Zaroxolyn

Browse PDR's full list of drug information

Zaroxolyn

Classes

Low Ceiling Diuretics, excluding Thiazides

Administration

NOTE: Metolazone is a potent diuretic. When used in combination with a loop diuretic, electrolyte loss can be severe. The smallest effective dose of metolazone should be determined.
 

Oral Administration

Metolazone is available as an oral formulation with rapid and complete absorption (Mykrox) and as a formulation with relatively slow and incomplete bioavailability (Zaroxolyn). Formulations bioequivalent to Mykrox should not be substituted for formulations bioequivalent to Zaroxolyn. NOTE: The Mykrox product formulation is no longer available in the US.
Due to the prolonged duration of action of Zaroxolyn, administer upon waking.

Adverse Reactions
Severe

aplastic anemia / Delayed / 0-1.0
agranulocytosis / Delayed / 0-1.0
toxic epidermal necrolysis / Delayed / 0-1.0
Stevens-Johnson syndrome / Delayed / 0-1.0
azotemia / Delayed / Incidence not known
thrombosis / Delayed / Incidence not known
visual impairment / Early / Incidence not known
pancreatitis / Delayed / Incidence not known
vasculitis / Delayed / Incidence not known
exfoliative dermatitis / Delayed / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known

Moderate

hyperuricemia / Delayed / 10.0
orthostatic hypotension / Delayed / 1.0
hypochloremia / Delayed / Incidence not known
hypercalcemia / Delayed / Incidence not known
hypomagnesemia / Delayed / Incidence not known
hypophosphatemia / Delayed / Incidence not known
metabolic alkalosis / Delayed / Incidence not known
hyponatremia / Delayed / Incidence not known
hypokalemia / Delayed / Incidence not known
gout / Delayed / Incidence not known
glycosuria / Early / Incidence not known
hyperglycemia / Delayed / Incidence not known
hypertriglyceridemia / Delayed / Incidence not known
hypercholesterolemia / Delayed / Incidence not known
palpitations / Early / Incidence not known
hypovolemia / Early / Incidence not known
chest pain (unspecified) / Early / Incidence not known
depression / Delayed / Incidence not known
blurred vision / Early / Incidence not known
leukopenia / Delayed / Incidence not known
thrombocytopenia / Delayed / Incidence not known
constipation / Delayed / Incidence not known
hepatitis / Delayed / Incidence not known
elevated hepatic enzymes / Delayed / Incidence not known
sialadenitis / Delayed / Incidence not known
jaundice / Delayed / Incidence not known
impotence (erectile dysfunction) / Delayed / Incidence not known

Mild

arthralgia / Delayed / Incidence not known
muscle cramps / Delayed / Incidence not known
myalgia / Early / Incidence not known
syncope / Early / Incidence not known
vertigo / Early / Incidence not known
anxiety / Delayed / Incidence not known
insomnia / Early / Incidence not known
asthenia / Delayed / Incidence not known
paresthesias / Delayed / Incidence not known
drowsiness / Early / Incidence not known
restlessness / Early / Incidence not known
abdominal pain / Early / Incidence not known
diarrhea / Early / Incidence not known
dysgeusia / Early / Incidence not known
xerostomia / Early / Incidence not known
anorexia / Delayed / Incidence not known
dyspepsia / Early / Incidence not known
nausea / Early / Incidence not known
vomiting / Early / Incidence not known
petechiae / Delayed / Incidence not known
rash / Early / Incidence not known
purpura / Delayed / Incidence not known
pruritus / Rapid / Incidence not known
urticaria / Rapid / Incidence not known
photosensitivity / Delayed / Incidence not known
polyuria / Early / Incidence not known

Common Brand Names

Zaroxolyn

Dea Class

Rx

Description

Oral quinazoline diuretic; used for edema and HTN; sulfonamide derivative; may produce diuresis in patients with impaired renal function; Zaroxolyn® is a formulation with relatively slow and incomplete absorption. Mykrox®, a more rapidly absorbed product with enhanced bioavailability, is no longer available in the US.

Dosage And Indications
For the treatment of hypertension. Oral dosage (Zaroxolyn or generic equivalent) Adults

2.5 to 5 mg PO once daily.

Geriatric

See adult dosage. Geriatric patients may be more sensitive to the effects of the usual adult dosage.

Children

0.2 to 0.4 mg/kg/day PO, given in divided doses every 12 to 24 hours.

Oral dosage (Mykrox formulation)

NOTE: This product formulation is no longer available in the US.

Adults

Initially, 0.5 mg PO once daily. Titrate dosage up to 1 mg PO once daily.

Geriatric

See adult dosage. Geriatric patients may be more sensitive to the effects of the usual adult dosage.

For the treatment of edema associated with congestive heart failure or renal diseases (e.g., nephrotic syndrome). Oral dosage (Zaroxolyn or generic equivalent) Adults

5 to 20 mg PO once daily. Heart failure guidelines recommend metolazone in combination with a loop diuretic for reduced ejection fraction heart failure (HFrEF) patients experiencing diuretic resistance.

Children†

One source recommends 0.2 to 0.4 mg/kg/day PO in 1 to 2 divided doses. The manufacturer reports limited experience with metolazone in doses ranging from 0.05 to 0.1 mg/kg PO once daily in children with heart failure, hypertension, bronchopulmonary dysplasia, nephrotic syndrome, and nephrogenic diabetes insipidus. According to the manufacturer, prolonged use (beyond a few days) is generally not associated with further benefit and is not recommended.

Infants†

One small study reports the use of 0.2 mg/kg metolazone given enterally with or without furosemide to infants with bronchopulmonary dysplasia. Urinary flow rate and urinary excretion of sodium, chloride, and potassium were greater with the combination of metolazone and furosemide than with administration of furosemide alone.

