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    Angiotensin-II Receptor Blockers/ARBs

    BOXED WARNING

    Pregnancy

    Telmisartan can cause fetal harm if administered to a pregnant woman. Once pregnancy is detected, every effort should be made to discontinue telmisartan therapy. Women of child-bearing age should be made aware of the potential risk and telmisartan should only be given after careful counseling and consideration of individual risks and benefits. When used during the second and third trimesters, drugs that affect the renin-angiotensin system (e.g., ACE inhibitors, angiotensin II receptor antagonists) reduce fetal renal function and increase fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Other potential neonatal adverse effects include skull hypoplasia, anuria, and hypotension. Retrospective data indicate that first trimester use of ACE inhibitors has been associated with a potential risk of birth defects. However, a much larger observational study (n = 465,754) found that the risk of birth defects was similar in infants exposed to ACE inhibitors during the first trimester, in infants exposed to other antihypertensives during the first trimester, and in those whose mothers were hypertensive but were not treated. Infants born to mothers with hypertension, either treated or untreated, had a higher risk of birth defects than those born to mothers without hypertension. The authors concluded that the presence of hypertension likely contributed to the development of birth defects rather than the use of medications. In rare cases when another antihypertensive agent cannot be used to treat a pregnant patient, serial ultrasound examinations should be performed to assess the intraamniotic environment. If oligohydramnios is observed, discontinue telmisartan unless it is considered life-saving for the mother. It should be noted that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe newborns with histories of in utero exposure to telmisartan for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occurs, blood pressure and renal perfusion support may be required, as well as exchange transfusion or dialysis to reverse hypotension and/or support decreased renal function.

    DEA CLASS

    Rx

    DESCRIPTION

    Angiotensin II receptor blocker (ARB)
    Used for HTN and for cardiovascular risk reduction, such as stroke and MI prophylaxis, in high-risk patients unable to take ACE inhibitors
    Does not inhibit ACE and accumulate bradykinin; less likely to cause cough or angioedema than ACE inhibitors

    COMMON BRAND NAMES

    Micardis

    HOW SUPPLIED

    Micardis/Telmisartan Oral Tab: 20mg, 40mg, 80mg

    DOSAGE & INDICATIONS

    For the treatment of hypertension, either alone or in combination with other antihypertensive agents.
    Oral dosage
    Adults, including the geriatric

    Initially, 40 mg PO once daily, unless the patient is volume-depleted. Begin therapy with 20 mg PO once daily in volume-depleted patients (e.g., patients taking diuretics). The dosage range is 20 to 80 mg PO once daily. Maximal blood pressure reduction generally occurs after 4 weeks. If blood pressure is not controlled with telmisartan alone, a diuretic (e.g., hydrochlorothiazide) may be added.

    For stroke prophylaxis, myocardial infarction prophylaxis, and reduction of cardiovascular mortality in adults 55 years of age and older who are at high risk of developing major cardiovascular events who are unable to take ACE inhibitors.
    Oral dosage
    Adults >= 55 years

    80 mg PO once daily. Upon initiation of therapy, monitor blood pressure and adjust doses of other antihypertensive medications as necessary. Patients with a history of coronary artery disease, peripheral arterial disease, stroke, transient ischemic attack, or high-risk diabetes (insulin-dependent or non-insulin dependent) with evidence of end-organ damage are considered high risk. In the ONTARGET study, telmisartan 80 mg/day was compared to ramipril 10 mg/day and the combination of the two drugs in patients with vascular disease or high-risk diabetes. Ramipril reduced stroke and MI by 32% and 20%, respectively, in high-risk patients with or without left ventricular dysfunction in the HOPE trial. In the ONTARGET study, telmisartan was found to be as effective (i.e., non-inferior) as ramipril with significantly fewer episodes of cough and edema. There was, however, a significantly greater number of hypotensive symptoms associated with telmisartan use. There was no benefit, but rather, increased harm associated with combination therapy.

    For the treatment of proteinuria† or diabetic nephropathy†.
    Oral dosage
    Adults

    Clinical trials have initiated dosage at 40 mg PO once daily for 4 to 12 weeks, followed by titration to 80 mg PO once daily in hypertensive patients with nephropathy or proteinuria associated with type 2 diabetes or chronic kidney disease. The DETAIL study reported that telmisartan is not inferior to enalapril in delaying the progression of renal dysfunction in patients with diabetic nephropathy. This study evaluated glomerular filtration rate (GFR) over 5 years in type 2 diabetics with mild to moderate hypertension and early stages of nephropathy (baseline urinary albumin excretion rate between 11 to 999 mcg/minute and baseline estimated GFR greater than 70 mL/min/1.73 m2).

    †Indicates off-label use

    MAXIMUM DOSAGE

    Adults

    80 mg/day PO.

    Elderly

    80 mg/day PO.

    Adolescents

    Safety and efficacy have not been established.

    Children

    Safety and efficacy have not been established.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    Telmisartan is primarily eliminated by biliary excretion and initial dosage reduction (20 mg PO once daily) is warranted in patients with hepatic impairment.

    Renal Impairment

    No dosage adjustment is needed.
     
    Intermittent hemodialysis:
    Telmisartan is not significantly removed by hemodialysis.

    ADMINISTRATION

    Oral Administration

    May administer without regard to food.

    STORAGE

    Micardis:
    - Protect from moisture
    - Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
    - Store in original package until time of use

    CONTRAINDICATIONS / PRECAUTIONS

    Hypotension, hypovolemia

    Telmisartan should be used with caution in patients with hypovolemia, including patients receiving high doses of diuretics. Telmisartan should be used with great care in patients who exhibit signs of hypotension. Intravascular volume and/or salt-depletion increases the risk for symptomatic hypotension, especially after administration of the first dose. Volume depletion should be corrected prior to the administration of telmisartan.

    Heart failure, renal artery stenosis

    Telmisartan should be used with caution in patients whose renal function is critically dependent on the activity of the renin-angiotensin-aldosterone system (RAS) (e.g., patients with heart failure). Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor antagonists affect the RAS system and have caused increases in serum creatinine in susceptible individuals. Although serum creatinine returns to baseline or stabilizes in most patients with continued use, oliguria, progressive azotemia, and rarely acute renal failure have occurred in this patient population. In addition, ACEIs have been associated with azotemia in patients with unilateral or bilateral renal artery stenosis. Although telmisartan has not been studied in renal artery stenosis, similar effects to the ACEIs might be anticipated due to telmisartan's pharmacology.

    Hepatic disease

    Telmisartan should be used with caution in patients with hepatic disease. Patients with hepatic impairment, including those with biliary obstruction, have significantly increased plasma telmisartan concentrations compared to patients with normal hepatic function. Thus, in patients with hepatic impairment, begin therapy at a reduced dosage (see Dosage); then adjust dosage to achieve clinical goals.

