects, administration of a single 50 mg dose of dasatinib 10 hours after famotidine reduced the AUC and Cmax of dasatinib by 61% and 63%, respectively. Because separating the administration of dasatinib and antacids by at least 2 hours minimizes the interaction, the use of antacids should be considered in place of PPIs in patients receiving dasatinib therapy.
    Deferasirox: (Moderate) Because gastric ulceration and GI bleeding have been reported in patients taking deferasirox, use caution when coadministering with other drugs known to increase the risk of peptic ulcers or gastric hemorrhage including salicylates.
    Defibrotide: (Severe) Coadministration of defibrotide with antithrombotic agents like aspirin is contraindicated. The pharmacodynamic activity and risk of hemorrhage with antithrombotic agents are increased if coadministered with defibrotide. If therapy with defibrotide is necessary, discontinue antithrombotic agents prior to initiation of defibrotide therapy. Consider delaying the onset of defibrotide treatment until the effects of the antithrombotic agent have abated.
    Delavirdine: (Major) Because proton pump inhibitors (PPIs) increase gastric pH, decreased delavirdine absorption may occur. However, since these agents affect gastric pH for an extended period, separation of doses may not eliminate the interaction. Chronic use of PPIs with delavirdine is not recommended.
    Dexamethasone: (Moderate) Monitor for decreased efficacy of omeprazole if coadministration with dexamethasone is necessary. Omeprazole is metabolized by CYP2C19 and CYP3A4. Dexamethasone is a moderate CYP3A4 inducer. The manufacturer of omeprazole recommends avoidance with strong inducers because decreased exposure of omeprazole can occur. Recommendations are not available for concomitant use with moderate inducers of CYP3A4.
    Dexmethylphenidate: (Minor) The effects of gastrointestinal pH alterations on the absorption of extended-release dexmethylphenidate (Focalin XR) have not been studied. Per the manufacturer of extended-release dexmethylphenidate, the modified release characteristics are pH-dependent. It is possible that the administration of proton pump inhibitors (PPIs) or other acid suppressants could alter the release of extended-release dexmethylphenidate, resulting in reduced or increased absorption. Patients receiving a PPI should be monitored for adverse effects and reduced therapeutic efficacy of extended-release dexmethylphenidate.
    Dextroamphetamine: (Moderate) Proton pump inhibitors (PPIs) decrease the time to maximum concentration (Tmax) of amphetamine compared to when amphetamine is administered alone. If used together, monitor patients for clinical efficacy and adjust stimulant therapy based on clinical response. Some dosage forms of amphetamines should not be given with PPIs. Do not use Adzenys ER (amphetamine) extended-release oral suspension with gastric pH modulators, such as PPIs; concomitant use may result in dose-dumping by potentially changing the release profile of the extended-release suspension and increasing the exposure to amphetamine.
    Diazepam: (Moderate) Omeprazole inhibits the CYP2C19 metabolic pathway for diazepam. Omeprazole can increase the plasma concentrations and the elimination half-life of diazepam. It is recommended that patients receiving omeprazole and diazepam concomitantly should be monitored for enhanced diazepam response. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Dichlorphenamide: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Diclofenac: (Major) Increased adverse gastrointestinal effects, including gastric ulceration or blood loss, are possible if diclofenac is used with salicylates. The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. (Moderate) If possible, avoid concurrent use of diclofenac with inhibitors of CYP2C9, such as omeprazole; if coadministration is required, do not exceed a total daily diclofenac dose of 100 mg. When used with a CYP2C9 inhibitor the systemic exposure to diclofenac (a CYP2C9 substrate) may increase, potentially resulting in adverse events.
    Diclofenac; Misoprostol: (Major) Increased adverse gastrointestinal effects, including gastric ulceration or blood loss, are possible if diclofenac is used with salicylates. The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. (Moderate) If possible, avoid concurrent use of diclofenac with inhibitors of CYP2C9, such as omeprazole; if coadministration is required, do not exceed a total daily diclofenac dose of 100 mg. When used with a CYP2C9 inhibitor the systemic exposure to diclofenac (a CYP2C9 substrate) may increase, potentially resulting in adverse events.
    Dicloxacillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Dicyclomine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Diflunisal: (Major) The concurrent use of diflunisal and salicylates is not recommended due to the increased risk of gastrointestinal toxicity with little or no increase in anti-inflammatory efficacy.
    Digoxin: (Moderate) Omeprazole or other proton pump inhibitors (PPIs) can affect digoxin absorption due to their long-lasting effect on gastric acid secretion. Additionally, PPIs may slightly increase digoxin bioavailability. Omeprazole increases the AUC of digoxin by about 10%. Patients with digoxin serum levels at the upper end of the therapeutic range may need to be monitored for potential increases in serum digoxin levels when a PPI is coadministered with digoxin. Finally, PPIs have been associated with hypomagnesemia. Because, low serum magnesium may lead to irregular heartbeat and increase the likelihood of serious cardiac arrhythmias, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and digoxin concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement.
    Diphenhydramine; Ibuprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity. The FDA issued an advisory that 400 mg of ibuprofen can interfere with the antiplatelet effects of low dose aspirin (81 mg per day). Routine use of ibuprofen is likely to have the most significant effect. The FDA recommends administering ibuprofen 8 hours before or 30 minutes after aspirin if concurrent therapy is needed. Interactions have been noted between ibuprofen and aspirin, ASA. Concurrent use of chronic ibuprofen therapy (800 mg three times daily) seems to antagonize the inhibition of platelet cyclooxygenase (COX)-1 activity and impairment of platelet aggregation by low-dose aspirin (81 mg once daily) per an ex vivo analysis. In this study, diclofenac or rofecoxib therapy, agents with less activity at COX-1 than ibuprofen, did not affect inhibition of platelet aggregation by aspirin. An in vitro study has shown that the antagonism of aspirin platelet inhibition probably involves competition at platelet-derived COX-1 and is related to the NSAIDs' ability to inhibit COX-1 mediated thromboxane B2 production in platelets. Clinically, the interaction may be more dramatic with regular as compared with intermittent ibuprofen usage. Quantification of the risk was determined by the analysis of retrospective data, which may be inaccurate and incomplete. However, a trend towards a greater risk of a second myocardial infarction in the year after the initial event among adults taking daily aspirin was associated with a greater length of ibuprofen exposure.
    Diphenhydramine; Naproxen: (Major) Aspirin, ASA displaces naproxen from binding to albumin and increases naproxen excretion. Due to an increased free fraction of naproxen, increased adverse gastrointestinal effects are possible if naproxen is used with aspirin. In addition, further benefit with use of the two drugs as compared with aspirin monotherapy is not apparent, and antagonism of the irreversible platelet effect of aspirin occurs with concurrent use. The interaction appears to be due to competition at the enzyme active site. Patients who take low-dose aspirin for cardiovascular health may have the beneficial effects of aspirin on platelet function counteracted by naproxen. Concomitant aspirin and naproxen use is not recommended. The use of Naproxen with other salicylates can also lead to additive GI toxicity.
    Dipyridamole: (Moderate) Although aspirin may be used in combination with dipyridamole, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy.
    Disulfiram: (Minor) In one patient, the combined use of disulfiram and omeprazole caused disorientation, confusion, and nightmares. These reactions occurred on two separate challenges when omeprazole was added to disulfiram therapy. Caution is advised when using disulfiram and omeprazole together.
    Doxepin: (Moderate) Doxepin is primarily metabolized by CYP2C19 and CYP2D6, and to a lesser extent, by CYP1A2 and CYP2C9. Omeprazole inhibits the CYP2C19 isoenzyme in vitro and in vivo and the CYP2C9 isoenzyme in vitro. In vitro, omeprazole induces the CYP1A2 isoenzyme. The clinical significance of this potential interaction is not known; monitor patients receiving doxepin and omeprazole concurrently for both doxepin efficacy and potential adverse effects.
    Doxercalciferol: (Moderate) Cytochrome P450 enzyme inhibitors, such as omeprazole, may inhibit the 25-hydroxylation of doxercalciferol, thereby decreasing the formation of the active metabolite and thus, decreasing efficacy.
    Doxorubicin: (Moderate) Omeprazole is a P-glycoprotein (P-gp) inhibitor and doxorubicin is a major substrate of P-gp. Clinically significant interactions have been reported when doxorubicin was coadministered with inhibitors of P-gp, resulting in increased concentration and clinical effect of doxorubicin. Avoid coadministration of omeprazole and doxorubicin if possible. If not possible, closely monitor for increased side effects of doxorubicin including myelosuppression and cardiotoxicity.
    Dronabinol, THC: (Major) Use caution if coadministration of dronabinol with omeprazole is necessary, and monitor for an increase in dronabinol-related adverse reactions (e.g., feeling high, dizziness, confusion, somnolence). Dronabinol is a CYP2C9 and 3A4 substrate; omeprazole is a moderate inhibitor of CYP2C9 in vitro. Concomitant use may result in elevated plasma concentrations of dronabinol.
    Dronedarone: (Moderate) Dronedarone is metabolized by and is an inhibitor of CYP3A. Omeprazole is a substrate for CYP3A4. The concomitant administration of dronedarone and CYP3A substrates may result in increased exposure of the substrate and should, therefore, be undertaken with caution.
    Drotrecogin Alfa: (Major) Treatment with drotrecogin alfa should be carefully considered in patients who are receiving or have received salicylates within 7 days. These patients are at increased risk of bleeding during drotrecogin alfa therapy. Caution should be used when drotrecogin alfa is used with any other drugs that affect hemostasis.
    Edoxaban: (Major) Large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding. Patients taking large doses of salicylates and edoxaban should be monitored closely for bleeding. (Moderate) Coadministration of edoxaban and omeprazole may result in increased concentrations of edoxaban. Edoxaban is a P-glycoprotein (P-gp) substrate and omeprazole is a P-gp inhibitor. Increased concentrations of edoxaban may occur during concomitant use of omeprazole; monitor for increased adverse effects of edoxaban. Dosage reduction may be considered for patients being treated for deep venous thrombosis (DVT) or pulmonary embolism.
    Efalizumab: (Minor) Due to aspirin's effect on platelet aggregation and GI mucosa, aspirin should be used cautiously in patients with thrombocytopenia following treatment with antineoplastic agents due to an increased risk of bleeding.
    Efavirenz: (Minor) Efavirenz inhibits CYP2C9 and CYP2C19 and may inhibit the metabolism of omeprazole since it is a substrate for CYP2C9 or CYP2C19.
    Efavirenz; Emtricitabine; Tenofovir: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus. (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as omeprazole. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions. (Minor) Efavirenz inhibits CYP2C9 and CYP2C19 and may inhibit the metabolism of omeprazole since it is a substrate for CYP2C9 or CYP2C19.
    Eliglustat: (Minor) Coadministration of omeprazole and eliglustat may result in increased plasma concentrations of omeprazole. Monitor patients closely for omeprazole-related adverse effects; if appropriate, consider reducing the omeprazole dosage and titrating to clinical effect. Omeprazole is a P-glycoprotein (P-gp) substrate; eliglustat is a P-gp inhibitor.
    Eltrombopag: (Moderate) Eltrombopag is metabolized by CYP1A2. The significance of administering inducers of CYP1A2, such as omeprazole, on the systemic exposure of eltrombopag has not been established. Monitor patients for a decrease in the efficacy of eltrombopag if these drugs are coadministered.
    Empagliflozin: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Empagliflozin; Linagliptin: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents, such as linagliptin. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Empagliflozin; Metformin: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Emtricitabine; Rilpivirine; Tenofovir alafenamide: (Severe) Concurrent use of proton pump inhibitors and rilpivirine is contraindicated; when these drugs are coadministered, there is a potential for treatment failure and/or the development of rilpivirine or NNRTI resistance. Proton pump inhibitors inhibit secretion of gastric acid by proton pumps thereby increasing the gastric pH; for optimal absorption, rilpivirine requires an acidic environment. Coadministration of a proton pump inhibitor and rilpivirine may result in decreased rilpivirine absorption/serum concentrations, which could cause impaired virologic response to rilpivirine.
    Emtricitabine; Rilpivirine; Tenofovir disoproxil fumarate: (Severe) Concurrent use of proton pump inhibitors and rilpivirine is contraindicated; when these drugs are coadministered, there is a potential for treatment failure and/or the development of rilpivirine or NNRTI resistance. Proton pump inhibitors inhibit secretion of gastric acid by proton pumps thereby increasing the gastric pH; for optimal absorption, rilpivirine requires an acidic environment. Coadministration of a proton pump inhibitor and rilpivirine may result in decreased rilpivirine absorption/serum concentrations, which could cause impaired virologic response to rilpivirine. (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus. (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as omeprazole. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
    Emtricitabine; Tenofovir disoproxil fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus. (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as omeprazole. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
    Enalapril, Enalaprilat: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Enalapril; Felodipine: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Enalapril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Enoxaparin: (Moderate) An additive risk of bleeding may be seen in patients receiving a low molecular weight heparin in combination with other agents known to increase the risk of bleeding such as salicylates. Monitor clinical and laboratory response closely during concurrent use.
    Enzalutamide: (Major) Avoid concomitant use of enzalutamide, a strong CYP3A4 inducer and a moderate CYP2C19 inducer, and omeprazole, a CYP3A4 and CYP2C19 substrate, as omeprazole plasma exposure may be reduced. In a drug interaction trial in patients with castration-resistant prostate cancer, the AUC and Cmax of omeprazole was decreased following a single oral dose of omeprazole 20 mg administered after at least 55 days of oral enzalutamide 160 mg/day.
    Epoprostenol: (Moderate) When used concurrently with platelet inhibitors, epoprostenol may increase the risk of bleeding.
    Eprosartan; Hydrochlorothiazide, HCTZ: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Eptifibatide: (Moderate) Unless contraindicated, aspirin is used in combination with eptifibatide. However, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy.