Dosing Considerations
Hepatic Impairment

No specific dosage adjustment is specified by the manufacturer due to limited data. Use with caution in patients with hepatic disease since minor alterations of fluid and electrolyte balance may precipitate hepatic coma.

Renal Impairment

No dosage adjustment is needed; however, higher doses may be needed to achieve clinical goals in some patients with end-stage renal disease.
 
Intermittent hemodialysis
No dosage adjustment is needed.

Drug Interactions

Acarbose: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Acetaminophen; Caffeine; Dihydrocodeine: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Acetaminophen; Codeine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Acetaminophen; Dichloralphenazone; Isometheptene: (Major) 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 diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Acetaminophen; Hydrocodone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and hydrocodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Acetaminophen; Ibuprofen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Acetaminophen; Oxycodone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and oxycodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Acetaminophen; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Acetaminophen; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Acetazolamide: (Moderate) Acetazolamide promotes electrolyte excretion including hydrogen ions, sodium, and potassium. It can enhance the sodium depleting effects of other diuretics when used concurrently. Pre-existing hypokalemia and hyperuricemia can also be potentiated by carbonic anhydrase inhibitors. Monitor serum potassium to determine the need for potassium supplementation and alteration in drug therapy.
Aclidinium; Formoterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Acrivastine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Albuterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Albuterol; Budesonide: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Aldesleukin, IL-2: (Moderate) Thiazide diuretics 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.
Alendronate; Cholecalciferol: (Moderate) Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with thiazide diuretics. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia. Hypercalcemia may be exacerbated by coadministration of vitamin D or vitamin D analogs and thiazide diuretics. Thiazide diuretics are known to induce hypercalcemia by reducing the excretion of calcium in the urine.
Alfentanil: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when a thiazide diuretic is administered with alfentanil. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
Allopurinol: (Moderate) Monitor renal function and for signs and symptoms of hypersensitivity and skin rash during concomitant use of allopurinol and thiazide diuretics; reduce the allopurinol dose in persons with renal impairment and concomitant thiazide diuretic use. Concomitant use may increase the risk of severe skin rash and renal impairment may further increase the risk. Discontinue allopurinol at the first appearance of skin rash or other signs which may indicate a hypersensitivity when using these drugs concomitantly.
Alogliptin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Alogliptin; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Alogliptin; Pioglitazone: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Alpha-glucosidase Inhibitors: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Alprostadil: (Minor) The concomitant use of systemic alprostadil injection and antihypertensive agents, such as thiazide diuretics, 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. In addition, the presence of medications in the circulation that attenuate erectile function may influence the response to alprostadil. 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 antihypertensive agents should be closely monitored during amifostine infusions due to additive effects. If possible, patients should not take their antihypertensive medication 24 hours before receiving amifostine. Patients who can not stop their antihypertensive agents should not receive amifostine or be closely monitored during the infusion and, possibly, given lower doses.
Aminolevulinic Acid: (Moderate) Thiazide diuretics may cause photosensitivity and may increase the photosensitization effects of photosensitizing agents used in photodynamic therapy. Prevention of photosensitivity includes adequate protection from sources of UV radiation (e.g., avoiding sun exposure and tanning booths) and the use of protective clothing and sunscreens on exposed skin.
Amlodipine; Benazepril: (Major) Discontinue the thiazide diuretic prior to starting benazepril, if possible, or start benazepril at the lower dose of 5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Amlodipine; Celecoxib: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Amoxicillin; Clarithromycin; Omeprazole: (Moderate) Monitor magnesium concentration before and periodically during concomitant omeprazole and thiazide diuretic use due to risk for hypomagnesemia.
Amphetamine; Dextroamphetamine Salts: (Minor) Amphetamines may counteract the activity of some antihypertensive agents, such as thiazide diuretics. Close monitoring of blood pressure is advised. Thiazide diuretics may also increase and prolong the actions of amphetamines by increasing the urinary pH.
Amphotericin B lipid complex (ABLC): (Moderate) The risk of developing severe hypokalemia can be increased when amphotericin B is coadministered with thiazide diuretics. Monitoring serum potassium levels and cardiac function is advised, and potassium supplementation may be required.
Amphotericin B liposomal (LAmB): (Moderate) The risk of developing severe hypokalemia can be increased when amphotericin B is coadministered with thiazide diuretics. Monitoring serum potassium levels and cardiac function is advised, and potassium supplementation may be required.
Amphotericin B: (Moderate) The risk of developing severe hypokalemia can be increased when amphotericin B is coadministered with thiazide diuretics. Monitoring serum potassium levels and cardiac function is advised, and potassium supplementation may be required.
Anticholinergics: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Apomorphine: (Moderate) Use of thiazide diuretics and apomorphine together can increase the hypotensive effects of apomorphine. Monitor blood pressure regularly during use of this combination.
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.
Arformoterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Aripiprazole: (Minor) Aripiprazole may enhance the hypotensive effects of antihypertensive agents.
Arsenic Trioxide: (Moderate) Concomitant use of thiazide diuretics and arsenic trioxide should be done cautiously. Electrolyte abnormalities, such as hypokalemia and hypomagnesemia, may increase the risk for QT prolongation and torsade de pointes.
Articaine; Epinephrine: (Moderate) Monitor blood pressure and heart rate during concomitant epinephrine and thiazide diuretic use. Thiazide diuretics may antagonize the pressor effects and potentiate the arrhythmogenic effects of epinephrine.
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.