    ACE-inhibitor induced angioedema, angioedema

    Anaphylactic reactions (anaphylactoid reactions) and angioedema have been reported with angiotensin II receptor antagonists. Theoretically, angiotensin II receptor antagonists should be less likely than angiotensin converting enzyme inhibitors (ACEIs) to precipitate angioedema because angiotensin II receptor antagonists do not cause accumulation of kinins. However, angioedema (swelling of lips and eyelids, facial rash) has been rarely reported in patients receiving angiotensin II receptor antagonists, including in patients with ACE-inhibitor induced angioedema. While angiotensin II receptor antagonists have been suggested as potential alternatives to ACE inhibitors for patients who experience angioedema due to a lower frequency of associated angioedema , the safety of angiotensin II receptor antagonists in patients with a prior history of ACE-inhibitor induced angioedema has not been definitively established. It is prudent to use substantial caution when prescribing telmisartan in patients with a history of angioedema related to ACE inhibitor therapy. Some authors have recommended that angiotensin II receptor antagonists should be avoided in patients with a history of angioedema, especially in those with ACE-inhibitor induced angioedema.

    Hyperkalemia

    Telmisartan should be used with caution patients with hyperkalemia. Angiotensin II blockade can theoretically elevate serum potassium concentrations by blocking aldosterone secretion and could worsen preexisting hyperkalemia. Although infrequent, significant hyperkalemia has been reported during post-marketing experience with angiotensin II receptor antagonists. Patients should be instructed not to use potassium supplements or salt substitutes containing potassium without consulting the prescribing physician.

    Black patients

    Although telmisartan is effective in reducing blood pressure in Black patients (a low renin population), there is generally a smaller antihypertensive response compared to other ethnic populations. A greater proportion of Black patients will attain blood pressure goals when angiotensin II receptor antagonists are combined with a diuretic.

    Pregnancy

    Telmisartan can cause fetal harm if administered to a pregnant woman. Once pregnancy is detected, every effort should be made to discontinue telmisartan therapy. Women of child-bearing age should be made aware of the potential risk and telmisartan should only be given after careful counseling and consideration of individual risks and benefits. When used during the second and third trimesters, drugs that affect the renin-angiotensin system (e.g., ACE inhibitors, angiotensin II receptor antagonists) reduce fetal renal function and increase fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Other potential neonatal adverse effects include skull hypoplasia, anuria, and hypotension. Retrospective data indicate that first trimester use of ACE inhibitors has been associated with a potential risk of birth defects. However, a much larger observational study (n = 465,754) found that the risk of birth defects was similar in infants exposed to ACE inhibitors during the first trimester, in infants exposed to other antihypertensives during the first trimester, and in those whose mothers were hypertensive but were not treated. Infants born to mothers with hypertension, either treated or untreated, had a higher risk of birth defects than those born to mothers without hypertension. The authors concluded that the presence of hypertension likely contributed to the development of birth defects rather than the use of medications. In rare cases when another antihypertensive agent cannot be used to treat a pregnant patient, serial ultrasound examinations should be performed to assess the intraamniotic environment. If oligohydramnios is observed, discontinue telmisartan unless it is considered life-saving for the mother. It should be noted that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe newborns with histories of in utero exposure to telmisartan for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occurs, blood pressure and renal perfusion support may be required, as well as exchange transfusion or dialysis to reverse hypotension and/or support decreased renal function.

    Breast-feeding

    There is no information on the presence of telmisartan in human milk, the effects on the breastfed infant, or the effects on milk production. Telmisartan is present in the milk of lactating rats at 1.5 to 2 times those found in plasma from 4 to 8 hours after administration. Due to the potential for serious adverse reactions in the breastfed infant including hypotension, hypokalemia, and renal impairment, breast-feeding is not recommended during telmisartan treatment.Previous American Academy of Pediatrics recommendations consider the ACE inhibitors captopril and enalapril usually compatible with breast-feeding. In addition, benazepril and quinapril are excreted in human breast milk in very small quantities ; therefore, a clinically significant risk to a breast-feeding infant is not expected.

    Children

    The safety and effectiveness of telmisartan have not been established in children.

    Surgery

    In patients undergoing major surgery or during anesthesia with agents that lower blood pressure, telmisartan may enhance hypotensive effects via angiotensin II blockade. Therefore, telmisartan should be used with caution prior to surgery. If hypotension occurs during surgery and/or anesthesia and is considered to be due to blockade of angiotensin II formation, it can be corrected by volume expansion.

    Geriatric

    During clinical trial evaluation, there were no overall differences in efficacy or safety of telmisartan in geriatric versus younger patients. However, greater sensitivity to the hypotensive effects of telmisartan is possible in geriatric patients due to an age-related decline in renal function. The federal Omnibus Budget Reconciliation Act (OBRA) regulates medication use in residents of long-term care facilities (LTCFs). According to OBRA, antihypertensive regimens should be individualized to achieve the desired outcome while minimizing adverse effects. Antihypertensives may cause dizziness, postural hypotension, fatigue, and there is an increased risk for falls. Angiotensin receptor blockers (ARBs) may cause angioedema, chronic persistent non-productive cough, and may worsen renal failure. Some agents require a gradual taper to avoid adverse consequences caused by abrupt discontinuation. There are many drug interactions that can potentiate the effects of antihypertensives. Combination therapy of an ARB with a potassium-sparing diuretic or potassium supplementation has the potential for life-threatening elevations of serum potassium.

    ADVERSE REACTIONS

    Severe

    angioedema / Rapid / 0-1.0
    anaphylactoid reactions / Rapid / 0-1.0
    renal failure (unspecified) / Delayed / 0-1.0
    rhabdomyolysis / Delayed / 0-1.0
    myocardial infarction / Delayed / Incidence not known
    atrial fibrillation / Early / Incidence not known
    heart failure / Delayed / Incidence not known
    bradycardia / Rapid / Incidence not known
    hyperkalemia / Delayed / Incidence not known
    oliguria / Early / Incidence not known
    azotemia / Delayed / Incidence not known
    teratogenesis / Delayed / Incidence not known

    Moderate

    skin ulcer / Delayed / 3.0-3.0
    orthostatic hypotension / Delayed / 0-1.0
    hypotension / Rapid / Incidence not known
    edema / Delayed / Incidence not known
    chest pain (unspecified) / Early / Incidence not known
    erythema / Early / Incidence not known
    hyperuricemia / Delayed / Incidence not known
    hypoglycemia / Early / Incidence not known
    eosinophilia / Delayed / Incidence not known
    thrombocytopenia / Delayed / Incidence not known
    anemia / Delayed / Incidence not known
    elevated hepatic enzymes / Delayed / Incidence not known
    impotence (erectile dysfunction) / Delayed / Incidence not known