    Erlotinib: (Major) Avoid the coadministration of erlotinib with omeprazole if possible, as there are multiple issues with concomitant use. Erlotinib solubility is pH dependent, and solubility decreases as pH increase; increasing the dose may not compensate for this loss of exposure. Additionally, erlotinib is primarily metabolized by CYP3A4, and to a lesser extent by CYP1A2. Omeprazole is a CYP1A2 inducer in vitro. The manufacturer recommends increasing the dose of erlotinib by 50 mg increments at 2-week intervals to a maximum of 300 mg when used with CYP1A2 inducers; however, this may not be effective due to the solubility issue. Omeprazole decreased the AUC and Cmax of erlotinib by 46% and 61%, respectively. In addition to the pharmacokinetic interaction, In a single-dose pharmacokinetics trial in healthy volunteers, cigarette smoking (moderate CYP1A2 inducer) decreased the AUC of erlotinib by 64% (95% CI, 46% to 76%) in current smokers compared with former/never smokers. Steady-state trough concentrations of erlotinib were approximately 2-fold less in current smokers compared with former/never smokers in a separate study of patients with NSCLC. Coadministration with omeprazole may also decrease erlotinib exposure.
    Escitalopram: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. (Moderate) The plasma concentration of escitalopram, a CYP2C19 substrate, may be increased when administered concurrently with omeprazole, a CYP2C19 inhibitor. If these drugs are used together, monitor for escitalopram-associated adverse reactions.
    Eslicarbazepine: (Moderate) Eslicarbazepine may inhibit the CYP2C19-mediated and induce the CYP3A4-mediated metabolism of omeprazole; both enzymes are involved in the metabolism of proton pump inhibitors (PPIs). It is unclear that the theoretical interaction would result in a net increase or decrease in PPI action. Some manufacturers recommend avoiding the coadministration of hepatic cytochrome P-450 enzyme inducers and PPIs. If eslicarbazepine and PPI must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy, or for signs of PPI side effects.
    Esomeprazole; Naproxen: (Major) Aspirin, ASA displaces naproxen from binding to albumin and increases naproxen excretion. Due to an increased free fraction of naproxen, increased adverse gastrointestinal effects are possible if naproxen is used with aspirin. In addition, further benefit with use of the two drugs as compared with aspirin monotherapy is not apparent, and antagonism of the irreversible platelet effect of aspirin occurs with concurrent use. The interaction appears to be due to competition at the enzyme active site. Patients who take low-dose aspirin for cardiovascular health may have the beneficial effects of aspirin on platelet function counteracted by naproxen. Concomitant aspirin and naproxen use is not recommended. The use of Naproxen with other salicylates can also lead to additive GI toxicity.
    Estazolam: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as estazolam. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Ethacrynic Acid: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with loop diuretics (furosemide, bumetanide, torsemide, and ethacrynic acid). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
    Ethanol: (Major) Concomitant ingestion of ethanol with salicylates, especially aspirin, ASA, increases the risk of developing gastric irritation and GI mucosal bleeding. Ethanol and salicylates are mucosal irritants and aspirin decreases platelet aggregation. Routine ingestion of ethanol and aspirin can cause significant GI bleeding, which may or may not be overt. Even occasional concomitant use of salicylates and ethanol should be avoided. Chronic alcoholism is often associated with hypoprothrombinemia and this condition increases the risk of salicylate-induced bleeding. Patients should be warned regarding the potential for increased risk of GI bleeding if alcohol-containing beverages are taken concurrently with salicylates
    Ethotoin: (Minor) Large doses of salicylates can displace hydantoins from plasma protein-binding sites. Although increased serum concentrations of unbound phenytoin may lead to phenytoin toxicity, the liver may also more rapidly clear unbound drug.
    Etodolac: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Etoposide, VP-16: (Major) Monitor for an increase in etoposide-related adverse effects if etoposide, VP-16 is coadministered with aspirin, ASA. Etoposide is highly protein bound (97% to albumin); aspirin displaced protein-bound etoposide at concentrations achieved in vivo in a study evaluating the effect of other drugs on the binding of carbon-14 labeled etoposide to human serum proteins. (Major) Monitor for an increased incidence of etoposide-related adverse effects if used concomitantly with omeprazole. Omeprazole is an inhibitor of P-glycoprotein (P-gp) and etoposide, VP-16 is a P-gp substrate. Coadministration may increase etoposide concentrations.
    Ezetimibe; Simvastatin: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction.
    Famotidine; Ibuprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity. The FDA issued an advisory that 400 mg of ibuprofen can interfere with the antiplatelet effects of low dose aspirin (81 mg per day). Routine use of ibuprofen is likely to have the most significant effect. The FDA recommends administering ibuprofen 8 hours before or 30 minutes after aspirin if concurrent therapy is needed. Interactions have been noted between ibuprofen and aspirin, ASA. Concurrent use of chronic ibuprofen therapy (800 mg three times daily) seems to antagonize the inhibition of platelet cyclooxygenase (COX)-1 activity and impairment of platelet aggregation by low-dose aspirin (81 mg once daily) per an ex vivo analysis. In this study, diclofenac or rofecoxib therapy, agents with less activity at COX-1 than ibuprofen, did not affect inhibition of platelet aggregation by aspirin. An in vitro study has shown that the antagonism of aspirin platelet inhibition probably involves competition at platelet-derived COX-1 and is related to the NSAIDs' ability to inhibit COX-1 mediated thromboxane B2 production in platelets. Clinically, the interaction may be more dramatic with regular as compared with intermittent ibuprofen usage. Quantification of the risk was determined by the analysis of retrospective data, which may be inaccurate and incomplete. However, a trend towards a greater risk of a second myocardial infarction in the year after the initial event among adults taking daily aspirin was associated with a greater length of ibuprofen exposure.
    Fenofibric Acid: (Minor) At therapeutic concentrations, fenofibric acid is a weak inhibitor of CYP2C19. Concomitant use of fenofibric acid with CYP2C19 substrates, such as omeprazole, has not been formally studied. Fenofibric acid may theoretically increase plasma concentrations of CYP2C19 substrates and could lead to toxicity for drugs that have a narrow therapeutic range. Monitor the therapeutic effect of omeprazole during coadministration with fenofibric acid.
    Fenoprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Fesoterodine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Fish Oil, Omega-3 Fatty Acids (Dietary Supplements): (Moderate) Because fish oil, omega-3 fatty acids inhibit platelet aggregation, caution is advised when fish oils are used concurrently with aspirin. Theoretically, the risk of bleeding may be increased.
    Flavocoxid, Flavocoxid; Citrated Zinc Bisglycinate: (Major) Because flavocoxid has been associated with isolated cases of occult GI bleeding, additive pharmacodynamic effects may be seen in patients receiving salicylates. Avoid the concurrent use of flavocoxid with salicylates until further data are available.
    Flavoxate: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Flibanserin: (Major) The concomitant use of flibanserin and strong CYP2C19 inhibitors, such as proton pump inhibitors (PPIs), may increase flibanserin concentrations, resulting in severe hypotension, syncope, and/or CNS depression. Therefore, patients should be monitored for flibanserin-induced adverse reactions, and the risks of combination therapy should be discussed with the patient. In addition, the concomitant use of flibanserin and multiple weak CYP3A4 inhibitors, including pantoprazole, may increase flibanserin concentrations, which may increase the risk of flibanserin-induced adverse reactions.
    Fluoxetine: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
    Fluoxetine; Olanzapine: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
    Flurazepam: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as flurazepam. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Flurbiprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Fluvastatin: (Moderate) Concomitant administration of omeprazole with fluvastatin can decrease fluvastatin clearance by 18 to 23%, and increase AUC by 24 to 33%.
    Fluvoxamine: (Moderate) Omeprazole is a primary substrate of CYP2C19 and CYP3A4. Reduced metabolism and resulting elevated plasma concentrations of omeprazole may occur if combined with fluvoxamine. Fluvoxamine is a strong inhibitor of CYP2C19 and a moderate inhibitor of CYP3A4. Concomitant administration of omeprazole and a combined inhibitor of CYP2C19 and CYP3A4 resulted in more than doubling of the omeprazole exposure. No specific dose adjustments are recommended, unless the patient is receiving high doses of omeprazole, as for Zollinger-Ellison Syndrome; in such patients, omeprazole dose reduction might be necessary. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
    Fondaparinux: (Moderate) An additive risk of bleeding may be seen in patients receiving platelet inhibitors (e.g. aspirin, ASA) in combination with fondaparinux. Data on the concomitant use of fondaparinux with aspirin are lacking; however, large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding.
    Foscarnet: (Minor) Due to the inhibition of renal prostaglandins by salicylates, concurrent use of salicylates and other nephrotoxic agents, such as foscarnet, may lead to additive nephrotoxicity.
    Fosinopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Fosinopril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Fosphenytoin: (Moderate) Omeprazole can exhibit a dose-dependent inhibition of the hepatic cytochrome P-450 enzyme system, specifically CYP2C19. Because of this, omeprazole can interfere with the clearance of drugs metabolized via this pathway, such as phenytoin or fosphenytoin, resulting in increased phenytoin plasma concentrations. Clinical data do not exist, but an interaction is possible based on the known pathways of elimination. Patients should be monitored carefully for signs of increased drug effect if omeprazole is used with these drugs. In addition, some manufacturers recommend avoiding the coadministration of hepatic cytochrome P-450 enzyme inducers and proton pump inhibitors (PPIs). Phenytoin induces hepatic cytochrome P-450 enzymes, including those responsible for the metabolism of PPIs (e.g., CYP3A4, CYP2C19). A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If phenytoin and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy. (Minor) Large doses of salicylates can displace phenytoin from plasma protein-binding sites. Although increased serum concentrations of unbound phenytoin may lead to phenytoin toxicity, the liver may also more rapidly clear unbound drug. Fosphenytoin is converted to phenytoin in vivo, so this interaction may also occur with fosphenytoin.
    Furosemide: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with loop diuretics (furosemide, bumetanide, torsemide, and ethacrynic acid). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
    Garlic, Allium sativum: (Moderate) Garlic, Allium sativum may produce clinically-significant antiplatelet effects; until more data are available, garlic should be used cautiously in patients receiving drugs with a potential risk for bleeding such as aspirin, ASA.
    Gefitinib: (Moderate) If possible, avoid the concomitant use of gefitinib with omeprazole. If coadministration is necessary, give gefitinib 12 hours after the last dose or 12 hours before the next dose of omeprazole. Drugs that increase gastric pH may decrease plasma concentrations of gefitinib; coadministration of high doses of ranitidine with sodium bicarbonate (to maintain the gastric pH above 5) to healthy subjects decreased mean gefitinib AUC by 47%.
    Ginger, Zingiber officinale: (Moderate) There may be an increased risk of bleeding in patients on aspirin therapy who take ginger as a supplement (i.e., usual dietary intake is not expected to pose a risk). Several pungent constituents of ginger, Zingiber officinale are reported to inhibit arachidonic acid induced platelet activation in human whole blood. Ginger-associated platelet inhibition may be related to a decrease in COX-1/Thromboxane synthase enzymatic activity. The increased risk of bleeding is theoretical; clinical data of an interaction are not available.
    Ginkgo, Ginkgo biloba: (Major) Avoid Ginkgo biloba in patients on aspirin therapy, as there is an increased risk of bleeding. Ginkgo biloba inhibits platelet aggregation; several case reports describe bleeding complications, with or without concomitant drug therapy.
    Glimepiride: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria.
    Glimepiride; Pioglitazone: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. (Moderate) Salicylates can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates can cause hyperglycemia and glycosuria.
    Glimepiride; Rosiglitazone: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. (Moderate) Salicylates can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates can cause hyperglycemia and glycosuria.
    Glipizide: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria.
    Glipizide; Metformin: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control.
    Glyburide: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria.
    Glyburide; Metformin: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control.
    Glycopyrrolate: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Glycopyrrolate; Formoterol: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Green Tea: (Moderate) Green tea should be used cautiously in patients taking aspirin; there may be an increased risk of bleeding. Monitoring clinical and/or laboratory parameters is warranted. Green tea has demonstrated antiplatelet and fibrinolytic actions in animals.
    Griseofulvin: (Moderate) Concurrent administration of griseofulvin with salicylates may result in decreased salicylate serum concentrations. Caution and close monitoring for changes in the effectiveness of the salicylate are recommended.
    Guarana: (Moderate) Guarana has been shown to possess minor antiplatelet activity and, therefore, concurrent use of guarana and anticoagulants or platelet inhibitors should be avoided.
    Heparin: (Moderate) An additive risk of bleeding may be seen in patients receiving platelet inhibitors (e.g. aspirin, ASA). Despite the potential drug-drug interaction between aspirin and heparin, heparin is frequently administered in combination with low-dose aspirin therapy to patients who have had an acute myocardial infarction and in other disease states. In addition, large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding.
    Homatropine; Hydrocodone: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Hyaluronidase, Recombinant; Immune Globulin: (Moderate) Immune Globulin (IG) products have been reported to be associated with renal dysfunction, acute renal failure, osmotic nephrosis, and death. Patients predisposed to acute renal failure include patients receiving known nephrotoxic drugs like nonsteroidal anti-inflammatory drugs (NSAIDs) and salicylates. Coadminister IG products at the minimum concentration available and the minimum rate of infusion practicable. Also, closely monitor renal function. (Minor) Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients receiving these medications may require larger amounts of hyaluronidase for equivalent dispersing effect.
    Hyaluronidase: (Minor) Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients receiving these medications may require larger amounts of hyaluronidase for equivalent dispersing effect.