Aspirin, ASA; Carisoprodol; Codeine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Aspirin, ASA; Omeprazole: (Moderate) Monitor magnesium concentration before and periodically during concomitant omeprazole and thiazide diuretic use due to risk for hypomagnesemia.
Aspirin, ASA; Oxycodone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and oxycodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Atracurium: (Moderate) Concomitant use of neuromuscular blockers and thiazide diuretics may prolong neuromuscular blockade, possibly due to hypokalemia or alterations in potassium concentrations across the end-plate membrane.
Atropine: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Atropine; Difenoxin: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
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.
Barbiturates: (Moderate) Barbiturates may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
Belladonna; Opium: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with opium. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone. (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Benazepril: (Major) Discontinue the thiazide diuretic prior to starting benazepril, if possible, or start benazepril at the lower dose of 5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Benazepril; Hydrochlorothiazide, HCTZ: (Major) Discontinue the thiazide diuretic prior to starting benazepril, if possible, or start benazepril at the lower dose of 5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Benzhydrocodone; Acetaminophen: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with benzhydrocodone. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Moderate) Thiazide diuretics may cause the urine to become alkaline. This may reduce the effectiveness of methenamine by inhibiting its conversion to formaldehyde. (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Benzphetamine: (Minor) Amphetamines may counteract the activity of some antihypertensive agents, such as thiazide diuretics. Close monitoring of blood pressure is advised. Thiazide diuretics may also increase and prolong the actions of amphetamines by increasing the urinary pH.
Benztropine: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Beta-agonists: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Bortezomib: (Moderate) Patients on antihypertensive agents receiving bortezomib treatment may require close monitoring of their blood pressure and dosage adjustment of their medication. During clinical trials of bortezomib, hypotension was reported in roughly 12 percent of patients.
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; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Brompheniramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Brompheniramine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Budesonide; Formoterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Budesonide; Glycopyrrolate; Formoterol: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms. (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Bupivacaine; Epinephrine: (Moderate) Monitor blood pressure and heart rate during concomitant epinephrine and thiazide diuretic use. Thiazide diuretics may antagonize the pressor effects and potentiate the arrhythmogenic effects of epinephrine.
Bupivacaine; Meloxicam: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Buprenorphine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and buprenorphine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Buprenorphine; Naloxone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and buprenorphine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Butalbital; Acetaminophen; Caffeine; Codeine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Butalbital; Aspirin; Caffeine; Codeine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Cabergoline: (Moderate) Cabergoline should be used cautiously with antihypertensive agents, including thiazide diuretics. Cabergoline has been associated with hypotension. Initial doses of cabergoline higher than 1 mg may produce orthostatic hypotension. It may be advisable to monitor blood pressure.
Calcium Phosphate, Supersaturated: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
Calcium: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
Calcium; Vitamin D: (Moderate) Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with thiazide diuretics. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia. Hypercalcemia may be exacerbated by coadministration of vitamin D or vitamin D analogs and thiazide diuretics. Thiazide diuretics are known to induce hypercalcemia by reducing the excretion of calcium in the urine.
Canagliflozin: (Major) Assess and correct volume status before initiating canagliflozin in persons receiving concomitant thiazide diuretics. Monitor for signs and symptoms of volume depletion and loss of glycemic control after initiating therapy due to increased risk for volume depletion or hypotension and loss of blood glucose control. Persons receiving thiazide diuretics may be at increased risk for volume depletion or hypotension with concomitant canagliflozin therapy. Thiazide diuretics tend to produce hyperglycemia and may lead to loss of glycemic control.
Canagliflozin; Metformin: (Major) Assess and correct volume status before initiating canagliflozin in persons receiving concomitant thiazide diuretics. Monitor for signs and symptoms of volume depletion and loss of glycemic control after initiating therapy due to increased risk for volume depletion or hypotension and loss of blood glucose control. Persons receiving thiazide diuretics may be at increased risk for volume depletion or hypotension with concomitant canagliflozin therapy. Thiazide diuretics tend to produce hyperglycemia and may lead to loss of glycemic control. (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
Captopril: (Major) Discontinue the thiazide diuretic prior to starting captopril, if possible, or start captopril at the lower dose of 6.25 or 12.5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Captopril; Hydrochlorothiazide, HCTZ: (Major) Discontinue the thiazide diuretic prior to starting captopril, if possible, or start captopril at the lower dose of 6.25 or 12.5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Carbamazepine: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant use of carbamazepine and thiazide diuretics due to additive risk of developing hyponatremia.
Carbidopa; Levodopa: (Moderate) Monitor blood pressure during concomitant levodopa and thiazide diuretic use due to risk for additive hypotension; a thiazide diuretic dosage adjustment may be necessary. Symptomatic postural hypotension has occurred when carbidopa; levodopa was added in a person receiving antihypertensive drugs.
Carbidopa; Levodopa; Entacapone: (Moderate) Monitor blood pressure during concomitant levodopa and thiazide diuretic use due to risk for additive hypotension; a thiazide diuretic dosage adjustment may be necessary. Symptomatic postural hypotension has occurred when carbidopa; levodopa was added in a person receiving antihypertensive drugs.
Cardiac glycosides: (Moderate) Monitor serum magnesium and potassium during concomitant cardiac glycoside and thiazide diuretic use. Potassium-depleting diuretics are a major contributing factor to digoxin toxicity.
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.