    Mild

    infection / Delayed / 7.0-7.0
    back pain / Delayed / 3.0-3.0
    diarrhea / Early / 3.0-3.0
    sinusitis / Delayed / 3.0-3.0
    cough / Delayed / 1.6-1.6
    pharyngitis / Delayed / 1.0-1.0
    dizziness / Early / 1.0
    rash / Early / 0.3
    pruritus / Rapid / 0.3
    syncope / Early / Incidence not known
    fatigue / Early / Incidence not known
    dyspepsia / Early / Incidence not known
    weakness / Early / Incidence not known
    urticaria / Rapid / Incidence not known
    diaphoresis / Early / Incidence not known
    muscle cramps / Delayed / Incidence not known
    headache / Early / Incidence not known
    abdominal pain / Early / Incidence not known
    myalgia / Early / Incidence not known
    asthenia / Delayed / Incidence not known

    DRUG INTERACTIONS

    Acarbose: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Acetaminophen; Chlorpheniramine; Phenylephrine; Phenyltoloxamine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Acetaminophen; Dichloralphenazone; Isometheptene: (Moderate) Isometheptene has sympathomimetic properties. Patients taking antihypertensive agents may need to have their therapy modified. Careful blood pressure monitoring is recommended.
    Acetaminophen; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Acrivastine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Aldesleukin, IL-2: (Moderate) Angiotensin II receptor antagonists may potentiate the hypotension seen with aldesleukin, IL 2.
    Alemtuzumab: (Moderate) Alemtuzumab may cause hypotension. Careful monitoring of blood pressure and hypotensive symptoms is recommended especially in patients with ischemic heart disease and in patients on antihypertensive agents.
    Aliskiren: (Major) Most patients receiving the combination of two renin-angiotensin-aldosterone system (RAAS) inhibitors, such as angiotensin II receptor antagonists (ARBs) and aliskiren do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAAS inhibitors particularly in patients with CrCl < 60 mL/min. Closely monitor blood pressure, renal function, and electrolytes if aliskiren is combined with another RAAS inhibitor. Aliskiren-containing products are contraindicated in combination with ARBs in patients with diabetes mellitus. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Aliskiren; Amlodipine: (Major) Most patients receiving the combination of two renin-angiotensin-aldosterone system (RAAS) inhibitors, such as angiotensin II receptor antagonists (ARBs) and aliskiren do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAAS inhibitors particularly in patients with CrCl < 60 mL/min. Closely monitor blood pressure, renal function, and electrolytes if aliskiren is combined with another RAAS inhibitor. Aliskiren-containing products are contraindicated in combination with ARBs in patients with diabetes mellitus. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ: (Major) Most patients receiving the combination of two renin-angiotensin-aldosterone system (RAAS) inhibitors, such as angiotensin II receptor antagonists (ARBs) and aliskiren do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAAS inhibitors particularly in patients with CrCl < 60 mL/min. Closely monitor blood pressure, renal function, and electrolytes if aliskiren is combined with another RAAS inhibitor. Aliskiren-containing products are contraindicated in combination with ARBs in patients with diabetes mellitus. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Aliskiren; Hydrochlorothiazide, HCTZ: (Major) Most patients receiving the combination of two renin-angiotensin-aldosterone system (RAAS) inhibitors, such as angiotensin II receptor antagonists (ARBs) and aliskiren do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAAS inhibitors particularly in patients with CrCl < 60 mL/min. Closely monitor blood pressure, renal function, and electrolytes if aliskiren is combined with another RAAS inhibitor. Aliskiren-containing products are contraindicated in combination with ARBs in patients with diabetes mellitus. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Aliskiren; Valsartan: (Major) Most patients receiving the combination of two renin-angiotensin-aldosterone system (RAAS) inhibitors, such as angiotensin II receptor antagonists (ARBs) and aliskiren do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAAS inhibitors particularly in patients with CrCl < 60 mL/min. Closely monitor blood pressure, renal function, and electrolytes if aliskiren is combined with another RAAS inhibitor. Aliskiren-containing products are contraindicated in combination with ARBs in patients with diabetes mellitus. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Alkalinizing Agents: (Major) Products containing a potassium salt, including citric acid; potassium citrate; sodium citrate, should be used with caution in patients taking drugs that may increase serum potassium concentrations, such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Alogliptin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Alpha-glucosidase Inhibitors: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Alprostadil: (Minor) The concomitant use of systemic alprostadil injection and antihypertensive agents, such as angiotensin II receptor antagonists (angiotensin receptor blockers, or ARBs), may cause additive hypotension. Caution is advised with this combination. Systemic drug interactions with the urethral suppository (MUSE) or alprostadil intracavernous injection are unlikely in most patients because low or undetectable amounts of the drug are found in the peripheral venous circulation following administration. In those men with significant corpora cavernosa venous leakage, hypotension might be more likely. Use caution with in-clinic dosing for erectile dysfunction (ED) and monitor for the effects on blood pressure. However, in clinical trials with alprostadil intracavernous injection, anti-hypertensive agents had no apparent effect on the safety and efficacy of alprostadil.
    Amifostine: (Major) Patients receiving angiotensin II receptor antagonists should be closely monitored during amifostine infusions due to additive effects. Patients receiving amifostine at doses recommended for chemotherapy should have antihypertensive therapy interrupted 24 hours preceding administration of amifostine. If the antihypertensive cannot be stopped, patients should not receive amifostine.
    Amiloride: (Major) Potassium-sparing diuretics, such as amiloride, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Amiloride; Hydrochlorothiazide, HCTZ: (Major) Potassium-sparing diuretics, such as amiloride, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Amobarbital: (Moderate) Concurrent use of amobarbital with antihypertensive agents may lead to hypotension. Monitor for decreases in blood pressure during times of coadministration.
    Amphetamine; Dextroamphetamine Salts: (Major) Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, such as angiotensin II receptor antagonists. Close monitoring of blood pressure or the selection of alternative therapeutic agents may be needed.
    Amyl Nitrite: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Angiotensin II: (Moderate) Angiotensin II receptor antagonists may decrease the response to angiotensin II.
    Angiotensin-converting enzyme inhibitors: (Major) Most patients receiving the combination of two renin-angiotensin-aldosterone system (RAAS) inhibitors, such as angiotensin-converting enzyme inhibitors (ACE inhibitors) and angiotensin II receptor antagonists (ARBs) do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of these drugs together. Closely monitor blood pressure, renal function, and electrolytes. Combination therapy has been associated with an increased risk of diarrhea, hypotension, syncope, hyperkalemia, and renal dysfunction resulting in dialysis, doubling of serum creatinine, and death. In the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET), the combination of ramipril 10 mg/day and telmisartan 80 mg/day did not provide a significant benefit in the prevention of death from cardiovascular causes, myocardial infarction, stroke, or hospitalization for heart failure compared to ramipril alone. There was, however, a significantly increased rate of renal dysfunction associated with combination therapy (13.5%) compared to ramipril (10.2%) or telmisartan (10.6%) alone and a significantly increased rate of hyperkalemia with combination therapy compared to ramipril (5.6% vs. 3.3%; p<0.001). Additionally, there was a significantly higher number of patients who discontinued therapy due to adverse reactions, including hypotensive symptoms (4.8% vs. 1.7%; p<0.001), syncope (0.3% vs. 0.2%; p=0.03), diarrhea (0.5% vs. 0.1%; p<0.001), and renal impairment (1.1% vs. 0.7%; p<0.001), from combination therapy compared to ramipril alone. In a separate analysis of the ONTARGET renal outcomes, the rate of the composite primary renal outcome of dialysis, doubling of serum creatinine, and death was similar with ramipril and telmisartan alone (13.5% vs. 13.6%, respectively), but was significantly higher with combination therapy (14.5%) compared to ramipril (p=0.037). In the CHARM-Added program, the combination of candesartan and an ACE-inhibitor resulted in an increased incidence of hypotension (22.6% vs. 13.8%), renal dysfunction (15% vs. 9%), and hyperkalemia (9.5% vs. 3.5%) compared to placebo combined with an ACE inhibitor. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury. Patients receiving concomitant therapy with ACE inhibitors and ARBs should be closely monitored for renal dysfunction, hypotension, and hyperkalemia.