    Hydralazine; Hydrochlorothiazide, HCTZ: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Irbesartan: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Lisinopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Losartan: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Metoprolol: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Moexipril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Olmesartan: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Propranolol: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Quinapril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Spironolactone: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. This combination may cause hyperkalemia. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Telmisartan: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Triamterene: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. This combination may cause hyperkalemia. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrochlorothiazide, HCTZ; Valsartan: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Hydrocodone; Ibuprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity. The FDA issued an advisory that 400 mg of ibuprofen can interfere with the antiplatelet effects of low dose aspirin (81 mg per day). Routine use of ibuprofen is likely to have the most significant effect. The FDA recommends administering ibuprofen 8 hours before or 30 minutes after aspirin if concurrent therapy is needed. Interactions have been noted between ibuprofen and aspirin, ASA. Concurrent use of chronic ibuprofen therapy (800 mg three times daily) seems to antagonize the inhibition of platelet cyclooxygenase (COX)-1 activity and impairment of platelet aggregation by low-dose aspirin (81 mg once daily) per an ex vivo analysis. In this study, diclofenac or rofecoxib therapy, agents with less activity at COX-1 than ibuprofen, did not affect inhibition of platelet aggregation by aspirin. An in vitro study has shown that the antagonism of aspirin platelet inhibition probably involves competition at platelet-derived COX-1 and is related to the NSAIDs' ability to inhibit COX-1 mediated thromboxane B2 production in platelets. Clinically, the interaction may be more dramatic with regular as compared with intermittent ibuprofen usage. Quantification of the risk was determined by the analysis of retrospective data, which may be inaccurate and incomplete. However, a trend towards a greater risk of a second myocardial infarction in the year after the initial event among adults taking daily aspirin was associated with a greater length of ibuprofen exposure.
    Hyoscyamine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Ibritumomab Tiuxetan: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels. (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
    Ibrutinib: (Major) Use caution with concomitant use of ibrutinib and antiplatelet agents such as aspirin, ASA. Bleeding or bruising events occurred in 48% to 63% (grade 3 or 4, 5% to 6%) of patients treated with ibrutinib in clinical trials. The mechanism for bleeding is not well understood, and the risk of hemorrhage may be increased in patients receiving antiplatelet therapy. Also, aspirin may mask signs of infection such as fever and in patients following treatment with antineoplastic agents or immunosuppressives. Aspirin, ASA should be used with caution in patients receiving immunosuppressive therapy.
    Ibuprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity. The FDA issued an advisory that 400 mg of ibuprofen can interfere with the antiplatelet effects of low dose aspirin (81 mg per day). Routine use of ibuprofen is likely to have the most significant effect. The FDA recommends administering ibuprofen 8 hours before or 30 minutes after aspirin if concurrent therapy is needed. Interactions have been noted between ibuprofen and aspirin, ASA. Concurrent use of chronic ibuprofen therapy (800 mg three times daily) seems to antagonize the inhibition of platelet cyclooxygenase (COX)-1 activity and impairment of platelet aggregation by low-dose aspirin (81 mg once daily) per an ex vivo analysis. In this study, diclofenac or rofecoxib therapy, agents with less activity at COX-1 than ibuprofen, did not affect inhibition of platelet aggregation by aspirin. An in vitro study has shown that the antagonism of aspirin platelet inhibition probably involves competition at platelet-derived COX-1 and is related to the NSAIDs' ability to inhibit COX-1 mediated thromboxane B2 production in platelets. Clinically, the interaction may be more dramatic with regular as compared with intermittent ibuprofen usage. Quantification of the risk was determined by the analysis of retrospective data, which may be inaccurate and incomplete. However, a trend towards a greater risk of a second myocardial infarction in the year after the initial event among adults taking daily aspirin was associated with a greater length of ibuprofen exposure.
    Ibuprofen; Oxycodone: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity. The FDA issued an advisory that 400 mg of ibuprofen can interfere with the antiplatelet effects of low dose aspirin (81 mg per day). Routine use of ibuprofen is likely to have the most significant effect. The FDA recommends administering ibuprofen 8 hours before or 30 minutes after aspirin if concurrent therapy is needed. Interactions have been noted between ibuprofen and aspirin, ASA. Concurrent use of chronic ibuprofen therapy (800 mg three times daily) seems to antagonize the inhibition of platelet cyclooxygenase (COX)-1 activity and impairment of platelet aggregation by low-dose aspirin (81 mg once daily) per an ex vivo analysis. In this study, diclofenac or rofecoxib therapy, agents with less activity at COX-1 than ibuprofen, did not affect inhibition of platelet aggregation by aspirin. An in vitro study has shown that the antagonism of aspirin platelet inhibition probably involves competition at platelet-derived COX-1 and is related to the NSAIDs' ability to inhibit COX-1 mediated thromboxane B2 production in platelets. Clinically, the interaction may be more dramatic with regular as compared with intermittent ibuprofen usage. Quantification of the risk was determined by the analysis of retrospective data, which may be inaccurate and incomplete. However, a trend towards a greater risk of a second myocardial infarction in the year after the initial event among adults taking daily aspirin was associated with a greater length of ibuprofen exposure.
    Ibuprofen; Pseudoephedrine: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity. The FDA issued an advisory that 400 mg of ibuprofen can interfere with the antiplatelet effects of low dose aspirin (81 mg per day). Routine use of ibuprofen is likely to have the most significant effect. The FDA recommends administering ibuprofen 8 hours before or 30 minutes after aspirin if concurrent therapy is needed. Interactions have been noted between ibuprofen and aspirin, ASA. Concurrent use of chronic ibuprofen therapy (800 mg three times daily) seems to antagonize the inhibition of platelet cyclooxygenase (COX)-1 activity and impairment of platelet aggregation by low-dose aspirin (81 mg once daily) per an ex vivo analysis. In this study, diclofenac or rofecoxib therapy, agents with less activity at COX-1 than ibuprofen, did not affect inhibition of platelet aggregation by aspirin. An in vitro study has shown that the antagonism of aspirin platelet inhibition probably involves competition at platelet-derived COX-1 and is related to the NSAIDs' ability to inhibit COX-1 mediated thromboxane B2 production in platelets. Clinically, the interaction may be more dramatic with regular as compared with intermittent ibuprofen usage. Quantification of the risk was determined by the analysis of retrospective data, which may be inaccurate and incomplete. However, a trend towards a greater risk of a second myocardial infarction in the year after the initial event among adults taking daily aspirin was associated with a greater length of ibuprofen exposure.
    Idelalisib: (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with omeprazole, a CYP3A substrate, as omeprazole toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib.
    Iloprost: (Moderate) When used concurrently with platelet inhibitors, inhaled iloprost may increase the risk of bleeding.
    Immune Globulin IV, IVIG, IGIV: (Moderate) Immune Globulin (IG) products have been reported to be associated with renal dysfunction, acute renal failure, osmotic nephrosis, and death. Patients predisposed to acute renal failure include patients receiving known nephrotoxic drugs like nonsteroidal anti-inflammatory drugs (NSAIDs) and salicylates. Coadminister IG products at the minimum concentration available and the minimum rate of infusion practicable. Also, closely monitor renal function.
    Incretin Mimetics: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents. Monitor blood glucose closely during coadministration.
    Indacaterol; Glycopyrrolate: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Indapamide: (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics because salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance.
    Indinavir: (Major) Omeprazole has been reported to decrease the oral bioavailability of indinavir. In one study, indinavir plasma levels fell to below 95% of normal in roughly half of the patients receiving omeprazole concurrently. An increase in indinavir dosage resolved the interaction. It is unclear if other gastric acid-pump inhibitors would interact with indinavir in this manner.
    Indomethacin: (Major) The concurrent use of salicylates and indomethacin is not recommended. Combined use does not produce any greater therapeutic effect than indomethacin monotherapy. Also, a significantly greater incidence of gastrointestinal adverse effects with concurrent use has been observed. Because NSAIDs can cause GI bleeding, inhibit platelet aggregation, and prolong bleeding time, additive effects may be seen in patients receiving platelet inhibitors (e.g., aspirin), anticoagulants, or thrombolytic agents.
    Insulins: (Moderate) Use large doses of aspirin cautiously in patients receiving insulin. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia.
    Intravenous Lipid Emulsions: (Moderate) Because fish oil, omega-3 fatty acids inhibit platelet aggregation, caution is advised when fish oils are used concurrently with aspirin. Theoretically, the risk of bleeding may be increased.
    Iron: (Major) The bioavailability of oral iron salts is influenced by gastric pH, and the concomitant administration of proton pump inhibitors can decrease iron absorption. The non-heme ferric form of iron needs an acidic intragastric pH to be reduced to ferrous and to be absorbed. Iron salts and polysaccharide-iron complex provide non-heme iron. Proton pump inhibitors have long-lasting effects on the secretion of gastric acid and thus, increase the pH of the stomach. The increase in intragastric pH can interfere with the absorption of iron salts.
    Isavuconazonium: (Moderate) Concomitant use of isavuconazonium with omeprazole may result in increased serum concentrations of omeprazole. Omeprazole is a substrate of the hepatic isoenzyme CYP3A4 and drug transporter P-glycoprotein (P-gp); isavuconazole, the active moiety of isavuconazonium, is an inhibitor of CYP3A4 and P-gp. Caution and close monitoring are advised if these drugs are used together.
    Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Major) Some manufacturers recommend avoiding the coadministration of rifampin and proton pump inhibitors (PPIs). Rifamycins induce multiple hepatic cytochrome P-450 enzymes, including those responsible for the metabolism of PPIs. A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If rifampin and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy.
    Isoniazid, INH; Rifampin: (Major) Some manufacturers recommend avoiding the coadministration of rifampin and proton pump inhibitors (PPIs). Rifamycins induce multiple hepatic cytochrome P-450 enzymes, including those responsible for the metabolism of PPIs. A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If rifampin and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy.
    Itraconazole: (Moderate) Administer proton pump inhibitors at least 2 hours before or 2 hours after oral itraconazole to minimize the potential for an interaction. Because itraconazole oral bioavailability requires an acidic environment for solubility, its absorption may be decreased with concomitant administration of proton pump inhibitors.
    Ivacaftor: (Minor) Use caution when administering ivacaftor and omeprazole concurrently. Ivacaftor is an inhibitor of CYP3A and P-glycoprotein (Pgp). Co-administration of ivacaftor with CYP3A and Pgp substrates, such as omeprazole, can increase omeprazole exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined.
    Ketoconazole: (Major) Because ketoconazole requires an acidic pH for absorption, coadministration of a proton pump inhibitor (PPI) with ketoconazole can cause a notable decrease in the bioavailability of ketoconazole. PPIs have a prolonged duration of action, and staggering their time of administration with ketoconazole by several hours may not prevent the drug interaction. An alternative imidazole antifungal should be chosen if any of these gastrointestinal medications are required. If these drugs must be coadministered, administer ketoconazole tablets with an acidic beverage and closely monitor for breakthrough infection.
    Ketoprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Ketorolac: (Severe) Increased adverse gastrointestinal and other effects are possible if ketorolac is used with salicylates. In addition, concomitant administration of salicylates and ketorolac has resulted in a reduction in protein binding and a two-fold increase in unbound plasma concentrations of ketorolac. As a result, concomitant use of ketorolac and aspirin or any other NSAID is contraindicated. Because ketorolac can cause GI bleeding, inhibit platelet aggregation, and may prolong bleeding time, additive effects may be seen in patients receiving platelet inhibitors (e.g., aspirin), anticoagulants, or thrombolytic agents.
    Lansoprazole; Naproxen: (Major) Aspirin, ASA displaces naproxen from binding to albumin and increases naproxen excretion. Due to an increased free fraction of naproxen, increased adverse gastrointestinal effects are possible if naproxen is used with aspirin. In addition, further benefit with use of the two drugs as compared with aspirin monotherapy is not apparent, and antagonism of the irreversible platelet effect of aspirin occurs with concurrent use. The interaction appears to be due to competition at the enzyme active site. Patients who take low-dose aspirin for cardiovascular health may have the beneficial effects of aspirin on platelet function counteracted by naproxen. Concomitant aspirin and naproxen use is not recommended. The use of Naproxen with other salicylates can also lead to additive GI toxicity.
    Ledipasvir; Sofosbuvir: (Major) Solubility of ledipasvir decreases as gastric pH increases; thus, coadministration of ledipasvir; sofosbuvir with proton pump inhibitors (PPIs) may result in lower ledipasvir plasma concentrations. Ledipasvir can be administered with PPIs if given simultaneously under fasting conditions. The PPI dose should not exceed a dose that is comparable to omeprazole 20 mg/day.
    Lesinurad: (Moderate) Aspirin, ASA at doses higher than 325 mg per day may decrease the efficacy of lesinurad in combination with allopurinol. Aspirin at doses of 325 mg or less per day (i.e., for cardiovascular protection) does not decrease the efficacy of lesinurad and can be coadministered with lesinurad. (Moderate) Use lesinurad and omeprazole together with caution; omeprazole may increase the systemic exposure of lesinurad. Omeprazole is an inhibitor of CYP2C9 in vitro, and lesinurad is a CYP2C9 substrate.
    Lesinurad; Allopurinol: (Moderate) Aspirin, ASA at doses higher than 325 mg per day may decrease the efficacy of lesinurad in combination with allopurinol. Aspirin at doses of 325 mg or less per day (i.e., for cardiovascular protection) does not decrease the efficacy of lesinurad and can be coadministered with lesinurad. (Moderate) Use lesinurad and omeprazole together with caution; omeprazole may increase the systemic exposure of lesinurad. Omeprazole is an inhibitor of CYP2C9 in vitro, and lesinurad is a CYP2C9 substrate.
    Linagliptin: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents, such as linagliptin.
    Linagliptin; Metformin: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents, such as linagliptin.
    Lisinopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Loop diuretics: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with loop diuretics (furosemide, bumetanide, torsemide, and ethacrynic acid). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
    Loperamide: (Moderate) The plasma concentration of loperamide, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with omeprazole, a P-gp inhibitor. If these drugs are used together, monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest).
    Loperamide; Simethicone: (Moderate) The plasma concentration of loperamide, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with omeprazole, a P-gp inhibitor. If these drugs are used together, monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest).