Celecoxib: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Celecoxib; Tramadol: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and tramadol; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Cetirizine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Chlordiazepoxide; Clidinium: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Chloroprocaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents.
Chlorpheniramine; Codeine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Chlorpheniramine; Hydrocodone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and hydrocodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics. (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Chlorpheniramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Chlorpheniramine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Chlorpropamide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Cholestyramine: (Moderate) Cholestyramine, an ion exchange resin, binds hydrochlorothiazide and reduces its absorption from the gastrointestinal tract by up to 85% when co-administered as single doses. Although the manufacturer for Questran recommends that other medicines be taken at least 1 hour before or 4-6 hours after cholestyramine, it has been recommended that thiazides be administered at least 4 hours before or after cholestyramine to minimize the reduction in absorption. By administering hydrochlorothiazide at least 4 hours before cholestyramine, the decrease in absorption of hydrochlorothiazide is approximately 30-35%.
Cidofovir: (Contraindicated) The administration of cidofovir with another potentially nephrotoxic agent, such as diuretics, is contraindicated. Diuretics should be discontinued at least 7 days prior to beginning cidofovir.
Cisapride: (Major) Cisapride should be used with great caution in patients receiving thiazide diuretics. Drugs that are associated with depletion of electrolytes may cause cisapride-induced cardiac arrhythmias. Serum electrolytes and creatinine should be assessed prior to administration of cisapride and whenever conditions develop that may affect electrolyte imbalance or renal function.
Cisatracurium: (Moderate) Concomitant use of neuromuscular blockers and thiazide diuretics may prolong neuromuscular blockade, possibly due to hypokalemia or alterations in potassium concentrations across the end-plate membrane.
Citalopram: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and citalopram use; consider discontinuing citalopram if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Clindamycin; Tretinoin: (Moderate) A manufacturer of topical tretinoin states that tretinoin, ATRA should be administered with caution in patients who are also taking drugs known to be photosensitizers, such as thiazide diuretics, as concomitant use may augment phototoxicity. Patients should take care and use proper techniques to limit sunlight and UV exposure of treated areas.
Clozapine: (Moderate) Caution is advisable during concurrent use of clozapine and thiazide diuretics as concurrent use may increase the risk and severity of hypotension. In addition, electrolyte imbalance caused by thiazide diuretics may increase the risk of QT prolongation by clozapine.
Cocaine: (Major) Use of cocaine with antihypertensive agents may increase the antihypertensive effects of the antihypertensive medications or may potentiate cocaine-induced sympathetic stimulation.
Codeine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Codeine; Guaifenesin: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Codeine; Guaifenesin; Pseudoephedrine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic. (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Codeine; Phenylephrine; Promethazine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Codeine; Promethazine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Co-Enzyme Q10, Ubiquinone: (Moderate) Monitor blood pressure during concomitant co-enzyme Q10 (ubiquinone) and thiazide diuretic use. Concomitant use may result in additive hypotension.
Colestipol: (Moderate) Although to a lesser extent than cholestyramine, colestipol also has been shown to inhibit the GI absorption and therapeutic response of thiazide diuretics. Single doses of colestipol resins reduce the absorption of HCTZ by up to 43%. Administering thiazide diuretics at least 2 hours before colestipol has been suggested to minimize the interaction.
Corticosteroids: (Moderate) Monitor potassium concentrations during concomitant corticosteroid and thiazide diuretic use due to risk for additive hypokalemia; potassium supplementation may be necessary. Both corticosteroids and thiazide diuretics cause increased renal potassium loss.
Corticotropin, ACTH: (Minor) Monitor potassium concentrations during concomitant corticotropin and thiazide diuretic use due to risk for additive hypokalemia; potassium supplementation may be necessary. Both corticotropin and thiazide diuretics cause increased renal potassium loss.
Cosyntropin: (Moderate) Use cosyntropin cautiously in patients receiving diuretics. Cosyntropin may accentuate the electrolyte loss associated with diuretic therapy.
Cyclophosphamide: (Moderate) Closely monitor complete blood counts if coadministration of cyclophosphamide with thiazide diuretics is necessary as there is an increased risk of hematologic toxicity and immunosuppression.
Dapagliflozin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Dapagliflozin; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Dapagliflozin; Saxagliptin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Desloratadine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Desmopressin: (Moderate) Monitor serum sodium more frequently during concomitant desmopressin and thiazide diuretic use due to increased risk of water intoxication with hyponatremia.
Desvenlafaxine: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and serotonin norepinephrine reuptake inhibitor (SNRI) use; consider discontinuing the SNRI if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Dexbrompheniramine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Dexlansoprazole: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
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) Enhanced hyperglycemia is possible during concurrent use of diazoxide and thiazide diuretics. Additive hypotensive effects can also occur with the concomitant administration of diazoxide with thiazide diuretics.
Dichlorphenamide: (Moderate) Use dichlorphenamide and diuretics together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including loop diuretics and thiazide diuretics. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
Diclofenac: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Diclofenac; Misoprostol: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Dicyclomine: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Diethylpropion: (Major) Diethylpropion has vasopressor effects and may limit the benefit of thiazide diuretics. 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.
Diflunisal: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Digoxin: (Moderate) Monitor serum magnesium and potassium during concomitant cardiac glycoside and thiazide diuretic use. Potassium-depleting diuretics are a major contributing factor to digoxin toxicity.
Diphenhydramine; Ibuprofen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensat

ion, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Diphenhydramine; Naproxen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Diphenhydramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Diphenoxylate; Atropine: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Dobutamine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives such as metolazone when administered concomitantly.
Dofetilide: (Contraindicated) Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs such as loop diuretics and thiazide diuretics, increasing the potential for dofetilide-induced torsade de pointes. Additionally, in patients treated with either hydrochlorothiazide 50 mg or hydrochlorothiazide/triamterene 50 mg/100 mg daily in combination with dofetilide 500 mcg twice daily for 5 days, dofetilide AUC and Cmax concentrations increased by 27% and 21%, respectively, for the hydrochlorothiazide alone group and by 30% and 16%, respectively, for the hydrochlorothiazide/triamterene group. Furthermore, a 197% and 190% QTc increase over time was seen in the hydrochlorothiazide and hydrochlorothiazide/triamterene groups, respectively. Based on these findings, the manufacturer of dofetilide contraindicates the concomitant use of hydrochlorothiazide (alone or in combination with other drugs such as triamterene); these findings can be explained both by an increase in the plasma concentration of dofetilide and a reduction in the serum potassium concentration. In a population pharmacokinetic analysis of plasma dofetilide concentrations, the mean dofetilide clearance of dofetilide was 16% lower in patients on thiazide diuretics. It is prudent to avoid the use of any thiazide diuretic in combination with dofetilide.
Dolasetron: (Moderate) Caution is advisable during concurrent use of dolasetron and thiazide diuretics as electrolyte imbalance caused by diuretics may increase the risk of QT prolongation with dolasetron.
Dopamine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives such as metolazone when administered concomitantly.
Droperidol: (Moderate) Caution is advised when using droperidol in combination with thiazide diuretics which may lead to electrolyte abnormalities, especially hypokalemia or hypomagnesemia, as such abnormalities may increase the risk for QT prolongation or cardiac arrhythmias.
Dulaglutide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Duloxetine: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and serotonin norepinephrine reuptake inhibitor (SNRI) use; consider discontinuing the SNRI if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Empagliflozin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Empagliflozin; Linagliptin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Empagliflozin; Linagliptin; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Empagliflozin; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Enalapril, Enalaprilat: (Major) Discontinue the thiazide diuretic prior to starting enalapril, if possible, or start enalapril at the lower dose of 2.5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Enalapril; Hydrochlorothiazide, HCTZ: (Major) Discontinue the thiazide diuretic prior to starting enalapril, if possible, or start enalapril at the lower dose of 2.5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Ephedrine: (Major) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by thiazide diuretics. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved.
Ephedrine; Guaifenesin: (Major) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by thiazide diuretics. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved.
Epinephrine: (Moderate) Monitor blood pressure and heart rate during concomitant epinephrine and thiazide diuretic use. Thiazide diuretics may antagonize the pressor effects and potentiate the arrhythmogenic effects of epinephrine.
Ertugliflozin; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
Ertugliflozin; Sitagliptin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Escitalopram: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and escitalopram use; consider discontinuing escitalopram if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Esomeprazole: (Moderate) Monitor magnesium concentration before and periodically during concomitant esomeprazole and thiazide diuretic use due to risk for hypomagnesemia.
Estradiol: (Minor) Estrogens can induce fluid retention and may increase blood pressure in some patients; patients who are receiving antihypertensive agents concurrently with hormone therapy should be monitored for antihypertensive effectiveness.
Ethanol: (Major) Advise patients to avoid alcohol while taking thiazide diuretics. Ingesting alcohol can increase the risk for orthostatic hypotension when taking a thiazide diuretic.
Etodolac: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Etomidate: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Exenatide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Fenoprofen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Fentanyl: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and fentanyl; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Fexofenadine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Fish Oil, Omega-3 Fatty Acids (Dietary Supplements): (Moderate) Monitor blood pressure during concomitant fish oil and thiazide diuretic use. Concomitant use may result in additive hypotension; high doses of fish oil may produce a blood pressure lowering effect.
Flavoxate: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Fluocinolone; Hydroquinone; Tretinoin: (Moderate) A manufacturer of topical tretinoin states that tretinoin, ATRA should be administered with caution in patients who are also taking drugs known to be photosensitizers, such as thiazide diuretics, as concomitant use may augment phototoxicity. Patients should take care and use proper techniques to limit sunlight and UV exposure of treated areas.
Fluoxetine: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and fluoxetine use; consider discontinuing fluoxetine if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Flurbiprofen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Fluticasone; Salmeterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Fluticasone; Umeclidinium; Vilanterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Fluticasone; Vilanterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Fluvoxamine: (Moderate) Patients receiving a diuretic during treatment with fluvoxamine may be at greater risk of developing syndrome of inappropriate antidiuretic hormone secretion (SIADH). Hyponatremia due to SIADH has been reported during therapy with SSRIs. Cases involving serum sodium levels lower than 110 mmol/L have occurred. Hyponatremia may be potentiated by agents which can cause sodium depletion such as diuretics. Discontinuation of fluvoxamine should be considered in patients who develop symptomatic hyponatremia.
Formoterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Formoterol; Mometasone: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Fosinopril: (Major) Discontinue the thiazide diuretic prior to starting fosinopril, if possible, or start fosinopril at a lower dose to minimize hypotension. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Fosinopril; Hydrochlorothiazide, HCTZ: (Major) Discontinue the thiazide diuretic prior to starting fosinopril, if possible, or start fosinopril at a lower dose to minimize hypotension. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
General anesthetics: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Glimepiride: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Glipizide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Glipizide; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Glyburide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Glyburide; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Glycopyrrolate: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Glycopyrrolate; Formoterol: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms. (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Granisetron: (Moderate) According to the manufacturer, caution is warranted when administering granisetron to patients with preexisting electrolyte abnormalities. Patients taking certain diuretics may develop an electrolyte abnormality that may lead to cardiac dysrhythmias and/or QT prolongation. Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs such as loop diuretics and thiazide diuretics, increasing the potential for cardiac arrhythmias.