    Apomorphine: (Moderate) Patients receiving apomorphine may experience orthostatic hypotension, hypotension, and/or syncope. Extreme caution should be exercised if apomorphine is used concurrently with antihypertensive agents, or vasodilators such as nitrates.
    Apraclonidine: (Minor) Alpha blockers as a class may reduce heart rate and blood pressure. While no specific drug interactions have been identified with systemic agents and apraclonidine during clinical trials, it is theoretically possible that additive blood pressure reductions could occur when apraclonidine is combined with the use of antihypertensive agents. Patients using cardiovascular drugs concomitantly with apraclonidine should have their pulse and blood pressure monitored periodically.
    Aripiprazole: (Minor) Aripiprazole may enhance the hypotensive effects of antihypertensive agents.
    Asenapine: (Moderate) Secondary to alpha-blockade, asenapine can produce vasodilation that may result in additive effects during concurrent use of antihypertensive agents. The potential reduction in blood pressure can precipitate orthostatic hypotension and associated dizziness, tachycardia, and syncope. If concurrent use of asenapine and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
    Baclofen: (Moderate) Baclofen has been associated with hypotension. Concurrent use with baclofen and antihypertensive agents may result in additive hypotension. Dosage adjustments of the antihypertensive medication may be required.
    Benzphetamine: (Moderate) Benzphetamine can increase both systolic and diastolic blood pressure and may counteract the activity of angiotensin II receptor antagonists. This represents a pharmacodynamic, and not a pharmacokinetic, interaction. Close monitoring of blood pressure, especially in patients who are taking antihypertensive agents, may be needed.
    Bosentan: (Moderate) Although no specific interactions have been documented, bosentan has vasodilatory effects and may contribute additive hypotensive effects when given with angiotensin II receptor antagonists. Losartan has no effect on plasma concentrations of bosentan. However, bosentan may theoretically induce the metabolism of losartan via CYP2C9 isoenzymes (clinical significance unknown).
    Brexpiprazole: (Moderate) Due to brexpiprazole's antagonism at alpha 1-adrenergic receptors, the drug may enhance the hypotensive effects of alpha-blockers and other antihypertensive agents.
    Brompheniramine; Carbetapentane; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Brompheniramine; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Brompheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Cabergoline: (Minor) Cabergoline has minimal affinity for adrenergic receptors; however, it has been associated with hypotension in some instances. Cabergoline should be used cautiously in those receiving antihypertensive agents.
    Calcium Phosphate, Supersaturated: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as angiotensin II receptor antagonists, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Canagliflozin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Carbetapentane; Chlorpheniramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Diphenhydramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Phenylephrine; Pyrilamine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Carbidopa; Levodopa: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
    Carbidopa; Levodopa; Entacapone: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
    Carbinoxamine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Carbinoxamine; Hydrocodone; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbinoxamine; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Carbinoxamine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbinoxamine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Cariprazine: (Moderate) Orthostatic vital signs should be monitored in patients who are at risk for hypotension, such as those receiving cariprazine in combination with antihypertensive agents. Atypical antipsychotics may cause orthostatic hypotension and syncope, most commonly during treatment initiation and dosage increases. Patients should be informed about measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning, or rising slowly from a seated position. Consider a cariprazine dose reduction if hypotension occurs.
    Cetirizine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlophedianol; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chloroprocaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents.
    Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chlorpheniramine; Dihydrocodeine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlorpheniramine; Guaifenesin; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlorpheniramine; Hydrocodone; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chlorpheniramine; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlorpheniramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chlorpheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Citalopram: (Minor) The plasma concentration of citalopram, a CYP2C19 substrate, may be increased when administered concurrently with telmisartan, a weak 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.
    Clopidogrel: (Major) Telmisartan may reduce the antiplatelet activity of clopidogrel by inhibiting clopidogrel's metabolism to its active metabolite. Use clopidogrel and telmisartan together with caution and monitor for reduced efficacy of clopidogrel. Clopidogrel requires hepatic biotransformation via 2 cytochrome dependent oxidative steps; the CYP2C19 isoenzyme is involved in both steps. Telmisartan is an inhibitor of CYP2C19.
    Clozapine: (Moderate) Clozapine used concomitantly with the antihypertensive agents can increase the risk and severity of hypotension by potentiating the effect of the antihypertensive drug.
    Cocaine: (Major) Use of cocaine with antihypertensive agents may increase the antihypertensive effects of the antihypertensive medications or may potentiate cocaine-induced sympathetic stimulation.
    Cod Liver Oil: (Moderate) Fish oil supplements may cause mild, dose-dependent reductions in systolic or diastolic blood pressure in untreated hypertensive patients. Relatively high doses of fish oil are required to produce any blood pressure lowering effect. Additive reductions in blood pressure may be seen when fish oils are used in a patient already taking antihypertensive agents. (Moderate) High doses of fish oil supplements may produce a blood pressure lowering effect. It is possible that additive reductions in blood pressure may be seen when fish oils are used in a patient already taking antihypertensive agents.
    Codeine; Phenylephrine; Promethazine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Co-Enzyme Q10, Ubiquinone: (Moderate) Co-enzyme Q10, ubiquinone (CoQ10) may lower blood pressure. CoQ10 use in combination with antihypertensive agents may lead to additional reductions in blood pressure in some individuals. Patients who choose to take CoQ10 concurrently with antihypertensive medications should receive periodic blood pressure monitoring. Patients should be advised to inform their prescriber of their use of CoQ10.
    Conivaptan: (Moderate) There is potential for additive hypotensive effects when conivaptan is coadministered with antihypertensive agents.
    Cyclosporine: (Moderate) Coadministration of cyclosporine and an angiotensin II receptor antagonist, like telmisartan, may increase the risk of hyperkalemia and reduced renal function. In response to cyclosporine-induced renal afferent vasoconstriction and glomerular hypoperfusion, angiotensin II is required to maintain an adequate glomerular filtration rate. Inhibition of angiotensin-converting enzyme (ACE) could reduce renal function acutely. Several cases of acute renal failure have been associated with the addition of enalapril to cyclosporine therapy in renal transplant patients. Also, cyclosporine can cause hyperkalemia, and inhibition of angiotensin II leads to reduced aldosterone concentrations, which can increase the serum potassium concentration. Closely monitor renal function and serum potassium concentrations in patients receiving cyclosporine concurrently with telmisartan.