    Lopinavir; Ritonavir: (Moderate) Use caution when administering lopinavir; ritonavir and omeprazole concurrently. Ritonavir is an inhibitor of CYP3A and P-glycoprotein (P-gp), while lopinavir is a P-gp inhibitor. Coadministration of lopinavir; ritonavir with CYP3A and P-gp substrates, such as omeprazole, can increase omeprazole exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined. (Moderate) Use caution when administering ritonavir and omeprazole concurrently. Ritonavir is an inhibitor of CYP3A and P-glycoprotein (P-gp), while omeprazole is a CYP3A and P-gp substrate. Coadministration may increase omeprazole exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined.
    Lovastatin: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction.
    Lovastatin; Niacin: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction.
    Low Molecular Weight Heparins: (Moderate) An additive risk of bleeding may be seen in patients receiving a low molecular weight heparin in combination with other agents known to increase the risk of bleeding such as salicylates. Monitor clinical and laboratory response closely during concurrent use.
    Luliconazole: (Minor) Theoretically, luliconazole may increase the side effects of omeprazole, which is a CYP2C19 and a CYP3A4 substrate. Monitor patients for adverse effects of omeprazole. In vitro, therapeutic doses of luliconazole inhibit the activity of CYP2C19 and CYP3A4 and small systemic concentrations may be noted with topical application, particularly when applied to patients with moderate to severe tinea cruris. No in vivo drug interaction trials were conducted prior to the approval of luliconazole.
    Lumacaftor; Ivacaftor: (Minor) Use caution when administering ivacaftor and omeprazole concurrently. Ivacaftor is an inhibitor of CYP3A and P-glycoprotein (Pgp). Co-administration of ivacaftor with CYP3A and Pgp substrates, such as omeprazole, can increase omeprazole exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined.
    Lumacaftor; Ivacaftor: (Moderate) Lumacaftor; ivacaftor may reduce the efficacy of omeprazole by substantially decreasing its systemic exposure. If used together, an omeprazole dosage adjustment may be necessary to obtain the desired therapeutic effect. Omeprazole is a CYP3A4 and CYP2C19 substrate; it is also a substrate and inhibitor of the P-glycoprotein (P-gp) transport system. Lumacaftor; ivacaftor is a strong inducer of CYP3A; in vitro data suggests is also has the potential to induce CYP2C19 and both induce and inhibit P-gp.
    Maraviroc: (Moderate) Use caution and closely monitor for increased adverse effects with the coadministration of maraviroc and omeprazole as increased maraviroc concentrations may occur. Maraviroc is a substrate of P-glycoprotein (P-gp); omeprazole is an inhibitor of P-gp. The effects of P-gp on the concentrations of maraviroc are unknown, although an increase in concentrations and thus, toxicity, are possible.
    Measles Virus; Mumps Virus; Rubella Virus; Varicella Virus Vaccine, Live: (Major) No adverse events associated with the use of salicylates after varicella vaccination have been reported. However, the manufacturer of varicella virus vaccine live recommends the avoidance of salicylates or aspirin, ASA use for 6 weeks after vaccination. Reye's syndrome, which exclusively affects children under 15 years old, has been associated with aspirin use following active varicella infection. Vaccination with close clinical monitoring is recommended for children who require therapeutic aspirin, ASA therapy; according to the CDC the use of attenuated, live varicella virus vaccine is thought to present less risk than natural varicella disease to such children.
    Meclofenamate Sodium: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Mefenamic Acid: (Major) Increased adverse gastrointestinal (GI) effects are possible if mefenamic acid is used with salicylates. In addition, concomitant administration of salicylates and mefenamic acid may result in an increase in unbound plasma concentrations of either drug, which could result in greater adverse effects. In general, concomitant use of aspirin and mefenamic acid is not recommended.
    Mefloquine: (Moderate) Proton pump inhibitors (PPIs) may increase plasma concentrations of mefloquine. Patients on chronic mefloquine therapy might be at increased risk of adverse reactions, especially patients with a neurological or psychiatric history.
    Meglitinides: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of antidiabetic agents. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose or use of greater than maximum recommended daily dosages, salicylates can cause either hypoglycemia or hyperglycemia. Large doses of aspirin should be used cautiously in patients who receive antidiabetic agents.
    Meloxicam: (Major) Additive adverse gastrointestinal (GI) effects are possible if meloxicam is used with salicylates (e.g., aspirin). The concurrent use of aspirin and a nonsteroidal anti-inflammatory drug (NSAID) does increase the risk of serious gastrointestinal events. Concomitant administration of aspirin, ASA (3000 mg/day) to healthy volunteers increased the meloxicam AUC by 10% and increased the meloxicam peak plasma concentrations by 24%. Because of its lack of platelet effects, meloxicam is not a substitute for aspirin for cardiovascular prophylaxis.
    Mepenzolate: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Mephobarbital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Mesalamine, 5-ASA: (Major) The dissolution of the coating on mesalamine extended-release capsules (Apriso) and the delayed-release tablets (Lialda) is dependent on pH. Avoid coadministration with drugs that raise gastric pH like proton pump inhibitors.
    Metformin: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control.
    Metformin; Pioglitazone: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates can cause hyperglycemia and glycosuria.
    Metformin; Repaglinide: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of antidiabetic agents. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose or use of greater than maximum recommended daily dosages, salicylates can cause either hypoglycemia or hyperglycemia. Large doses of aspirin should be used cautiously in patients who receive antidiabetic agents.
    Metformin; Rosiglitazone: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates can cause hyperglycemia and glycosuria.
    Metformin; Saxagliptin: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates can indirectly increase insulin secretion, decreasing blood glucose concentrations. In large doses, salicylates may cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving saxagliptin.
    Metformin; Sitagliptin: (Moderate) Large doses of salicylates may enhance hypoglycemia in diabetic patients via inhibition of prostaglandin synthesis. If these agents are administered or discontinued in patients receiving oral antidiabetic agents, patients should be monitored for hypoglycemia or loss of blood glucose control. (Moderate) Salicylates can indirectly increase insulin secretion, decreasing blood glucose concentrations. In large doses, salicylates may cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Methazolamide: (Major) Avoid the coadministration of high-dose salicylates and carbonic anhydrase inhibitors, like methazolamide, whenever possible. The combination yielded reports of anorexia, tachypnea, lethargy, metabolic acidosis, coma, and death. The mechanism appears to be accumulation of the carbonic anhydrase inhibitor, resulting in increased CNS depression and metabolic acidosis. The acidosis may allow greater CNS penetration of the salicylate.
    Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Methohexital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Methotrexate: (Severe) Caution should be exercised when salicylates are given in combination with methotrexate. Since both are weak acids, salicylates can impair the renal secretion of methotrexate and increase the risk of methotrexate toxicity. Salicylates can also displace methotrexate from protein-binding sites. Although the risk for drug interactions with methotrexate is greatest during high-dose methotrexate therapy, it has been recommended that any of these drugs be used cautiously with methotrexate even when methotrexate is used in low doses for the treatment of rheumatoid arthritis. A significantly higher incidence of leukopenia has been reported in patients taking aspirin during methotrexate therapy. In addition, large doses of salicylates (>= 3 to 4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding. (Major) Use caution when administering high-dose methotrexate to patients receiving proton pump inhibitors (PPIs); a temporary withdrawal of the PPI should be considered in some patients receiving high-dose methotrexate. Case reports and published population pharmacokinetic studies suggest that concomitant use of some PPIs such as omeprazole, pantoprazole, or esomeprazole with methotrexate primarily at high dose may elevate and prolong serum methotrexate concentrations and/or its metabolite hydroxymethotrexate, which may lead to methotrexate toxicities. In two of these cases, delayed methotrexate elimination was observed when high-dose methotrexate was coadministered with PPIs but was not observed when methotrexate was coadministered with ranitidine. However, no formal drug interaction studies of methotrexate with ranitidine have been conducted. Among adults who received high-dose methotrexate (median dose of 3500 mg/m2, range of 1000-5000 mg/m2), coadministration of PPIs such as omeprazole, lansoprazole, or rabeprazole was identified as a risk factor for delayed methotrexate elimination with an OR of 2.65 (95% confidence interval 1.036.82). The interaction may be partially explained by the inhibitory effects of PPIs on breast cancer resistance protein (BCRP, ABCG2) -mediated methotrexate transport. Altered methotrexate elimination may not be present or problematic among patients who receive lower methotrexate doses. For example, coadministration of lansoprazole 30 mg daily and naproxen 500 mg twice daily for 7 days to recipients of stable oral methotrexate doses (7.515 mg/week) for a minimum of 3 months did not alter the pharmacokinetic profile of either methotrexate or 7-hydroxymethotrexate. Specifically, the peak plasma concentration and area under the plasma concentration-time curve of methotrexate and 7-hydroxymethotrexate were within the 0.80 to 1.25 boundaries.
    Methscopolamine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Methyclothiazide: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Methylphenidate: (Minor) The effects of gastrointestinal pH alterations on the absorption of extended-release methylphenidate (Ritalin LA) have not been studied. Per the manufacturer of extended-release methylphenidate, the modified release characteristics are pH-dependent. It is possible that the administration of proton pump inhibitors (PPIs) or other acid suppressants could alter the release of extended-release methylphenidate, resulting in reduced or increased absorption. Patients receiving a PPI should be monitored for adverse effects and reduced therapeutic efficacy of extended-release methylphenidate.
    Methylsulfonylmethane, MSM: (Moderate) It would be prudent for patients who take aspirin to avoid methylsulfonylmethane, MSM. Monitor patients who choose to take MSM while on aspirin therapy for bleeding. Patients taking MSM and anticoagulant drugs have reported increased anticoagulant effects such as increased bruising or blood in the stool.
    Metoclopramide: (Minor) Metoclopramide can increase the rate or extent of absorption of aspirin because of accelerated gastric emptying, which increases the contact time with the small bowel where this drug is absorbed.
    Metolazone: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Midazolam: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as midazolam. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Mitotane: (Moderate) Use caution if mitotane and omeprazole are used concomitantly, and monitor for decreased efficacy of omeprazole and a possible change in dosage requirements. Mitotane is a strong CYP3A4 inducer and omeprazole is a CYP3A4 substrate; coadministration may result in decreased plasma concentrations of omeprazole.
    Modafinil: (Minor) Some manufacturers recommend avoiding the coadministration of hepatic cytochrome P-450 enzyme inducers and proton pump inhibitors (PPIs). Modafinil induces hepatic cytochrome P-450 enzyme CYP3A4 but significantly inhibits CYP2C19; both of these enzymes are responsible for the metabolism of PPIs. It is unclear that the theoretical interaction would result in a net increase or decrease in PPI action. If modafinil and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy, or for signs of PPI side effects.
    Moexipril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Montelukast: (Moderate) Caution is advised when administering montelukast with CYP2C9 inhibitors such as omeprazole. In vitro studies using human liver microsomes indicate that CYP2C9 is involved in the metabolism of montelukast. In theory, it is possible that potent CYP2C9 inhibitors would reduce the clearance of montelukast.
    Muromonab-CD3: (Minor) Due to aspirin's effect on platelet aggregation and GI mucosa, aspirin should be used cautiously in patients with thrombocytopenia following treatment with antineoplastic agents due to an increased risk of bleeding.
    Mycophenolate: (Moderate) Concomitant administration of proton pump inhibitors (PPIs) with mycophenolate mofetil (Cellcept) appears to reduce MPA exposure AUC-12h (25.8 +/- 6.4 mg/L x h with omeprazole vs. 33.3 +/- 11.5 mg//L x h without omeprazole); however, the interaction does not appear to exist with mycophenolate sodium delayed-release tablets (Myfortic). Reduced systemic exposure of MPA after mycophenolate mofetil in the presence of a PPI appears to be due to impaired absorption of mycophenolate mofetil which may occur because of incomplete dissolution of mycophenolate mofetil in the stomach at elevated pH. The clinical significance of reduced MPA exposure is unknown; however patients should be evaluated periodically if mycophenolate mofetil is administered with a PPI. Of note, MPA concentrations appear to be reduced in the initial hours after mycophenolate mofetil receipt but increase later in the dosing interval because of enterohepatic recirculation. A second peak in the concentration-time profile of MPA is observed 612 hours after dosing due to enterohepatic recirculation. For example, the 12-hour plasma concentrations of MPA were similar among patients who received mycophenolate mofetil with or without omeprazole. The biphasic plasma concentration-time course of MPA due to extensive enterohepatic circulation hampers therapeutic drug monitoring of MPA. Drug exposure as measured by AUC-12h is the best estimator for the clinical effectiveness of mycophenolate, but measurement of full-dose interval MPA AUC-12h requires collection of multiple samples over a 12-hour period; MPA predose concentrations correlate poorly with MPA AUC-12h. The interaction does not appear to exist with Mycophenolate sodium (Myfortic). (Moderate) Mycophenolic acid is more than 98% bound to albumin. Concurrent use of mycophenolate with salicylates can decrease the protein binding of mycophenolic acid resulting in an increase in the free fraction of MPA. Patients should be observed for increased clinical effects from mycophenolate as well as additive adverse effects.
    Nabumetone: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Nafcillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Naproxen: (Major) Aspirin, ASA displaces naproxen from binding to albumin and increases naproxen excretion. Due to an increased free fraction of naproxen, increased adverse gastrointestinal effects are possible if naproxen is used with aspirin. In addition, further benefit with use of the two drugs as compared with aspirin monotherapy is not apparent, and antagonism of the irreversible platelet effect of aspirin occurs with concurrent use. The interaction appears to be due to competition at the enzyme active site. Patients who take low-dose aspirin for cardiovascular health may have the beneficial effects of aspirin on platelet function counteracted by naproxen. Concomitant aspirin and naproxen use is not recommended. The use of Naproxen with other salicylates can also lead to additive GI toxicity.