Guaifenesin; Hydrocodone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and hydrocodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Guaifenesin; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Halobetasol; Tazarotene: (Moderate) The manufacturer states that tazarotene should be administered with caution in patients who are also taking drugs known to be photosensitizers, such as thiazide diuretics, as concomitant use may augment phototoxicity. Patients should take care and use proper techniques to limit sunlight and UV exposure of treated areas.
Haloperidol: (Moderate) Caution is advisable during concurrent use of haloperidol and thiazide diuretics as electrolyte imbalance caused by diuretics may increase the risk of QT prolongation with haloperidol. Concomitant use may also cause additive hypotension.
Homatropine; Hydrocodone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and hydrocodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic. (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Hydralazine; Isosorbide Dinitrate, ISDN: (Moderate) Monitor blood pressure during concomitant thiazide diuretic and nitrate use due to risk for additive hypotension.
Hydrochlorothiazide, HCTZ; Moexipril: (Major) Discontinue the thiazide diuretic prior to starting moexipril, if possible, or start moexipril at the lower dose of 3.75 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Hydrocodone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and hydrocodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Hydrocodone; Ibuprofen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and hydrocodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Hydrocodone; Pseudoephedrine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and hydrocodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic. (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Hydromorphone: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with hydromorphone. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
Hyoscyamine: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Moderate) Thiazide diuretics may cause the urine to become alkaline. This may reduce the effectiveness of methenamine by inhibiting its conversion to formaldehyde. (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Ibuprofen lysine: (Moderate) Ibuprofen lysine may reduce the effect of diuretics; diuretics can increase the risk of nephrotoxicity of NSAIDs in dehydrated patients. During coadministration of NSAIDs and diuretic therapy, patients should be monitored for changes in the effectiveness of their diuretic therapy and for signs and symptoms of renal impairment.
Ibuprofen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Ibuprofen; Famotidine: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Ibuprofen; Oxycodone: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and oxycodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Ibuprofen; Pseudoephedrine: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics. (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Icosapent ethyl: (Moderate) Thiazide diuretics may exacerbate hypertriglyceridemia and should be discontinued or changed to alternate therapy, if possible, prior to initiation of icosapent ethyl.
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.
Incretin Mimetics: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Indacaterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Indacaterol; Glycopyrrolate: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms. (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Indomethacin: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Inotersen: (Moderate) Use caution with concomitant use of inotersen and diuretics due to the risk of glomerulonephritis and nephrotoxicity.
Insulin Degludec; Liraglutide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Insulin Glargine; Lixisenatide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Insulins: (Moderate) Monitor patients receiving insulin closely for changes in diabetic control when thiazide diuretics are instituted or discontinued; dosage adjustments may be required. Thiazide diuretics can decrease the hypoglycemic effects of insulin by producing an increase in blood glucose levels. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes.
Intravenous Lipid Emulsions: (Moderate) Monitor blood pressure during concomitant fish oil and thiazide diuretic use. Concomitant use may result in additive hypotension; high doses of fish oil may produce a blood pressure lowering effect.
Ipratropium; Albuterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Isocarboxazid: (Moderate) Additive hypotensive effects may be seen when monoamine oxidase inhibitors (MAOIs) are combined with antihypertensives. Careful monitoring of blood pressure is suggested during concurrent therapy of MAOIs with diuretics. 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.
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) Monitor blood pressure during concomitant thiazide diuretic and nitrate use due to risk for additive hypotension.
Isosorbide Mononitrate: (Moderate) Monitor blood pressure during concomitant thiazide diuretic and nitrate use due to risk for additive hypotension.
Ketamine: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Ketoprofen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Ketorolac: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Lansoprazole: (Moderate) Monitor magnesium concentration before and periodically during concomitant lansoprazole and thiazide diuretic use due to risk for hypomagnesemia.
Lansoprazole; Amoxicillin; Clarithromycin: (Moderate) Monitor magnesium concentration before and periodically during concomitant lansoprazole and thiazide diuretic use due to risk for hypomagnesemia.
Lesinurad; Allopurinol: (Moderate) Monitor renal function and for signs and symptoms of hypersensitivity and skin rash during concomitant use of allopurinol and thiazide diuretics; reduce the allopurinol dose in persons with renal impairment and concomitant thiazide diuretic use. Concomitant use may increase the risk of severe skin rash and renal impairment may further increase the risk. Discontinue allopurinol at the first appearance of skin rash or other signs which may indicate a hypersensitivity when using these drugs concomitantly.
Levalbuterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Levodopa: (Moderate) Monitor blood pressure during concomitant levodopa and thiazide diuretic use due to risk for additive hypotension; a thiazide diuretic dosage adjustment may be necessary. Symptomatic postural hypotension has occurred when carbidopa; levodopa was added in a person receiving antihypertensive drugs.
Levomilnacipran: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and serotonin norepinephrine reuptake inhibitor (SNRI) use; consider discontinuing the SNRI if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Levorphanol: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with levorphanol. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
Lidocaine; Epinephrine: (Moderate) Monitor blood pressure and heart rate during concomitant epinephrine and thiazide diuretic use. Thiazide diuretics may antagonize the pressor effects and potentiate the arrhythmogenic effects of epinephrine.
Linagliptin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Linagliptin; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Liraglutide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Lisdexamfetamine: (Minor) Amphetamines may counteract the activity of some antihypertensive agents, such as thiazide diuretics. Close monitoring of blood pressure is advised. Thiazide diuretics may also increase and prolong the actions of amphetamines by increasing the urinary pH.
Lisinopril: (Major) Discontinue the thiazide diuretic prior to starting lisinopril, if possible, or start lisinopril at the lower dose of 5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Lisinopril; Hydrochlorothiazide, HCTZ: (Major) Discontinue the thiazide diuretic prior to starting lisinopril, if possible, or start lisinopril at the lower dose of 5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Lithium: (Moderate) Monitor lithium concentrations during concomitant use with thiazide diuretics; consider lower lithium starting doses and titrating slowly while frequently monitoring lithium concentrations and for signs of lithium toxicity. Thiazide diuretics reduce the renal clearance of lithium and increase the risk for lithium toxicity.