    Dapagliflozin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Desloratadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Dexmethylphenidate: (Moderate) Dexmethylphenidate can reduce the hypotensive effect of antihypertensive agents, including angiotensin II receptor antagonists. Periodic evaluation of blood pressure is advisable during concurrent use of dexmethylphenidate and antihypertensive agents, particularly during initial coadministration and after dosage increases of dexmethylphenidate.
    Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Dextromethorphan; Quinidine: (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
    Diazoxide: (Moderate) Additive hypotensive effects can occur with the concomitant administration of diazoxide with other antihypertensive agents. This interaction can be therapeutically advantageous, but dosages must be adjusted accordingly. The manufacturer advises that IV diazoxide should not be administered to patients within 6 hours of receiving beta-blockers, hydralazine, methyldopa, minoxidil, nitrites, prazosin, reserpine, or other antihypertensive agents.
    Diethylpropion: (Moderate) Diethylpropion has vasopressor effects and may limit the benefit of angiotensin II receptor antagonists. Although leading drug interaction texts differ in the potential for an interaction between diethylpropion and this group of antihypertensive agents, these effects are likely to be clinically significant and have been described in hypertensive patients on these medications.
    Digoxin: (Major) When telmisartan is coadministered with digoxin, median increases in digoxin peak concentration (49%) and in trough concentration (20%) are observed. Measure serum digoxin concentrations before initiating telmisartan. Reduce digoxin concentrations by decreasing the digoxin dose by approximately 15-30% or by modifying the dosing frequency and continue monitoring. In addition, caution should be exercised when administering digoxin with drugs that may cause a significant deterioration in renal function including angiotensin II receptor antagonists. A decline in glomerular filtration or tubular secretion may impair the excretion of digoxin. Close monitoring of serum digoxin concentrations is essential to avoid enhanced toxicity.
    Dihydrocodeine; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Diphenhydramine; Hydrocodone; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Diphenhydramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Drospirenone; Estradiol: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
    Drospirenone; Ethinyl Estradiol: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
    Drospirenone; Ethinyl Estradiol; Levomefolate: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
    Duloxetine: (Moderate) Orthostatic hypotension and syncope have been reported during duloxetine administration. The concurrent administration of antihypertensive agents and duloxetine may increase the risk of hypotension. Monitor blood pressure if the combination is necessary.
    Empagliflozin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Enflurane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Ephedrine: (Moderate) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved.
    Eplerenone: (Major) Monitor serum potassium and serum creatinine concentrations within 3 to 7 days of initiating coadministration of eplerenone and angiotensin II receptor antagonists (ARBs). Hyperkalemia risk is increased when eplerenone is used with ARBs. Patients who develop hyperkalemia may continue eplerenone with proper dose adjustment; eplerenone dose reduction decreases potassium concentrations.
    Epoprostenol: (Moderate) Angiotensin II receptor antagonists can enhance the hypotensive effects of antihypertensive agents if given concomitantly. This additive effect may be desirable, but dosages must be adjusted accordingly.
    Ertugliflozin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Estradiol Cypionate; Medroxyprogesterone: (Minor) Estrogens can induce fluid retention and may increase blood pressure in some patients; patients who are receiving antihypertensive agents concurrently with hormonal contraceptives should be monitored for antihypertensive effectiveness.
    Estradiol: (Minor) Estrogens can induce fluid retention and may increase blood pressure in some patients; patients who are receiving antihypertensive agents concurrently with hormonal contraceptives should be monitored for antihypertensive effectiveness.
    Etomidate: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Fexofenadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Fish Oil, Omega-3 Fatty Acids (Dietary Supplements): (Moderate) Co-enzyme Q10, ubiquinone (CoQ10) may lower blood pressure. CoQ10 use in combination with antihypertensive agents may lead to additional reductions in blood pressure in some individuals. Patients who choose to take CoQ10 concurrently with antihypertensive medications should receive periodic blood pressure monitoring. Patients should be advised to inform their prescriber of their use of CoQ10. (Moderate) High doses of fish oil supplements may produce a blood pressure lowering effect. It is possible that additive reductions in blood pressure may be seen when fish oils are used in a patient already taking antihypertensive agents.
    Fluoxetine; Olanzapine: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
    Fospropofol: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    General anesthetics: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Glipizide; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Glyburide; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Guaifenesin; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Haloperidol: (Moderate) In general, antipsychotics like haloperidol should be used cautiously with antihypertensive agents due to the possibility of additive hypotension.
    Halothane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Hawthorn, Crataegus laevigata: (Moderate) Hawthorn, Crataegus laevigata may lower peripheral vascular resistance. Hawthorn use in combination with antihypertensive agents like the angiotensin II receptor antagonists may lead to additional reductions in blood pressure in some individuals. Patients receiving hawthorn concurrently with antihypertensive medications should receive periodic blood pressure monitoring.
    Hydralazine; Isosorbide Dinitrate, ISDN: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Hydrochlorothiazide, HCTZ; Spironolactone: (Major) Potassium-sparing diuretics, such as spironolactone, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Hydrochlorothiazide, HCTZ; Triamterene: (Major) Potassium-sparing diuretics, such as triamterene, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Hydrocodone; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Hydrocodone; Potassium Guaiacolsulfonate; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Ibuprofen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Iloperidone: (Moderate) Secondary to alpha-blockade, iloperidone can produce vasodilation that may result in additive effects during concurrent use with antihypertensive agents. The potential reduction in blood pressure can precipitate orthostatic hypotension and associated dizziness, tachycardia, and syncope. If concurrent use of iloperidone and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
    Iloprost: (Moderate) Angiotensin II receptor antagonists can enhance the hypotensive effects of antihypertensive agents if given concomitantly. This additive effect may be desirable, but dosages must be adjusted accordingly.
    Incretin Mimetics: (Moderate) Angiotensin II receptor antagonists may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving these drugs concomitantly should be monitored for changes in glycemic control.
    Indapamide: (Moderate) The effects of indapamide may be additive when administered with other antihypertensive agents or diuretics. In some patients, this may be desirable, but orthostatic hypotension may occur. Angiotensin II receptor antagonists tend to reverse the potassium loss, but not the serum uric acid rise associated with thiazide diuretic monotherapy.
    Insulins: (Moderate) Monitor patients receiving angiotensin II receptor antagonists concomitantly with insulin for changes in glycemic control. Angiotensin II receptor antagonists may enhance the hypoglycemic effects of insulin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease.
    Intravenous Lipid Emulsions: (Moderate) High doses of fish oil supplements may produce a blood pressure lowering effect. It is possible that additive reductions in blood pressure may be seen when fish oils are used in a patient already taking antihypertensive agents.
    Isocarboxazid: (Moderate) Additive hypotensive effects may be seen when isocarboxazid is combined with angiotensin II receptor antagonists. Careful monitoring of blood pressure is suggested during concurrent therapy of isocarboxazid with angiotensin II receptor antagonists. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider during concurrent use of isocarboxazid and an angiotensin II receptor antagonist.