    Naproxen; Pseudoephedrine: (Major) Aspirin, ASA displaces naproxen from binding to albumin and increases naproxen excretion. Due to an increased free fraction of naproxen, increased adverse gastrointestinal effects are possible if naproxen is used with aspirin. In addition, further benefit with use of the two drugs as compared with aspirin monotherapy is not apparent, and antagonism of the irreversible platelet effect of aspirin occurs with concurrent use. The interaction appears to be due to competition at the enzyme active site. Patients who take low-dose aspirin for cardiovascular health may have the beneficial effects of aspirin on platelet function counteracted by naproxen. Concomitant aspirin and naproxen use is not recommended. The use of Naproxen with other salicylates can also lead to additive GI toxicity.
    Naproxen; Sumatriptan: (Major) Aspirin, ASA displaces naproxen from binding to albumin and increases naproxen excretion. Due to an increased free fraction of naproxen, increased adverse gastrointestinal effects are possible if naproxen is used with aspirin. In addition, further benefit with use of the two drugs as compared with aspirin monotherapy is not apparent, and antagonism of the irreversible platelet effect of aspirin occurs with concurrent use. The interaction appears to be due to competition at the enzyme active site. Patients who take low-dose aspirin for cardiovascular health may have the beneficial effects of aspirin on platelet function counteracted by naproxen. Concomitant aspirin and naproxen use is not recommended. The use of Naproxen with other salicylates can also lead to additive GI toxicity.
    Nateglinide: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of antidiabetic agents. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose or use of greater than maximum recommended daily dosages, salicylates can cause either hypoglycemia or hyperglycemia. Large doses of aspirin should be used cautiously in patients who receive antidiabetic agents.
    Nelfinavir: (Major) Use of proton pump inhibitors with nelfinavir is not recommended. Coadministration may result in decreased nelfinavir exposure, subtherapeutic antiretroviral activity, and possibility resistant HIV mutations. In one study, concurrent use of nelfinavir with omeprazole resulted in decreased nelfinavir AUC, Cmax, and Cmin by 36%, 37%, and 39%, respectively.
    Neratinib: (Major) Avoid concomitant use of neratinib with proton pump inhibitors due to decreased efficacy of neratinib. Concomitant use with lansoprazole decreased neratinib exposure by 65%. Concomitant use with other pH lowering agents was not studied, but a decrease in the AUC of neratinib is considered likely.
    Niacin; Simvastatin: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction.
    Nilotinib: (Major) Avoid the concomitant use of nilotinib and proton pump inhibitors (PPIs), as PPIs may cause a reduction in nilotinib bioavailability. Nilotinib displays pH-dependent solubility with decreased solubility at a higher pH. PPIs inhibit gastric acid secretion and elevate the gastric pH. Administration of a single 400-mg nilotinib dose with multiple oral doses of esomeprazole 40 mg/day reduced the nilotinib AUC by 34% in a study in healthy subjects. Increasing the dose is unlikely to compensate for the loss of nilotinib exposure; additionally, separating the administration of these agents may not eliminate the interaction as PPIs affect the pH of the upper GI tract for an extended period of time. (Moderate) Nilotinib can cause thrombocytopenia. Large doses of salicylates (3 to 4 g/day or higher) can cause hypoprothrombinemia, an additional risk factor for bleeding.
    Nintedanib: (Moderate) Omeprazole is a moderate inhibitor of P-glycoprotein (P-gp) and nintedanib is a P-gp substrate. Coadministration may increase the concentration and clinical effect of nintedanib. If concomitant use of omeprazole and nintedanib is necessary, closely monitor for increased nintedanib side effects including gastrointestinal toxicity, elevated liver enzymes, and hypertension. A dose reduction, interruption of therapy, or discontinuation of therapy may be necessary.
    Nitazoxanide: (Moderate) The active metabolite of nitazoxanide, tizoxanide, is highly bound to plasma proteins. Caution should be exercised when administering nitazoxanide concurrently with other highly plasma protein-bound drugs with narrow therapeutic indices because competition for binding sites may occur.
    Nitroglycerin: (Moderate) When coadministered with aspirin, ASA (doses between 500 mg and 1000 mg), the maximum plasma concentration (Cmax) and exposure (AUC) of a single nitroglycerin dose is increased by 67% and 73%, respectively. Additionally, limited data suggest that patients receiving aspirin, ASA in high doses can exhibit an exaggerated response to sublingual nitroglycerin. Although hypotension and tachycardia were more significant during concomitant therapy, no special precautions appear necessary. The pharmacologic effects of 0.4% nitroglycerin rectal ointment may also be enhanced when administered concomitantly with aspirin, ASA; therefore, close clinical monitoring is advised.
    Obeticholic Acid: (Minor) Concurrent administration of 20 mg omeprazole as a single dose with obeticholic acid 10 mg once daily resulted in a 32% increase in omeprazole AUC and a 33% increase in omeprazole Cmax. The clinical significance of this interaction is unknown. Even though omeprazole is a CYPC19 substrate, obeticholic acid is not expected to inhibit the CYPC19 isoenzyme. The mechanism of this interaction has not been described.
    Octreotide: (Minor) The effectiveness of proton pump inhibitors may be decreased if given with other antisecretory agents, such as octreotide. Proton pump inhibitors inhibit only actively secreting H+-pumps. Antacids may be used while taking esomeprazole.
    Omacetaxine: (Major) Avoid the concomitant use of omacetaxine and aspirin, ASA when the platelet count is less than 50,000 cells/microliter due to an increased risk of bleeding. Also, aspirin may mask signs of infection such as fever and pain in patients following treatment with antineoplastic agents or immunosuppressives. Aspirin, ASA should be used with caution in patients receiving immunosuppressive therapy. Special consideration should be given to myelosuppressed patients prior to receiving aspirin.
    Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Dosage adjustments of omeprazole may be required during concomitant administration with dasabuvir; ombitasvir; paritaprevir; ritonavir. Use of these drugs together results in decreased omeprazole serum concentrations. Monitor for decreasing efficacy and consider increasing the omeprazole dose if needed; however, adult doses should be limited to no more than 40 mg/day. The dose should be re-adjusted after completion of the 4-drug hepatitis C treatment regimen. (Moderate) Use caution when administering ritonavir and omeprazole concurrently. Ritonavir is an inhibitor of CYP3A and P-glycoprotein (P-gp), while omeprazole is a CYP3A and P-gp substrate. Coadministration may increase omeprazole exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined.
    Omeprazole; Sodium Bicarbonate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
    Oritavancin: (Moderate) Administration of oritavancin, a weak inhibitor of CYP2C19, with omeprazole resulted in a 15% increase in the ratio of omeprazole to 5-OH-omeprazole concentrations in the plasma. Monitor patients for omeprazole toxicities, such as headache or gastrointestinal distress, if these drugs are administered concurrently.
    Oxacillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Oxaprozin: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Oxcarbazepine: (Minor) Some manufacturers recommend avoiding the coadministration of hepatic cytochrome P-450 enzyme inducers and proton pump inhibitors (PPIs). Oxcarbazepine and its MHD metabolite induce hepatic cytochrome P-450 enzyme CYP3A4 but potently display dose-dependent CYP2C19 inhibition; both enzymes are involved in the metabolism of PPIs. It is unclear that the theoretical interaction would result in a net increase or decrease in PPI action. If oxcarbazepine and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy, or for signs of PPI side effects.
    Oxybutynin: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Paroxetine: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
    Pazopanib: (Major) Pazopanib displays pH-dependent solubility with decreased solubility at a higher pH. The concomitant use of pazopanib and proton pump inhibitors (PPIs) that elevate the gastric pH may reduce the bioavailability of pazopanib. In a study of patients with solid tumors, the AUC and Cmax of pazopanib were decreased by approximately 40% when coadministered with esomeprazole. If a drug is needed to raise the gastric pH, consider use of a short-acting antacid; separate antacid and pazopanib dosing by several hours.
    Penicillin G Benzathine: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Penicillin G Benzathine; Penicillin G Procaine: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Penicillin G Procaine: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Penicillin G: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Penicillin V: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Penicillins: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Pentobarbital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Pentosan: (Moderate) Pentosan is a weak anticoagulant. Pentosan has 1/15 the anticoagulant activity of heparin. An additive risk of bleeding may be seen in patients receiving other platelet inhibitors (e.g. aspirin, ASA) in combination with pentosan. Also, large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding.
    Pentoxifylline: (Moderate) The concomitant administration of platelet inhibitor with pentoxifylline in the treatment of intermittent claudication has not been evaluated and should be approached with caution, due to the potential for synergistic effects.
    Perindopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Perindopril; Amlodipine: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Phenobarbital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Phentermine; Topiramate: (Moderate) Concurrent use of topiramate and drugs that affect platelet function such as aspirin, ASA and other salicylates may increase the risk of bleeding. In a pooled analysis of placebo-controlled trials, bleeding was more frequently reported in patients receiving topiramate (4.5%) compared to placebo (2 to 3%). In those with severe bleeding events, patients were often taking drugs that cause thrombocytopenia or affect platelet function or coagulation.
    Phenytoin: (Moderate) Omeprazole can exhibit a dose-dependent inhibition of the hepatic cytochrome P-450 enzyme system, specifically CYP2C19. Because of this, omeprazole can interfere with the clearance of drugs metabolized via this pathway, such as phenytoin or fosphenytoin, resulting in increased phenytoin plasma concentrations. Clinical data do not exist, but an interaction is possible based on the known pathways of elimination. Patients should be monitored carefully for signs of increased drug effect if omeprazole is used with these drugs. In addition, some manufacturers recommend avoiding the coadministration of hepatic cytochrome P-450 enzyme inducers and proton pump inhibitors (PPIs). Phenytoin induces hepatic cytochrome P-450 enzymes, including those responsible for the metabolism of PPIs (e.g., CYP3A4, CYP2C19). A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If phenytoin and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy. (Minor) Large doses of salicylates can displace phenytoin from plasma protein-binding sites. Although increased serum concentrations of unbound phenytoin may lead to phenytoin toxicity, the liver may also more rapidly clear unbound drug. Displacement of phenytoin from binding sites can lead to a decrease in the total phenytoin serum concentration. Close monitoring for excessive phenytoin toxicity or decreased phenytoin efficacy is recommended.
    Phosphorated Carbohydrate Solution: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Phosphorus Salts: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Phosphorus: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Pioglitazone: (Moderate) Salicylates can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates can cause hyperglycemia and glycosuria.
    Piperacillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Piperacillin; Tazobactam: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Piroxicam: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Pneumococcal Vaccine, Polyvalent: (Moderate) Concomitant administration of antipyretics, such as aspirin, ASA, may decrease an individual's immunological response to the pneumococcal vaccine. A post-marketing study conducted in Poland using a non-US vaccination schedule (2, 3, 4, and 12 months of age) evaluated the impact of prophylactic oral acetaminophen on antibody responses to Prevnar 13. Data show that acetaminophen, given at the time of vaccination and then dosed at 6 to 8 hour intervals for 3 doses on a scheduled basis, reduced the antibody response to some serotypes after the third dose of Prevnar 13 when compared to the antibody responses of infants who only received antipyretics 'as needed' for treatment. However, reduced antibody responses were not observed after the fourth dose of Prevnar 13 with prophylactic acetaminophen.
    Polyethylene Glycol; Electrolytes; Bisacodyl: (Minor) The concomitant use of bisacodyl oral tablets with drugs that raise gastric pH like proton pump inhibitors can cause the enteric coating of the bisacodyl tablets to dissolve prematurely, leading to possible gastric irritation or dyspepsia. When taking bisacodyl tablets, it is advisable to avoid PPIs within 1 hour before or after the bisacodyl dosage.
    Polymyxins: (Major) Theoretically, the chronic coadministration of these drugs may increase the risk of developing nephrotoxicity, even in patients who have normal renal function. Monitor patients for changes in renal function if these drugs are coadministered. Since colistimethate sodium is eliminated by the kidney, coadministration with other potentially nephrotoxic drugs, including salicylates, may increase serum concentrations of either drug.
    Ponatinib: (Major) Ponatinib displays pH-dependent aqueous solubility; therefore, concomitant use of ponatinib and proton-pump inhibitors, such as omeprazole, may result in decreased bioavailability and plasma exposure of ponatinib. Avoid concomitant use of ponatinib with proton-pump inhibitors unless the benefit outweighs the possible risk of ponatinib underexposure. If the use of both agents is necessary, monitor patients for signs of reduced efficacy. Additionally, ponatinib may increase the plasma concentration of a P-gp substrate such as, omeprazole.
    Porfimer: (Major) Agents that inhibit prostaglandin synthesis such as aspirin, ASA could decrease the efficacy of porfimer photodynamic therapy (PDT).
    Posaconazole: (Major) The concurrent use of posaconazole oral suspension and proton pump inhibitors (PPIs) should be avoided, if possible, due to the potential for decreased posaconazole efficacy. If used in combination, closely monitor for breakthrough fungal infections. PPIs increase gastric pH, resulting in decreased posaconazole absorption and lower posaconazole plasma concentrations. When a single 400 mg dose of posaconazole oral suspension was administered with esomeprazole (40 mg PO daily), the mean reductions in Cmax were 46% and the mean reductions in AUC were 32% for posaconazole. The pharmacokinetics of posaconazole delayed-release tablets are not significantly affected by PPIs. Additionally, posaconazole is a potent inhibitor of CYP3A4, an isoenzyme partially responsible for the metabolism of many PPIs (dexlansoprazole, esomeprazole, lansoprazole, omeprazole, pantoprazole, and rabeprazole). Coadministration may result in increased plasma concentration of the PPIs.
    Potassium Citrate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
    Potassium Phosphate; Sodium Phosphate: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Potassium Salts: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
    Potassium-sparing diuretics: (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. This combination may cause hyperkalemia.
    Pramlintide: (Moderate) Salicylates can indirectly increase insulin secretion, and thus decrease blood glucose concentrations. In large doses, salicylates may cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Prasterone, Dehydroepiandrosterone, DHEA (Dietary Supplements): (Moderate) Prasterone, dehydroepiandrosterone, DHEA appears to have antiplatelet effects, which may prolong bleeding times. Because of these potential, varied effects on coagulation, patients receiving DHEA concurrently with aspirin, should be monitored for side effects or the need for dosage adjustments.