Lixisenatide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Loop diuretics: (Moderate) Monitor blood pressure, renal function, and serum electrolytes during concomitant loop diuretic and thiazide diuretic use; dosage adjustments may be necessary. Concomitant use may result in additive hypotension and fluid and/or electrolyte loss.
Loratadine; Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
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 diuretics.
Mannitol: (Major) Avoid use of other diuretics with mannitol, if possible. Concomitant administration may potentiate the renal toxicity of mannitol.
Meclofenamate Sodium: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Mefenamic Acid: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Meglitinides: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Meloxicam: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Meperidine: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with meperidine. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
Metaproterenol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
Metformin; Repaglinide: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effect s on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Metformin; Rosiglitazone: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Metformin; Saxagliptin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Metformin; Sitagliptin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Methadone: (Moderate) Diuretics can cause electrolyte disturbances such as hypomagnesemia and hypokalemia, which may prolong the QT interval. As methadone may also prolong the QT interval, cautious coadministration with diuretics is needed. In addition, opiate agonists may potentiate orthostatic hypotension when used concurrently with diuretics.
Methamphetamine: (Minor) Amphetamines may counteract the activity of some antihypertensive agents, such as thiazide diuretics. Close monitoring of blood pressure is advised. Thiazide diuretics may also increase and prolong the actions of amphetamines by increasing the urinary pH.
Methazolamide: (Moderate) Thiazide diuretics may increase the risk of hypokalemia if used concurrently with methazolamide. Monitor serum potassium levels to determine the need for potassium supplementation and/or alteration in drug therapy. There may also be an additive diuretic or hyperuricemic effect.
Methenamine: (Moderate) Thiazide diuretics may cause the urine to become alkaline. This may reduce the effectiveness of methenamine by inhibiting its conversion to formaldehyde.
Methenamine; Sodium Acid Phosphate: (Moderate) Thiazide diuretics may cause the urine to become alkaline. This may reduce the effectiveness of methenamine by inhibiting its conversion to formaldehyde.
Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Moderate) Thiazide diuretics may cause the urine to become alkaline. This may reduce the effectiveness of methenamine by inhibiting its conversion to formaldehyde. (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Methenamine; Sodium Salicylate: (Moderate) Thiazide diuretics may cause the urine to become alkaline. This may reduce the effectiveness of methenamine by inhibiting its conversion to formaldehyde.
Methotrexate: (Moderate) Monitor for increased methotrexate-related adverse reactions during concomitant thiazide diuretic use. Thiazide diuretics may decrease renal excretion of cytotoxic agents and enhance their myelosuppressive effects.
Methoxsalen: (Moderate) Concomitant administration of methoxsalen and other photosensitizing agents, such as thiazide diuretics, can increase the incidence or severity of photsensitization from either compound.
Methscopolamine: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Methylphenidate Derivatives: (Moderate) Monitor blood pressure during concomitant thiazide diuretic and methylphenidate use; a thiazide diuretic dose adjustment may be necessary. Methylphenidate may decrease the effectiveness of medications used to treat hypertension.
Metoclopramide: (Minor) Coadministration of thiazides and prokinetic agents may result in decreased bioavailability of the thiazide diuretic.
Midodrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Miglitol: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Milnacipran: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and serotonin norepinephrine reuptake inhibitor (SNRI) use; consider discontinuing the SNRI if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Milrinone: (Moderate) Concurrent administration of antihypertensive agents could lead to additive hypotension when administered with milrinone. Titrate milrinone dosage according to hemodynamic response.
Mirtazapine: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and mirtazapine use; consider discontinuing mirtazapine if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Mivacurium: (Moderate) Concomitant use of neuromuscular blockers and thiazide diuretics may prolong neuromuscular blockade, possibly due to hypokalemia or alterations in potassium concentrations across the end-plate membrane.
Moexipril: (Major) Discontinue the thiazide diuretic prior to starting moexipril, if possible, or start moexipril at the lower dose of 3.75 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Morphine: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and morphine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Morphine; Naltrexone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and morphine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Nabumetone: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Naproxen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Naproxen; Esomeprazole: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics. (Moderate) Monitor magnesium concentration before and periodically during concomitant esomeprazole and thiazide diuretic use due to risk for hypomagnesemia.
Naproxen; Pseudoephedrine: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics. (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Nateglinide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Nefazodone: (Minor) Although relatively infrequent, nefazodone may cause orthostatic hypotension in some patients; this effect may be additive with antihypertensive agents. Blood pressure monitoring and dosage adjustments of either drug may be necessary.
Neostigmine; Glycopyrrolate: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Nesiritide, BNP: (Moderate) The potential for hypotension may be increased when coadministering nesiritide with antihypertensive agents.
Neuromuscular blockers: (Moderate) Concomitant use of neuromuscular blockers and thiazide diuretics may prolong neuromuscular blockade, possibly due to hypokalemia or alterations in potassium concentrations across the end-plate membrane.
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) Monitor blood pressure during concomitant thiazide diuretic and nitrate use due to risk for additive hypotension.
Nitroglycerin: (Moderate) Monitor blood pressure during concomitant thiazide diuretic and nitrate use due to risk for additive hypotension.
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.
Non-Ionic Contrast Media: (Major) Do not use diuretics before non-ionic contrast media administration. Concomitant use of diuretics and non-ionic contrast media may increase the risk for acute kidney injury, including renal failure.
Nonsteroidal antiinflammatory drugs: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Norepinephrine: (Moderate) Thiazide diuretics can cause decreased arterial responsiveness to norepinephrine, but the effect is not sufficient to preclude their coadministration.
Octreotide: (Moderate) Patients receiving diuretics or other agents to control fluid and electrolyte balance may require dosage adjustments while receiving octreotide due to additive effects.
Olanzapine: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
Olanzapine; Fluoxetine: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and fluoxetine use; consider discontinuing fluoxetine if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia. (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
Olanzapine; Samidorphan: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