    Isoflurane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Isoproterenol: (Moderate) The pharmacologic effects of isoproterenol may cause an increase in blood pressure. If isoproterenol is used concomitantly with antihypertensives, the blood pressure should be monitored as the administration of isoproterenol can compromise the effectiveness of antihypertensive agents.
    Isosorbide Dinitrate, ISDN: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Isosorbide Mononitrate: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Ketamine: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Levodopa: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
    Levomilnacipran: (Moderate) Levomilnacipran has been associated with an increase in blood pressure. The effectiveness of angiotensin II receptor antagonists may be diminished during concurrent use of levomilnacipran. It is advisable to monitor blood pressure if the combination is necessary.
    Linagliptin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Lisdexamfetamine: (Major) Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents. Close monitoring of blood pressure or the selection of alternative therapeutic agents may be needed.
    Lithium: (Major) Angiotensin II receptor antagonists (ARBs) should be used very cautiously, if at all, in patients already receiving lithium. The risk of lithium toxicity is increased in patients receiving medications that may affect kidney function, such ARBs. These drugs decrease lithium clearance, possibly as a result of sodium depletion which leads to increased renal tubular reabsorption of lithium. If combination therapy cannot be avoided, begin with lower doses of lithium and be alert for evidence of lithium toxicity (e.g., nausea, vomiting, anorexia, drowsiness, dysarthria, tremor, confusion, lethargy, ECG changes, etc.). Consider reducing the lithium dosage in previously established patients and monitor lithium concentrations and patient response and tolerability. Conversely, clinicians should be alert to the possibility of loss of lithium effectiveness if ARBs are discontinued in a patient stabilized on lithium. According to the Beers Criteria, concurrent use of lithium and ACE inhibitors may result in a clinically important drug interaction particularly in older adults; the panel recommends avoiding concurrent use due to an increased risk of lithium toxicity. If the combination is medically necessary, monitoring of lithium concentrations is recommended.
    Loop diuretics: (Moderate) Coadministration of furosemide and Angiotensin-converting enzyme inhibitors (ACE inhibitors) or angiotensin II receptor antagonists may result in severe hypotension and deterioration in renal function, including renal failure. Hyponatremia or hypovolemia predisposes patients to acute hypotensive episodes following initiation of ACE inhibitor therapy. While ACE inhibitors and loop diuretics are routinely administered together in the treatment of heart failure, if an ACE inhibitor is to be administered to a patient receiving furosemide, initial doses should be conservative.
    Loratadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Lovastatin; Niacin: (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise.
    Lurasidone: (Moderate) Due to the antagonism of lurasidone at alpha-1 adrenergic receptors, the drug may enhance the hypotensive effects of alpha-blockers and other antihypertensive agents. If concurrent use of lurasidone and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
    Magnesium Sulfate; Potassium Sulfate; Sodium Sulfate: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists.
    Meglitinides: (Moderate) Angiotensin II receptor antagonists (ARB) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Mestranol; Norethindrone: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients; monitor patients receiving concurrent therapy to confirm that the desired antihypertensive effect is being obtained.
    Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Pioglitazone: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Repaglinide: (Moderate) Angiotensin II receptor antagonists (ARB) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control. (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Rosiglitazone: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Saxagliptin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Sitagliptin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Methamphetamine: (Major) Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, such as angiotensin II receptor antagonists. Close monitoring of blood pressure or the selection of alternative therapeutic agents may be needed.
    Methohexital: (Moderate) Concurrent use of methohexital and antihypertensive agents increases the risk of developing hypotension.
    Methylphenidate: (Moderate) Methylphenidate can reduce the hypotensive effect of antihypertensive agents such as angiotensin II receptor antagonists. Periodic evaluation of blood pressure is advisable during concurrent use of methylphenidate and antihypertensive agents, particularly during initial coadministration and after dosage increases of methylphenidate.
    Miglitol: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Milnacipran: (Moderate) Milnacipran has been associated with an increase in blood pressure. The effectiveness of antihypertensive agents may be diminished during concurrent use of milnacipran. It is advisable to monitor blood pressure if the combination is necessary.
    Milrinone: (Moderate) Concurrent administration of antihypertensive agents could lead to additive hypotension when administered with milrinone. Titrate milrinone dosage according to hemodynamic response.
    Mycophenolate: (Moderate) Concommitant administration of telmisartan and mycophenolate resulted in a 30% decrease in mycophenolic acid (MPA) concentration. Telmisartan enhances PPAR gamma (peroxisome proliferator-activated receptor gamma) expression, which results in enhanced UGT1A9 expression and activity. MPA is primarily metabolized by glucuronyl transferase to the phenolic glucuronide of MPA (MPAG) which is not pharmacologically active. Monitor patients receiving these drugs concurrently for signs or symptoms of organ rejection.
    Naproxen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Nateglinide: (Moderate) Angiotensin II receptor antagonists (ARB) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Nefazodone: (Minor) Although relatively infrequent, nefazodone may cause orthostatic hypotension in some patients; this effect may be additive with antihypertensive agents. Blood pressure monitoring is recommended. Dependent upon clinical response, dosage adjustments of either drug may be necessary.
    Nesiritide, BNP: (Major) The potential for hypotension may be increased when coadministering nesiritide with antihypertensive agents.
    Niacin, Niacinamide: (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise.
    Niacin; Simvastatin: (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise.
    Nitrates: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Nitroglycerin: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Nitroprusside: (Moderate) Additive hypotensive effects may occur when nitroprusside is used concomitantly with other antihypertensive agents. Dosages should be adjusted carefully, according to blood pressure.
    Nonsteroidal antiinflammatory drugs: (Moderate) Nonsteroidal antiinflammatory drugs (NSAIDs) (including selective COX-2 inhibitors) may alter the response to Angiotensin II receptor blockers due to inhibition of vasodilatory prostaglandins. Among NSAIDs, indomethacin, naproxen, and piroxicam may have the greatest pressor effect, while the effects of sulindac and nabumetone may be significantly less. In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function who are being treated with NSAIDs, coadministration of angiotensin II receptor antagonists may result in further deterioration of renal function, including acute renal failure. These effects are usually reversible.
    Olanzapine: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
    Oxymetazoline: (Major) The vasoconstricting actions of oxymetazoline, an alpha adrenergic agonist, may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. If these drugs are used together, closely monitor for changes in blood pressure.
    Paliperidone: (Moderate) Paliperidone may cause orthostatic hypotension, thereby enhancing the hypotensive effects of antihypertensive agents. Orthostatic vital signs should be monitored in patients receiving paliperidone and angiotensin II receptor antagonists who are susceptible to hypotension.
    Pentoxifylline: (Moderate) Pentoxifylline has been used concurrently with antihypertensive drugs (beta blockers, diuretics) without observed problems. Small decreases in blood pressure have been observed in some patients treated with pentoxifylline; periodic systemic blood pressure monitoring is recommended for patients receiving concomitant antihypertensives. If indicated, dosage of the antihypertensive agents should be reduced.