    Prasterone, Dehydroepiandrosterone, DHEA (FDA-approved): (Moderate) Prasterone, dehydroepiandrosterone, DHEA appears to have antiplatelet effects, which may prolong bleeding times. Because of these potential, varied effects on coagulation, patients receiving DHEA concurrently with aspirin, should be monitored for side effects or the need for dosage adjustments.
    Prasugrel: (Moderate) Although indicated for concomitant use, both prasugrel and aspirin are associated with bleeding. Aspirin 150 mg did not alter prasugrel-mediated inhibition of platelet aggregation; however, bleeding time was increased compared to either drug alone. Monitor for bleeding during concomitant therapy.
    Primidone: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Probenecid: (Severe) Concurrent use of probenecid and salicylates is contraindicated. The uricosuric actions of probenecid are inhibited by salicylates. When probenecid is used to treat hyperuricemia or gout, do not administer with salicylates.
    Propantheline: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Psyllium: (Moderate) Psyllium can interfere with the absorption of certain oral drugs if administered concomitantly. For example, psyllium fiber can adsorb salicylates. Per the psyllium manufacturers, administration of other prescribed oral drugs should be separated from the administration of psyllium by at least 2 hours.
    Quazepam: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as quazepam. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Quinapril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Ramipril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Red Yeast Rice: (Moderate) Caution is warranted when combining red yeast rice (structurally similar to lovastatin) with omeprazole. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product.
    Repaglinide: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of antidiabetic agents. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose or use of greater than maximum recommended daily dosages, salicylates can cause either hypoglycemia or hyperglycemia. Large doses of aspirin should be used cautiously in patients who receive antidiabetic agents.
    Ribociclib: (Minor) Use caution if coadministration of ribociclib with omeprazole is necessary, as the systemic exposure of omeprazole may be increased resulting in increase in treatment-related adverse reactions. Ribociclib is a moderate CYP3A4 inhibitor and omeprazole is a CYP3A4 substrate.
    Ribociclib; Letrozole: (Minor) Use caution if coadministration of ribociclib with omeprazole is necessary, as the systemic exposure of omeprazole may be increased resulting in increase in treatment-related adverse reactions. Ribociclib is a moderate CYP3A4 inhibitor and omeprazole is a CYP3A4 substrate.
    Rifabutin: (Major) Some manufacturers recommend avoiding the coadministration of rifampin and proton pump inhibitors (PPIs). Rifamycins induce multiple hepatic cytochrome P-450 enzymes, including those responsible for the metabolism of PPIs. A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If rifampin and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy.
    Rifampin: (Major) Some manufacturers recommend avoiding the coadministration of rifampin and proton pump inhibitors (PPIs). Rifamycins induce multiple hepatic cytochrome P-450 enzymes, including those responsible for the metabolism of PPIs. A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If rifampin and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy.
    Rifamycins: (Major) Some manufacturers recommend avoiding the coadministration of rifampin and proton pump inhibitors (PPIs). Rifamycins induce multiple hepatic cytochrome P-450 enzymes, including those responsible for the metabolism of PPIs. A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If rifampin and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy.
    Rifapentine: (Major) Some manufacturers recommend avoiding the coadministration of rifampin and proton pump inhibitors (PPIs). Rifamycins induce multiple hepatic cytochrome P-450 enzymes, including those responsible for the metabolism of PPIs. A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If rifampin and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy.
    Rifaximin: (Moderate) Although the clinical significance of this interaction is unknown, concurrent use of rifaximin, a P-glycoprotein (P-gp) substrate, and omeprazole, a P-gp inhibitor, may substantially increase the systemic exposure to rifaximin; caution is advised if these drugs must be administered together. During one in vitro study, coadministration with cyclosporine, a potent P-gp inhibitor, resulted in an 83-fold and 124-fold increase in the mean Cmax and AUC of rifaximin, respectively. In patients with hepatic impairment, the effects of reduced metabolism and P-gp inhibition may further increase exposure to rifaximin.
    Rilpivirine: (Severe) Concurrent use of proton pump inhibitors and rilpivirine is contraindicated; when these drugs are coadministered, there is a potential for treatment failure and/or the development of rilpivirine or NNRTI resistance. Proton pump inhibitors inhibit secretion of gastric acid by proton pumps thereby increasing the gastric pH; for optimal absorption, rilpivirine requires an acidic environment. Coadministration of a proton pump inhibitor and rilpivirine may result in decreased rilpivirine absorption/serum concentrations, which could cause impaired virologic response to rilpivirine.
    Riluzole: (Minor) The principal isozyme involved in the initial oxidative metabolism of riluzole is CYP1A2. CYP1A2 inducers, such as omeprazole could increase the rate of clearance of riluzole. Monitor for decreased effects of riluzole.
    Risedronate: (Major) Use of proton pump inhibitors (PPIs) with delayed-release risedronate tablets (Atelvia) is not recommended. Co-administration of drugs that raise stomach pH increases risedronate bioavailability due to faster release of the drug from the enteric coated tablet. This interaction does not apply to risedronate immediate-release tablets. In healthy subjects who received esomeprazole for 6 days, the Cmax and AUC of a single dose of risedronate delayed-release tablets (Atelvia) increased by 60% and 22%, respectively. PPIsare widely used and are frequently coadministered in users of oral bisphosphonates. A national register-based, open cohort study of 38,088 elderly patients suggests that those who use PPIs in conjunction with alendronate have a dose-dependent loss of protection against hip fracture. While causality was not investigated, the dose-response relationship noted during the study suggested that PPIs may reduce oral alendronate efficacy, perhaps through an effect on absorption or other mechanism, and therefore PPIs may not be optimal agents to control gastrointestinal complaints. Study results suggest that the interaction may occur across the class; however, other interactions have not been confirmed and data suggest that fracture protection is not diminished when risedronate is used with PPIs. A post hoc analysis of patients who took risedronate 5 mg daily during placebo-controlled clinical trials determined that risedronate significantly reduced the risk of new vertebral fractures compared to placebo, regardless of concomitant PPI use. PPI users (n = 240) and PPI non-users (n = 2489) experienced fracture risk reductions of 57% (p = 0.009) and 38% (p < 0.001), respectively.
    Ritonavir: (Moderate) Use caution when administering ritonavir and omeprazole concurrently. Ritonavir is an inhibitor of CYP3A and P-glycoprotein (P-gp), while omeprazole is a CYP3A and P-gp substrate. Coadministration may increase omeprazole exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined.
    Rituximab; Hyaluronidase: (Minor) Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients receiving these medications may require larger amounts of hyaluronidase for equivalent dispersing effect.
    Rivaroxaban: (Major) Salicylates such as aspirin are known to increase bleeding, and bleeding risk may be increased when these drugs are used concomitantly with rivaroxaban. The safety of long-term concomitant use of these drugs has not been studied. Promptly evaluate any signs or symptoms of blood loss if patients are treated concomitantly with salicylates. In a single-dose drug interaction study, no pharmacokinetic or pharmacodynamic interactions were observed after concomitant administration of naproxen or acetylsalicylic acid with rivaroxaban. (Minor) Coadministration of rivaroxaban and omeprazole may result in increases in rivaroxaban exposure and may increase bleeding risk. Omeprazole is an inhibitor of P-gp, and rivaroxaban is a substrate of P-gp. If these drugs are administered concurrently, monitor the patient for signs and symptoms of bleeding.
    Rosiglitazone: (Moderate) Salicylates can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates can cause hyperglycemia and glycosuria.
    Salicylic Acid: (Moderate) Concomitant use of salicylic acid with other drugs which may contribute to elevated serum salicylate levels (e.g., oral aspirin or other oral salicylates and other salicylate containing medications, such as sports injury creams) should be avoided. Concurrent use may result in excessive exposure to salicylic acid. Consider replacing aspirin therapy with an alternative non-steroidal anti-inflammatory agent that is not salicylate based where appropriate.
    Sapropterin: (Moderate) Caution is advised with the concomitant use of sapropterin and omeprazole as coadministration may result in increased systemic exposure of omeprazole. Omeprazole is a substrate for the drug transporter P-glycoprotein (P-gp); in vitro data show that sapropterin may inhibit P-gp. If these drugs are used together, closely monitor for increased side effects of omeprazole.
    Saquinavir: (Major) Coadministration with omeprazole results in significantly increased saquinavir concentrations. A similar interaction is expected with all proton pump inhibitors (PPIs). If saquinavir must be administered with PPIs, the patient should be closely monitored for saquinavir-related toxicities, including gastrointestinal symptoms, increased triglycerides, and deep vein thrombosis (DVT). Coadministration with omeprazole results in significantly increased saquinavir concentrations. In a small study, 18 healthy individuals received saquinavir 1000 mg (with ritonavir 100 mg) twice daily for 15 days; on days 11 through 15 omeprazole 40 mg was given once daily, which resulted in an 82% increase in the saquinavir AUC. A similar interaction is expected with all PPIs.
    Saxagliptin: (Moderate) Salicylates can indirectly increase insulin secretion, decreasing blood glucose concentrations. In large doses, salicylates may cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving saxagliptin.
    Scopolamine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Secobarbital: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Secretin: (Major) Discontinue use of proton pump inhibitors before administering secretin. Patients who are receiving proton pump inhibitors at the time of stimulation testing may be hyperresponsive to secretin stimulation, falsely suggesting gastrinoma. The time required for serum gastrin concentrations to return to baseline after discontinuation of a proton pump inhibitor is specific to the individual drug.
    Selective serotonin reuptake inhibitors: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
    Serotonin norepinephrine reuptake inhibitors: (Moderate) Platelet aggregation may be impaired by serotonin norepinephrine reuptake inhibitors (SNRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication (e.g., gastrointestinal bleeding, ecchymoses, epistaxis, hematomas, petechiae, hemorrhage) in patients receiving aspirin, ASA or other salicylates which affect hemostasis. Patients should be instructed to monitor for signs and symptoms of bleeding while taking an SNRI with medications which impair platelet function and to promptly report any bleeding events to the practitioner.
    Sertraline: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
    Sibutramine: (Moderate) According to the manufacturer, data from a pharmacokinetic study indicate that omeprazole decreases the metabolism of sibutramine and its active metabolites (M1 and M2). Increases in the serum concentration of sibutramine and its metabolites may lead to an increased risk of sibutramine-related adverse reactions. (Moderate) Bleeding events have occurred in patients receiving sibutramine. Serotonin reuptake inhibitors, like sibutramine, may inhibit serotonin uptake by platelets, impairing platelet function. Aspirin has antiplatelet effects that may be additive. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
    Simeprevir: (Minor) Simeprevir, a P-glycoprotein (P-gp) and a mild intestinal CYP3A4 inhibitor, may increase the side effects of omeprazole, which is a P-gp and CYP3A4 substrate. Additionally, increased side effects of simeprevir may occur as omeprazole is a P-gp inhibitor and simeprevir is a P-gp substrate in vitro. Monitor patients for adverse effects of omeprazole, such as GI events, and simeprevir, such as rash and phototoxicity.
    Simvastatin: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction.
    Simvastatin; Sitagliptin: (Moderate) Atorvastatin, lovastatin, and simvastatin are HMG-CoA reductase inhibitors (statins) recognized as substrates and inhibitors of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses prior to admission). Symptoms of weakness, shortness of breath, and chest pain coincided with the start of esomeprazole therapy. Due to the timing of symptom onset, clinicians suspected that esomeprazole likely increased atorvastatin plasma concentrations leading to rhabdomyolysis and further complications. Although competitive inhibition of CYP isoenzyme metabolism could have played a minor role in the interaction, the main pathway was thought to be competitive P-gp inhibition. Caution is therefore warranted when combining atorvastatin, lovastatin, red yeast rice (structurally similar to lovastatin), or simvastatin with esomeprazole, lansoprazole, omeprazole, or pantoprazole. Substituting with dexlansoprazole or rabeprazole may represent a safer alternative. Treatment with pravastatin, fluvastatin, and rosuvastatin may also decrease the risk of a P-gp interaction. (Moderate) Salicylates can indirectly increase insulin secretion, decreasing blood glucose concentrations. In large doses, salicylates may cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Sitagliptin: (Moderate) Salicylates can indirectly increase insulin secretion, decreasing blood glucose concentrations. In large doses, salicylates may cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
    Sodium Bicarbonate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
    Sodium Hyaluronate, Hyaluronic Acid: (Moderate) Increased bruising or bleeding at the injection site may occur when using hyaluronate sodium with salicylates, especially if used within the 3 weeks prior to the procedure.
    Sodium Lactate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
    Sodium Thiosulfate; Salicylic Acid: (Moderate) Concomitant use of salicylic acid with other drugs which may contribute to elevated serum salicylate levels (e.g., oral aspirin or other oral salicylates and other salicylate containing medications, such as sports injury creams) should be avoided. Concurrent use may result in excessive exposure to salicylic acid. Consider replacing aspirin therapy with an alternative non-steroidal anti-inflammatory agent that is not salicylate based where appropriate.
    Sofosbuvir; Velpatasvir: (Major) Coadministration of proton pump inhibitors (PPIs) with velpatasvir is not recommended. If it is considered medically necessary to coadminister, velpatasvir should be administered with food and taken 4 hours before omeprazole 20 mg. Other PPIs have not been studied; however, it may be prudent to separate the administration of the other PPIs similarly. Velpatasvir solubility decreases as pH increases; therefore, drugs that increase gastric pH are expected to decrease the concentrations of velpatasvir, potentially resulting in loss of antiviral efficacy.
    Sofosbuvir; Velpatasvir; Voxilaprevir: (Major) Coadministration of proton pump inhibitors (PPIs) with velpatasvir is not recommended. If it is considered medically necessary to coadminister, velpatasvir should be administered with food and taken 4 hours before omeprazole 20 mg. Other PPIs have not been studied; however, it may be prudent to separate the administration of the other PPIs similarly. Velpatasvir solubility decreases as pH increases; therefore, drugs that increase gastric pH are expected to decrease the concentrations of velpatasvir, potentially resulting in loss of antiviral efficacy. (Moderate) Plasma concentrations of omeprazole, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with voxilaprevir, a P-gp inhibitor. Monitor patients for increased side effects if these drugs are administered concurrently.
    Solifenacin: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Sorafenib: (Minor) Sorafenib displays pH-dependent aqueous solubility; therefore, concomitant use of sorafenib and agents that increase the gastric pH, such as proton pump inhibitors (PPIs), may result in decreased plasma exposure of sorafenib. However, there was no clinically significant change in sorafenib exposure following a single oral dose of sorafenib administered after 5 days of omeprazole 40 mg/day. No sorafenib dosage adjustment is necessary.
    Spironolactone: (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. This combination may cause hyperkalemia.
    St. John's Wort, Hypericum perforatum: (Major) Coadministration of St. John's Wort, Hypericum perforatum (300 mg three times daily) for 14 days with a one time dose of omeprazole (20 mg) on day 15 resulted in decreased omeprazole plasma concentrations in healthy subjects. Omeprazole AUC was reduced by approximately 40% in both poor and extensive metabolizers of CYP2C19. The clinical significance of this interaction is not clear; however, due to variations in the amounts of active ingredient in herbal products, the magnitude of this interaction and the resultant clinical effect may vary. St. John's Wort induces both CYP3A4 and CYP2C19 dependent metabolism of omeprazole. Since, proton pump inhibitors (PPIs) are primary substrates of the CYP2C19 enzyme, patients taking St. John's Wort concomitantly with a PPI should be monitored for PPI efficacy.
    Sucralfate: (Minor) Proton pump inhibitors should be taken at least 30 minutes prior to sucralfate. Sucralfate has been shown to delay absorption and reduce the bioavailability of omeprazole by about 16%.
    Sulfinpyrazone: (Major) Salicylates should not be used concurrently with probenecid or sulfinpyrazone when these are used to treat hyperuricemia or gout because the uricosuric effect can be decreased. In addition, probenecid and sulfinpyrazone can decrease salicylic acid excretion leading to increased plasma concentration.
    Sulfonamides: (Minor) Due to high protein binding, salicylates could be displaced from binding sites, or could displace other highly protein-bound drugs such as sulfonamides. An enhanced effect of the displaced drug may occur.
    Sulfonylureas: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria.
    Sulindac: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Tacrolimus: (Moderate) Concomitant administration of omeprazole and tacrolimus may increase the serum concentrations of tacrolimus. (Moderate) Tacrolimus, in the absence of overt renal impairment, may adversely affect renal function. Care should be taken in using tacrolimus with other nephrotoxic drugs, such as salicylates.
    Tamoxifen: (Moderate) Theoretically, concomitant use may result in increased omeprazole side effects and decreased concentrations of the active metabolites of tamoxifen which can compromise efficacy; the clinical significance of this interaction is not known. Omeprazole is a CYP2C19 inhibitor and, in vitro, an inhibitor of CYP2C9. Tamoxifen is metabolized by CYP3A4, CYP2D6, and to a lesser extent by both CYP2C9 and CYP2C19, to other potent, active metabolites including endoxifen, which have up to 33 times more affinity for the estrogen receptor than tamoxifen. These metabolites are then inactivated by sulfotransferase 1A1 (SULT1A1). Additionally, omeprazole is a P-glycoprotein (P-gp) substrate; tamoxifen inhibits P-gp.
    Telaprevir: (Moderate) Close clinical monitoring is advised when administering omeprazole with telaprevir due to an increased potential for omeprazole-related adverse events. If omeprazole dose adjustments are made, re-adjust the dose upon completion of telaprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of omeprazole. Omeprazole is a substrate of the drug efflux transporter P-glycoprotein (PGP) and of the hepatic isoenzyme CYP3A4; telaprevir is an inhibitor of both the efflux protein and the isoenzyme. Coadministration may result in elevated omeprazole plasma concentrations.
    Telavancin: (Minor) Concurrent or sequential use of telavancin with drugs that inhibit renal prostaglandins such as salicylates may lead to additive nephrotoxicity. Closely monitor renal function and adjust telavancin doses based on calculated creatinine clearance.
    Telithromycin: (Minor) Concentrations of omeprazole may be increased with concomitant use of telithromycin. Omeprazole is a CYP3A4 and P-glycoprotein (PGP) substrate and telithromycin is a strong CYP3A4 inhibitor and potential PGP inhibitor. Patients should be monitored for increased side effects.
    Telotristat Ethyl: (Moderate) Use caution if coadministration of telotristat ethyl and omeprazole is necessary, as the systemic exposure of omeprazole may be decreased resulting in reduced efficacy; exposure to telotristat ethyl may also be increased. If these drugs are used together, monitor patients for suboptimal efficacy of omeprazole as well as an increase in adverse reactions related to telotristat ethyl. Consider increasing the dose of omeprazole if necessary. Omeprazole is a CYP3A4 substrate. The mean Cmax and AUC of another sensitive CYP3A4 substrate was decreased by 25% and 48%, respectively, when coadministered with telotristat ethyl; the mechanism of this interaction appears to be that telotristat ethyl increases the glucuronidation of the CYP3A4 substrate. Additionally, the active metabolite of telotristat ethyl, telotristat, is a substrate of P-glycoprotein (P-gp) and omeprazole is a P-gp inhibitor. Exposure to telotristat ethyl may increase.
    Temsirolimus: (Moderate) Use caution if coadministration of temsirolimus with omeprazole is necessary, and monitor for an increase in temsirolimus- and omeprazole-related adverse reactions. Temsirolimus is a P-glycoprotein (P-gp) substrate/inhibitor in vitro, while omeprazole is also a P-gp substrate/inhibitor. Pharmacokinetic data are not available for concomitant use of temsirolimus with P-gp inhibitors or substrates, but exposure to both omeprazole and temsirolimus (and active metabolite, sirolimus) is likely to increase.
    Tenofovir Alafenamide: (Moderate) Tenofovir-containing products should be avoided with concurrent or recent use of a nephrotoxic agent, such as salicylates. Tenofovir is primarily excreted via the kidneys by a combination of glomerular filtration and active tubular secretion. Coadministration of tenofovir alafenamide with drugs that are eliminated by active tubular secretion may increase concentrations of tenofovir and/or the co-administered drug. Drugs that decrease renal function may also increase concentrations of tenofovir. Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Monitor patients receiving concomitant nephrotoxic agents for changes in serum creatinine and phosphorus, and urine glucose and protein.
    Tenofovir, PMPA: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus. (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as omeprazole. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
    Thiazide diuretics: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics. Salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance. Salicylates may decrease the hyperuricemic effect of hydrochlorothiazide.
    Thiazolidinediones: (Moderate) Salicylates can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates can cause hyperglycemia and glycosuria.
    Thiopental: (Major) Avoid coadministration of omeprazole with barbiturates because it can result in decreased efficacy of omeprazole. Omeprazole is extensively metabolized in the liver by CYP2C19 and CYP3A4. Barbiturates induce CYP3A4 and CYP2C19.
    Thrombin Inhibitors: (Moderate) An additive risk of bleeding may be seen in patients receiving salicylates (e.g. aspirin, ASA) in combination with thrombin inhibitors. In addition, large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding. Nonsteroidal antiinflammatory drugs (NSAIDs) may also increase bleeding risk when given with argatroban because of their potential to cause GI bleeding or inhibit platelet aggregation.
    Thrombolytic Agents: (Moderate) Concurrent administration of thrombolytic agents and salicylates may further increase the serious risk of bleeding.
    Thyroid hormones: (Moderate) The use of proton pump inhibitors may result in decreased effectiveness of thyroid hormone therapy. Monitor clinically for signs and symptoms of hypothyroidism and altered response to thyroid hormone therapy. Periodically assess the TSH during use of these drugs together. Gastric acidity is an essential requirement for proper and adequate absorption of levothyroxine and other thyroid hormones. Proton pump inhibitors may cause hypochlorhydria, affect intragastric pH, and reduce thyroid hormone absorption.
    Ticagrelor: (Moderate) Avoid aspirin maintenance doses of more than 100 mg with concomitant ticagrelor. Maintenance doses of aspirin above 100 mg decreased ticagrelor effectiveness in a clinical trial. After the typical aspirin loading dose of 325 mg, use ticagrelor with an aspirin maintenance dose of 75 to 100 mg. Additionally, both drugs are associated with bleeding. Monitor for bleeding. (Moderate) Coadministration of ticagrelor and omeprazole may result in increased exposure to ticagrelor which may increase the bleeding risk. Ticagrelor is a P-glycoprotein (P-gp) substrate and omeprazole is a P-gp inhibitor. Based on drug information data with cyclosporine, no dose adjustment is recommended by the manufacturer of ticagrelor. Use combination with caution and monitor for evidence of bleeding.
    Ticarcillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Ticarcillin; Clavulanic Acid: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
    Ticlopidine: (Moderate) Use caution with coadministration of ticlopidine and aspirin. Ticlopidine potentiates the effect of aspirin on platelet aggregation. Safety of concomitant use of ticlopidine and aspirin has not been established beyond 30 days. Monitor for bleeding during concomitant therapy.
    Tinzaparin: (Moderate) An additive risk of bleeding may be seen in patients receiving a low molecular weight heparin in combination with other agents known to increase the risk of bleeding such as salicylates. Monitor clinical and laboratory response closely during concurrent use.
    Tipranavir: (Moderate) Caution should be used when administering tipranavir to patients receiving platelet inhibitors. In clinical trials, there have been reports of intracranial bleeding, including fatalities, in HIV infected patients receiving tipranavir as part of combination antiretroviral therapy. In many of these reports, the patients had other medical conditions (CNS lesions, head trauma, recent neurosurgery, coagulopathy, hypertension, or alcoholism/alcohol abuse) or were receiving concomitant medications, including platelet inhibitors, that may have caused or contributed to these events. (Moderate) Some manufacturers recommend avoiding the coadministration of hepatic cytochrome P-450 enzyme inducers and proton pump inhibitors (PPIs). Tipranavir markedly induces the hepatic cytochrome P-450 enzyme CYP2C19, an enzyme responsible for the metabolism of PPIs. However, since tipranavir is not given unless it is co-prescribed with ritonavir, a known marked enzyme inhibitor, a reduction in PPI metabolism may be unlikely to occur. A reduction in PPI concentrations may increase the risk of gastrointestinal (GI) adverse events such as GI bleeding. If tipranavir and PPIs must be used together, monitor the patient closely for signs and symptoms of GI bleeding or other signs and symptoms of reduced PPI efficacy.
    Tirofiban: (Moderate) Unless contraindicated, aspirin is used in combination with tirofiban. However, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy. (Minor) Patients who receive omeprazole concomitantly with tirofiban may have a higher rate of tirofiban clearance than patients who do not receive omeprazole. The clinical significance of this is unknown.
    Tocilizumab: (Minor) In vitro, tocilizumab has the potential to affect expression of multiple CYP enzymes including CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. It is expected that the formation of CYP450 enzymes could be normalized during tocilizumab receipt. In clinical trials of patients taking both omeprazole and tocilizumab, a decrease in omeprazole exposure (AUC) was noted. One week after a single tocilizumab dose, a 12 to 28% decrease in omeprazole exposure occurred. Use caution when using tocilizumab in combination with CYP-metabolized drugs where a decrease in effectiveness is undesirable.
    Tolazamide: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria.
    Tolbutamide: (Moderate) If salicylates and sulfonylureas are to be administered together, patients should be monitored for changes in glycemic control. Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of other antidiabetic agents. This mechanism may explain how salicylates can potentiate the clinical effects of sulfonylureas; however, displacement of sulfonylureas from protein binding sites has also been reported. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria.
    Tolmetin: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
    Tolterodine: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Topiramate: (Moderate) Concurrent use of topiramate and drugs that affect platelet function such as aspirin, ASA and other salicylates may increase the risk of bleeding. In a pooled analysis of placebo-controlled trials, bleeding was more frequently reported in patients receiving topiramate (4.5%) compared to placebo (2 to 3%). In those with severe bleeding events, patients were often taking drugs that cause thrombocytopenia or affect platelet function or coagulation.
    Topotecan: (Major) Avoid the concomitant use of omeprazole, a P-glycoprotein (P-gp) inhibitor, with oral topotecan, a P-gp substrate; P-gp inhibitors have less of an effect on intravenous topotecan and these may be coadministered with caution. The pharmacokinetics of topotecan are unchanged when coadministered with ranitidine, which is a possible alternative to acid suppression therapy if needed. If coadministration of omeprazole and oral topotecan is necessary, carefully monitor for increased toxicity of topotecan, including severe myelosuppression and diarrhea; this also applies to combination products containing omeprazole, such as amoxicillin; clarithromycin; omeprazole and omeprazole; sodium bicarbonate. In a pharmacokinetic cohort study, coadministration of oral topotecan with a potent P-gp inhibitor (n = 8) increased the Cmax and AUC of topotecan by 2 to 3 fold (p = 0.008); coadministration with intravenous topotecan (n = 8) increased total topotecan exposure by 1.2-fold (p = 0.02) and topotecan lactone by 1.1-fold (not significant).
    Torsemide: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with loop diuretics (furosemide, bumetanide, torsemide, and ethacrynic acid). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
    Trandolapril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
    Trandolapril; Verapamil: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
    Trazodone: (Moderate) The combined use of trazodone and salicylates that affect hemostasis may elevate the risk for an upper GI bleed. Trazodone may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of salicylates. Additionally, salicylates impair the gastric mucosa defenses by inhibiting prostaglandin formation. It would be prudent for clinicians to monitor the patient's clinical status closely if trazodone is added to or removed from the regimen of a patient stabilized on salicylate therapy.
    Treprostinil: (Moderate) When used concurrently with anticoagulants or platelet inhibitors, treprostinil may increase the risk of bleeding.