    Phenelzine: (Moderate) Additive hypotensive effects may be seen when phenelzine is combined with angiotensin II receptor antagonists. Careful monitoring of blood pressure is suggested during concurrent therapy of phenelzine with angiotensin II receptor antagonists. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider during concurrent use of phenelzine and angiotensin II receptor antagonists.
    Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Phenylephrine; Promethazine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Polyethylene Glycol; Electrolytes: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists.
    Polyethylene Glycol; Electrolytes; Ascorbic Acid: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists.
    Potassium: (Major) Potassium salts should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients. Also, use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists.
    Pramlintide: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of pramlintide by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with pramlintide should be monitored for changes in glycemic control.
    Prazosin: (Moderate) razosin is well-known to produce a 'first-dose' phenomenon. Some patients develop significant hypotension shortly after administration of the first dose. The first dose response (acute postural hypotension) of prazosin may be exaggerated in patients who are receiving beta-adrenergic blockers, diuretics, or other antihypertensive agents. Concomitant administration of prazosin with other antihypertensive agents is not prohibited, however. This can be therapeutically advantageous, but lower dosages of each agent should be used.
    Procainamide: (Moderate) Procainamide can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents. Intravenous administration of procainamide is more likely to cause hypotensive effects.
    Procaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents.
    Propofol: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Quinidine: (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
    Rasagiline: (Moderate) Additive hypotensive effects may be seen when rasagiline is combined with angiotensin II receptor antagonists. Careful monitoring of blood pressure is suggested during coadministration. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider.
    Repaglinide: (Moderate) Angiotensin II receptor antagonists (ARB) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Risperidone: (Moderate) Risperidone may induce orthostatic hypotension and thus enhance the hypotensive effects of angiotensin II receptor antagonists. Lower initial doses or slower dose titration of risperidone may be necessary in patients receiving angiotensin II receptor antagonists concomitantly.
    Selegiline: (Moderate) Additive hypotensive effects may be seen when selegiline is combined with angiotensin II receptor antagonists. Careful monitoring of blood pressure is suggested during coadministration. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider.
    Sevoflurane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    SGLT2 Inhibitors: (Moderate) Patients receiving these drugs concomitantly should be monitored for changes in blood pressure, volume status, renal function, serum potassium and other electrolytes, and for glycemic control. When an SGLT2 inhibitor is initiated, mild diuresis and naturesis occurs, producing intravascular volume contraction. These effects may be additive to certain antihypertensive medications, such as the angiotensin II receptor antagonists (also known as angiotensin receptor blockers or ARBs). Patients with impaired renal function (eGFR less than 60 mL/minute/1.73 m2), low systolic blood pressure, or who are elderly may also be at a greater risk. Volume status should be assessed and corrected. In addition, some SGLT2 inhibitors, like canagliflozin, can increase serum potassium. Monitor serum potassium levels periodically and monitor for hyperkalemia. ARBs may also enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity.
    Silodosin: (Moderate) During clinical trials with silodosin, the incidence of dizziness and orthostatic hypotension was higher in patients receiving concomitant antihypertensive treatment. Thus, caution is advisable when silodosin is administered with antihypertensive agents.
    Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as angiotensin II receptor antagonists, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Moderate) Use caution when prescribing sodium picosulfate; magnesium oxide; anhydrous citric acid in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists. In addition, use caution in patients receiving drugs where hypokalemia is a particular risk.
    Spironolactone: (Major) Potassium-sparing diuretics, such as spironolactone, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Moderate) Monitor for hyperkalemia if concomitant use of an angiotensin II receptor antagonist and trimethoprim is necessary. Hyperkalemia may be more significant in patients receiving IV trimethoprim. For those patients at higher risk of hyperkalemia (e.g., the elderly, patients with underlying disorders of potassium metabolism, and those with renal dysfunction), consideration of an alternate antibiotic may be warranted. Trimethoprim has a potassium-sparing effect on the distal nephron and may induce hyperkalemia, especially in those with pre-existing risk factors.
    Sulfonylureas: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Terbinafine: (Moderate) Due to the risk for terbinafine related adverse effects, caution is advised when coadministering telmisartan. Although this interaction has not been studied by the manufacturer, and published literature suggests the potential for interactions to be low, taking these drugs together may increase the systemic exposure of terbinafine. Predictions about the interaction can be made based on the metabolic pathways of both drugs. Terbinafine is metabolized by at least 7 CYP isoenyzmes, with major contributions coming from CYP2C19; telmisartan is an inhibitor of this enzyme. Monitor patients for adverse reactions if these drugs are coadministered.
    Tetracaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents. Use extreme caution with the concomitant use of tetracaine and antihypertensive agents.
    Thiazolidinediones: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Thiopental: (Moderate) Concurrent use of thiopental and alpha-blockers or antihypertensive agents increases the risk of developing hypotension.
    Thiothixene: (Moderate) Thiothixene should be used cautiously in patients receiving antihypertensive agents. Additive hypotensive effects are possible.
    Tizanidine: (Moderate) Concurrent use of tizanidine with antihypertensive agents can result in significant hypotension. Caution is advised when tizanidine is to be used in patients receiving concurrent antihypertensive therapy.
    Tolvaptan: (Moderate) Monitor serum potassium concentrations after initiation of tolvaptan therapy in patients receiving angiotensin II receptor antagonists. Tolvaptan therapy results in an acute reduction in extracellular fluid volume which may result in increased serum potassium. In clinical studies, hyperkalemia was reported at a rate 1% to 2% higher when tolvaptan was administered with angiotensin II receptor blockers than when angiotensin II receptor blockers were administered with placebo.
    Tranylcypromine: (Severe) The use of hypotensive agents and tranylcypromine is contraindicated by the manufacturer of tranylcypromine because the effects of hypotensive agents may be markedly potentiated.
    Trazodone: (Minor) Due to additive hypotensive effects, patients receiving antihypertensive agents concurrently with trazodone may have excessive hypotension. Decreased dosage of the antihypertensive agent may be required when given with trazodone.
    Triamterene: (Major) Potassium-sparing diuretics, such as triamterene, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Trimethoprim: (Moderate) Monitor for hyperkalemia if concomitant use of an angiotensin II receptor antagonist and trimethoprim is necessary. Hyperkalemia may be more significant in patients receiving IV trimethoprim. For those patients at higher risk of hyperkalemia (e.g., the elderly, patients with underlying disorders of potassium metabolism, and those with renal dysfunction), consideration of an alternate antibiotic may be warranted. Trimethoprim has a potassium-sparing effect on the distal nephron and may induce hyperkalemia, especially in those with pre-existing risk factors.
    Warfarin: (Minor) The coadministration of telmisartan and warfarin may lead to a decrease in the anticoagulation effects of warfarin.
    Yohimbine: (Moderate) Yohimbine can increase blood pressure and therefore can antagonize the therapeutic action of antihypertensive agents. Use with particular caution in hypertensive patients with high or uncontrolled blood pressure.
    Ziprasidone: (Minor) Ziprasidone is a moderate antagonist of alpha-1 receptors and may cause orthostatic hypotension with or without tachycardia, dizziness, or syncope. Additive hypotensive effects are possible if ziprasidone is used concurrently with antihypertensive agents.

    PREGNANCY AND LACTATION

    Pregnancy

    Telmisartan can cause fetal harm if administered to a pregnant woman. Once pregnancy is detected, every effort should be made to discontinue telmisartan therapy. Women of child-bearing age should be made aware of the potential risk and telmisartan should only be given after careful counseling and consideration of individual risks and benefits. When used during the second and third trimesters, drugs that affect the renin-angiotensin system (e.g., ACE inhibitors, angiotensin II receptor antagonists) reduce fetal renal function and increase fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Other potential neonatal adverse effects include skull hypoplasia, anuria, and hypotension. Retrospective data indicate that first trimester use of ACE inhibitors has been associated with a potential risk of birth defects. However, a much larger observational study (n = 465,754) found that the risk of birth defects was similar in infants exposed to ACE inhibitors during the first trimester, in infants exposed to other antihypertensives during the first trimester, and in those whose mothers were hypertensive but were not treated. Infants born to mothers with hypertension, either treated or untreated, had a higher risk of birth defects than those born to mothers without hypertension. The authors concluded that the presence of hypertension likely contributed to the development of birth defects rather than the use of medications. In rare cases when another antihypertensive agent cannot be used to treat a pregnant patient, serial ultrasound examinations should be performed to assess the intraamniotic environment. If oligohydramnios is observed, discontinue telmisartan unless it is considered life-saving for the mother. It should be noted that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe newborns with histories of in utero exposure to telmisartan for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occurs, blood pressure and renal perfusion support may be required, as well as exchange transfusion or dialysis to reverse hypotension and/or support decreased renal function.

    There is no information on the presence of telmisartan in human milk, the effects on the breastfed infant, or the effects on milk production. Telmisartan is present in the milk of lactating rats at 1.5 to 2 times those found in plasma from 4 to 8 hours after administration. Due to the potential for serious adverse reactions in the breastfed infant including hypotension, hypokalemia, and renal impairment, breast-feeding is not recommended during telmisartan treatment.Previous American Academy of Pediatrics recommendations consider the ACE inhibitors captopril and enalapril usually compatible with breast-feeding. In addition, benazepril and quinapril are excreted in human breast milk in very small quantities ; therefore, a clinically significant risk to a breast-feeding infant is not expected.

    MECHANISM OF ACTION

    Mechanism of Action: Telmisartan antagonizes angiotensin II (AG II) at the AT1 receptor subtype. Two angiotensin II receptors, AT1 and AT2, have been identified. While telmisartan has about a 3,000-fold greater affinity for the AT1 subtype than the AT2 subtype, the AT2 subtype is not known to mediate cardiovascular homeostasis. Angiotensin II is the primary vasoactive hormone of the renin-angiotensin system and plays an important role in the pathophysiology of hypertension and congestive heart failure. Besides being a potent vasoconstrictor, the effects of angiotensin II include stimulation of the synthesis and release of aldosterone, cardiac stimulation, and renal reabsorption of sodium. By blocking the effects of angiotensin II, telmisartan decreases systemic vascular resistance without a marked change in heart rate. Circulating levels of both renin and angiotensin II rise in response to blockade of AT1 receptors; however, the increases in renin and AG II do not overcome the effect of temisartan on blood pressure. Plasma aldosterone concentrations remain unchanged following administration of up to 80 mg of telmisartan. Because telmisartan does not inhibit ACE (kininase II), it also does not inhibit the breakdown of bradykinin. Telmisartan does not bind to or block other hormone receptors or ion channels known to be important in cardiovascular regulation. Administration of telmisartan to hypertensive patients with normal renal function has not been shown to cause clinically significant changes in electrolytes (serum potassium or sodium) or in metabolic function (e.g., serum levels of cholesterol, triglycerides, glucose, or uric acid). Telmisartan does not appear to affect renal blood flow, glomerular filtration rate, renovascular resistance, or creatinine clearance when administered to hypertensive patients.

    PHARMACOKINETICS

    Telmisartan is administered orally. It is highly bound to plasma proteins (> 99.5%), mainly albumin and alpha1-acid glycoprotein. The volume of distribution is about 500 liters, indicating additional tissue binding. Telmisartan is metabolized by conjugation to form an inactive acylglucuronide. After a single dose, the glucuronide represents approximately 11% of the measured radioactivity in plasma. The cytochrome P450 enzymes are not involved in metabolism. Following oral administration of radiolabelled telmisartan, most of the administered dose (> 97%) is eliminated unchanged in feces via biliary excretion; only minute amounts are found in the urine. The elimination half-life is about 24 hours.
     
    In normal volunteers, a dose of telmisartan 80 mg inhibited the pressor response to an intravenous infusion of angiotensin II by about 90% at peak plasma concentrations, with approximately 40% inhibition persisting for 24 hours. With chronic oral dosing, most of the antihypertensive effect is apparent within two weeks of initiation of the drug; however, maximum reduction in blood pressure may not be achieved for up to 4 weeks. The 24-hour trough-to-peak ratio for 40—80 mg oral doses of telmisartan is 70—100% for both systolic and diastolic blood pressure.
     
    Affected cytochrome P450 isoenzymes and drug transporters: CYP2C19
    Telmisartan has no effects in vitro on cytochrome P450 enzymes, except for some inhibition of CYP2C19. Therefore, it is not expected to interact with drugs metabolized by cytochrome P450 enzymes, except for possible inhibition of drugs metabolized by CYP2C19. No clinically significant interactions were noted when telmisartan was coadministered with acetaminophen, amlodipine, hydrochlorothiazide, ibuprofen, or simvastatin.

    Oral Route

    Following oral administration, peak concentrations are reached about 0.5—1 hour after dosing. The onset of antihypertensive activity occurs within 3 hours after administration of a single oral dose. The absolute bioavailability of telmisartan is dose-dependent. After administration of 40 mg and 160 mg, absolute bioavailability is about 42% and 58%, respectively. Food slightly reduces telmisartan bioavailability, with a reduction in the AUC of about 6% with the 40 mg tablet and about 20% after a 160 mg dose. The pharmacokinetics of telmisartan are nonlinear over the dose range of 20—160 mg, with greater than proportional increases of plasma concentrations (Cmax and AUC) with increasing doses.