    Triamterene: (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. This combination may cause hyperkalemia.
    Triazolam: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as triazolam. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
    Trihexyphenidyl: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Tromethamine: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
    Trospium: (Moderate) The American College of Gastroenterology states that the effectiveness of proton pump inhibitors (PPIs) may be theoretically decreased if given with other antisecretory agents (e.g., anticholinergics). Proton pump inhibitors (PPIs) inhibit only actively secreting H+-pumps.
    Ulipristal: (Minor) In vitro data indicate that ulipristal may be an inhibitor of P-glycoprotein (P-gp) at clinically relevant concentrations. Thus, co-administration of ulipristal and P-gp substrates such as omeprazole may increase omeprazole concentrations. With single doses of ulipristal for emergency contraception it is not clear this interaction will have clinical consequence. In the absence of clinical data, co-administration of ulipristal (when given daily) and P-gp substrates is not recommended.
    Valproic Acid, Divalproex Sodium: (Moderate) Concurrent salicylate therapy can increase the free-fraction of valproic acid, causing possible valproic acid toxicity. Valproic acid levels should be monitored when these agents are used concomitantly.
    Vancomycin: (Minor) Due to the inhibition of renal prostaglandins by salicylates, concurrent use of salicylates and other nephrotoxic agents, such as vancomycin, may lead to additive nephrotoxicity.
    Vandetanib: (Minor) Use caution if coadministration of vandetanib with omeprazole is necessary, due to a possible increase in omeprazole-related adverse reactions. Omeprazole is partially a substrate of P-glycoprotein (P-gp). Coadministration with vandetanib increased the Cmax and AUC of digoxin, another P-gp substrate, by 29% and 23%, respectively.
    Varicella-Zoster Virus Vaccine, Live: (Major) No adverse events associated with the use of salicylates after varicella vaccination have been reported. However, the manufacturer of varicella virus vaccine live recommends the avoidance of salicylates or aspirin, ASA use for 6 weeks after vaccination. Reye's syndrome, which exclusively affects children under 15 years old, has been associated with aspirin use following active varicella infection. Vaccination with close clinical monitoring is recommended for children who require therapeutic aspirin, ASA therapy; according to the CDC the use of attenuated, live varicella virus vaccine is thought to present less risk than natural varicella disease to such children.
    Venetoclax: (Major) Avoid the concomitant use of venetoclax and omeprazole. Venetoclax is a substrate of CYP3A4 and P-glycoprotein (P-gp) and may be a P-gp inhibitor at therapeutic dose levels in the gut; omeprazole is a P-gp inhibitor and substrate. Consider alternative agents. If concomitant use of these drugs is required, reduce the venetoclax dosage by at least 50% (maximum dose of 200 mg/day) and consider administering omeprazole at least 6 hours before venetoclax. If omeprazole is discontinued, wait 2 to 3 days and then resume the recommended venetoclax dosage (or prior dosage if less). Monitor patients for signs and symptoms of venetoclax toxicity such as hematologic toxicity, GI toxicity, and tumor lysis syndrome. In a drug interaction study (n = 11), the venetoclax Cmax and AUC values were increased by 106% and 78%, respectively, when a P-gp inhibitor was co-administered in healthy subjects.
    Verapamil: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
    Vilazodone: (Moderate) Patients should be instructed to monitor for signs and symptoms of bleeding while taking vilazodone concurrently with salicylates or other platelet inhibitors and to promptly report any bleeding events to the practitioner. Platelet aggregation may be impaired by vilazodone due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication (e.g., gastrointestinal bleeding, ecchymoses, epistaxis, hematomas, petechiae, hemorrhage) in patients receiving platelet inhibitors (e.g., aspirin, cilostazol, clopidogrel, dipyridamole, ticlopidine, platelet glycoprotein IIb/IIIa inhibitors).
    Vincristine Liposomal: (Major) Omeprazole inhibits P-glycoprotein (P-gp), and vincristine is a P-gp substrate. Coadministration could increase exposure to vincristine; monitor patients for increased side effects if these drugs are given together.
    Vincristine: (Major) Omeprazole inhibits P-glycoprotein (P-gp), and vincristine is a P-gp substrate. Coadministration could increase exposure to vincristine; monitor patients for increased side effects if these drugs are given together.
    Vinorelbine: (Moderate) Use caution with concurrent use of omeprazole, a P-glycoprotein (P-gp) inhibitor, and vinorelbine, a P-gp substrate, as the metabolism of vinorelbine may be decreased; this may also apply to combination products containing omeprazole, including amoxicillin; clarithromycin; omeprazole and omeprazole; sodium bicarbonate. Monitor patients for an earlier onset and/or an increased severity of adverse effects including neurotoxicity and myelosuppression.
    Vorapaxar: (Moderate) Although indicated for concomitant use, both vorapaxar and aspirin are associated with bleeding. Monitor for bleeding during concomitant therapy.
    Voriconazole: (Moderate) Reduce the omeprazole dose by one-half when initiating voriconazole therapy in patients who are currently receiving omeprazole at doses of 40 mg/day or greater. Levels of omeprazole may increase by up to 2-fold due to CYP2C19 and CYP3A4 inhibition by voriconazole.
    Vortioxetine: (Moderate) Platelet aggregation may be impaired by vortioxetine due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication (e.g., gastrointestinal bleeding, ecchymoses, epistaxis, hematomas, petechiae, hemorrhage) in patients receiving aspirin, ASA or other salicylates. Bleeding events related to drugs that inhibit serotonin reuptake have ranged from ecchymosis to life-threatening hemorrhages. Patients should be instructed to monitor for signs and symptoms of bleeding while taking vortioxetine concurrently with aspirin products and to promptly report any bleeding events to the practitioner.
    Warfarin: (Major) Co-administration of aspirin and warfarin is associated with an increased risk of bleeding. Consider alternate therapy for aspirin for analgesic or antipyretic uses. If aspirin and warfarin are coadministered, monitor the patient for signs or symptoms of bleeding. Gastrointestinal irritation and impaired hemostasis secondary to platelet inhibition have been observed with relatively small doses of aspirin. In addition, aspirin may displace warfarin from protein binding sites leading to increased anticoagulation effects. Large doses (more than 3 to 4 g/day) of aspirin can cause hypoprothrombinemia, an additional risk factor for bleeding; hypoprothrombinemia has also been reported with aspirin doses less than 2 g/day. Lower doses (less than 100 mg) of aspirin are recommended for use in combination with aspirin for the prevention of cardiovascular events in specific cases, including in patients with mechanical mitral or aortic valve or atrial fibrillation after percutaneous coronary intervention or revascularization. The addition of warfarin to aspirin and a P2Y12 inhibitor in patients after ST-elevation myocardial infarction should be limited to situations where the risk of systemic or venous thromboembolism or stent thrombosis is considered to exceed that of bleeding. Data regarding the benefit vs. risk of combination therapy for other cardiovascular conditions remains unclear. (Moderate) Omeprazole (CYP2C19 inhibitor) can prolong the elimination of warfarin, particularly R-warfarin which is partially metabolized by CYP2C19. The combined use of omeprazole and warfarin has been associated with reports of increased INR and prothrombin time (PT). In addition, post-marketing reports of the combination of esomeprazole and warfarin have indicated elevations in PT. There have been reports of increased International Normalized Ratio (INR) and prothrombin time in patients receiving other proton pump inhibitors (PPIs) (including esomeprazole, lansoprazole, rabeprazole, and pantoprazole and warfarin concomitantly. It is prudent to monitor the INR more closely if these agents are combined with warfarin.
    Zafirlukast: (Minor) Coadministration of aspirin may increase plasma concentrations of zafirlukast. The potential clinical sequelae of increased zafirlukast concentrations are not known.
    Zonisamide: (Minor) Zonisamide is a weak inhibitor of P-glycoprotein (P-gp), and omeprazole is a substrate of P-gp. There is theoretical potential for zonisamide to affect the pharmacokinetics of drugs that are P-gp substrates. Use caution when starting or stopping zonisamide or changing the zonisamide dosage in patients also receiving drugs which are P-gp substrates.

    PREGNANCY AND LACTATION

    Pregnancy

    Aspirin and omeprazole are present in human milk. Limited data state the presence of aspirin in human milk at relative infant doses of 12.5% to 10.8% of the maternal weight-adjusted dosage. There are published case reports of breast-feeding infants whose mothers were exposed to aspirin during lactation developing metabolic acidosis, thrombocytopenia, and hemolysis. There are no data on the effect of aspirin on milk production. Limited data from a case report describes the presence of omeprazole in human milk at a relative infant dose of 0.9% of the maternal weight-adjusted dosage. There are not reports of adverse effects of omeprazole on the breastfed infant and no information on the effects of omeprazole on milk production. Due to the potential for serious adverse reactions, including metabolic acidosis, thrombocytopenia, hemolysis, or Reye's syndrome, advise patients that breast-feeding is not recommended during treatment with aspirin; omeprazole.

    MECHANISM OF ACTION

    Aspirin: Aspirin (acetylsalicylic acid) is an inhibitor of both prostaglandin synthesis and platelet aggregation. The activity of aspirin is due to its ability to inhibit cyclooxygenase (COX). Aspirin appears to inhibit COX through two pathways and seems to have a different mechanism of action than other salicylates. In comparison, salicylic acid has little or no ability to inhibit COX in vitro despite inhibiting prostaglandin synthesis at the site of inflammation in vivo. The exact mechanism of prostaglandin inhibition by salicylic acid is unclear; however, salicylates produce the majority of classic NSAID effects.
     
    Omeprazole: Omeprazole belongs to the class of GI antisecretory agents, the substituted benzimidazoles, which suppress gastric acid secretion by inhibiting the (H+, K+)-ATPase enzyme system of parietal cells. Following activation in an acidic pH, omeprazole binds irreversibly to the (H+, K+)-ATPase pump on the secretory surface of the parietal cell membrane. Subsequently, the secretion of hydrogen ions into the gastric lumen is inhibited. Omeprazole is characterized as a gastric acid pump inhibitor because it blocks the final step of gastric acid production. It inhibits both basal and stimulus-induced acid secretion.

    PHARMACOKINETICS

    Aspirin and omeprazole are administered orally.
    Aspirin: Acetylsalicylic acid (aspirin) is rapidly hydrolyzed to salicylic acid. Salicylic acid is conjugated in the liver to form salicyluric acid, a phenolic glucuronide, an acyl glucuronide, and a number of minor metabolites. Salicylic acid is widely distributed to all tissues in the body, with high concentrations in the liver, kidney, heart, and lungs. Protein binding of salicylic acid to albumin varies with serum salicylate and albumin concentrations. At salicylate levels of <= 100 mcg/ml, salicylic acid is approximately 90% bound to albumin. At higher concentrations (> 400 mcg/mL), approximately 75% is protein bound. The rate of aspirin elimination is constant in relation to plasma concentration. Renal excretion depends on urinary pH. As urinary pH rises above 6.5, the renal clearance of free salicylate increases from 5% to more than 80%. Following therapeutic doses, approximately 10% is excreted in the urine as salicylic acid, 75% as salicyluric acid, and 10% phenolic and 5% acyl glucuronides of salicylic acid. The half-life of salicylic acid after a dose of aspirin 325 mg; omeprazole 40 mg is 2.4 hours.
    Omeprazole: Extensively hepatic metabolism occurs, and the metabolites have minimal antisecretory activity. Omeprazole is 95% bound to plasma proteins. Extensive hepatic metabolism occurs, and the metabolites have minimal antisecretory activity. The plasma half-life in healthy patients is approximately 1 hour. The majority of the dose (approximately 77%) is excreted renally; the remainder of the dose is excreted in the feces.
    Serum gastrin levels increase during the initial 1 to 2 weeks of omeprazole therapy, and median increases in gastrin are greater than the increases produced by H2-receptor antagonists. Gastrin levels return to baseline within 1 to 2 weeks following discontinuance of therapy.
    Affected cytochrome P450 isoenzymes and drug transporters: CYP2C19, CYP3A4, CYP1A2, CYP2C9, P-gp
    Omeprazole is metabolized by the CYP2C19 isoenzyme (primary) and by the CYP3A4 isoenzyme (secondary). Omeprazole inhibits the CYP2C19 isoenzyme in vitro and in vivo and the CYP2C9 isoenzyme in vitro. Omeprazole does not appear to inhibit CYP3A4 activity (evaluated via erythromycin breath test). In vitro, omeprazole induces the CYP1A2 isoenzyme. Omeprazole is a substrate and inhibitor of the P-glycoprotein (P-pg) transport system.

    Oral Route

    Administration of aspirin; omeprazole with food significantly reduces the extent and absorption of omeprazole by 67% and 84%, respectively; therefore, aspirin; omeprazole should be administered at least 60 minutes before a meal. Following single dose administration of aspirin; omeprazole, peak concentrations of acetylsalicylic acid were reached at 2.5 hours for the 81 mg; 40 mg tablet and 2 to 4.5 hours for the 325 mg; 40 mg tablets. The Cmax and AUC of acetylsalicylic acid were 2.6 mcg/mL and 3 mcg/hr/mL, respectively, following administration of the 81 mg; 40 mg tablet and 2.5 mcg/mL and 2.9 mcg/hr/mL, respectively, following the 325 mg; 40 mg tablets. No significant accumulation of salicylic acid and acetylsalicylic acid was observed following 7 days of 325 mg; 40 mg tablets compared to the first day of dosing. Following administration of aspirin; omeprazole, the peak plasma concentration of omeprazole was reached at 0.5 hours on both the first day of administration and at steady state. The Cmax and AUC of omeprazole ranged from 617 to 856 ng/mL and 880 to 1384 ng/hr/mL following a single dose of 325 mg; 40 mg tablets. Dosing of 325 mg; 40 mg tablets for 7 days results in approximately 2.3-fold higher AUC and 2-fold higher Cmax of omeprazole at steady state compared to the first day of dosing.