Oliceridine: (Moderate) Monitor patients for signs of diminished diuresis and/or effects on blood pressure if diuretics are used concomitantly with oliceridine; increase the dosage of the diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone.
Olodaterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Omeprazole: (Moderate) Monitor magnesium concentration before and periodically during concomitant omeprazole and thiazide diuretic use due to risk for hypomagnesemia.
Omeprazole; Amoxicillin; Rifabutin: (Moderate) Monitor magnesium concentration before and periodically during concomitant omeprazole and thiazide diuretic use due to risk for hypomagnesemia.
Omeprazole; Sodium Bicarbonate: (Moderate) Monitor magnesium concentration before and periodically during concomitant omeprazole and thiazide diuretic use due to risk for hypomagnesemia.
Oxaprozin: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Oxybutynin: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Oxycodone: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and oxycodone; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Oxymetazoline: (Major) The vasoconstricting actions of oxymetazoline, an alpha adrenergic agonist, may reduce the antihypertensive effects produced by diuretics. If these drugs are used together, closely monitor for changes in blood pressure.
Oxymorphone: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with oxymorphone. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
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 thiazide diuretics who are susceptible to hypotension.
Pancuronium: (Moderate) Concomitant use of neuromuscular blockers and thiazide diuretics may prolong neuromuscular blockade, possibly due to hypokalemia or alterations in potassium concentrations across the end-plate membrane.
Pantoprazole: (Moderate) Monitor magnesium concentration before and periodically during concomitant pantoprazole and thiazide diuretic use due to risk for hypomagnesemia.
Paroxetine: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and paroxetine use; consider discontinuing paroxetine if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Pasireotide: (Moderate) Cautious use of pasireotide and thiazide diuretics is advised as electrolyte imbalance caused by diuretics may increase the risk of QT prolongation with pasireotide. Assess the patient's potassium and magnesium concentration before and periodically during pasireotide receipt. Correct hypokalemia and hypomagnesemia before pasireotide receipt.
Pentamidine: (Moderate) Drugs that are associated with hypokalemia and/or hypomagnesemia such as thiazide diuretics should be used with caution in patients also receiving pentamidine. Since pentamidine may cause QT prolongation independently of electrolyte imbalances, the risk for cardiac arrhythmias is potentiated by the concomitant use of agents associated with electrolyte loss. Closely monitor serum electrolytes during pentamidine therapy.
Pentazocine: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with pentazocine. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
Pentazocine; Naloxone: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with pentazocine. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
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.
Perindopril: (Major) Discontinue the thiazide diuretic prior to starting perindopril, if possible, or start perindopril at a lower dose to minimize hypotension. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Perindopril; Amlodipine: (Major) Discontinue the thiazide diuretic prior to starting perindopril, if possible, or start perindopril at a lower dose to minimize hypotension. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Phendimetrazine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Phenelzine: (Moderate) Monitor blood pressure during concomitant thiazide diuretic and phenelzine use due to risk for additive hypotension.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Phenothiazines: (Moderate) Monitor blood pressure during concomitant thiazide diuretic and phenothiazine use. Thiazide diuretics may potentiate the orthostatic hypotension that may occur with phenothiazines.
Phentermine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Phentermine; Topiramate: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Photosensitizing agents (topical): (Moderate) Thiazide diuretics may cause photosensitivity and may increase the photosensitization effects of photosensitizing agents used in photodynamic therapy. Prevention of photosensitivity includes adequate protection from sources of UV radiation (e.g., avoiding sun exposure and tanning booths) and the use of protective clothing and sunscreens on exposed skin.
Pimozide: (Moderate) Caution is advisable during concurrent use of pimozide and thiazide diuretics as electrolyte imbalance caused by diuretics may increase the risk of QT prolongation with pimozide. Potassium deficiencies should be corrected prior to treatment with pimozide and normalized potassium levels should be maintained during treatment.
Pioglitazone: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Pioglitazone; Glimepiride: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Pioglitazone; Metformin: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Piroxicam: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Polycarbophil: (Moderate) Coadministration may lead to hypercalcemia because thiazides cause a decrease in renal tubular excretion of calcium as well as increase in distal tubular reabsorption. Each 625 mg of calcium polycarbophil contains a substantial amount of calcium (approximately 125 mg). Moderate increases in serum calcium have been seen during the treatment with thiazides; if calcium polycarbophil is used concomitantly, monitoring of serum calcium may be prudent.
Polyethylene Glycol; Electrolytes: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as diuretics.
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 diuretics.
Porfimer: (Major) Avoid coadministration of porfimer with thiazide diuretics due to the risk of increased photosensitivity. Porfimer is a light-activated drug used in photodynamic therapy; all patients treated with porfimer will be photosensitive. Concomitant use of other photosensitizing agents like thiazide diuretics may increase the risk of a photosensitivity reaction.
Pramlintide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Prazosin: (Moderate) Prazosin 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.
Prilocaine; Epinephrine: (Moderate) Monitor blood pressure and heart rate during concomitant epinephrine and thiazide diuretic use. Thiazide diuretics may antagonize the pressor effects and potentiate the arrhythmogenic effects of epinephrine.
Probenecid: (Moderate) Thiazide diuretics can cause hyperuricemia. Although this effect represents a pharmacodynamic interaction and not a pharmacokinetic one, dosage adjustments of probenecid may be necessary if these agents are administered concurrently to patients being treated with probenecid.
Probenecid; Colchicine: (Moderate) Thiazide diuretics can cause hyperuricemia. Although this effect represents a pharmacodynamic interaction and not a pharmacokinetic one, dosage adjustments of probenecid may be necessary if these agents are administered concurrently to patients being treated with probenecid.
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.
Promethazine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by diuretics. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure has been reported in some patients.
Propantheline: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Propofol: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Pseudoephedrine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Pseudoephedrine; Triprolidine: (Moderate) Sympathomimetics can antagonize the effects of antihypertensives when administered concomitantly.
Quinapril: (Major) Discontinue the thiazide diuretic prior to starting quinapril, if possible, or start quinapril at the lower dose of 5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Quinapril; Hydrochlorothiazide, HCTZ: (Major) Discontinue the thiazide diuretic prior to starting quinapril, if possible, or start quinapril at the lower dose of 5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Quinidine: (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
Rabeprazole: (Moderate) Proton pump inhibitors have been associated with hypomagnesemia. Hypomagnesemia occurs with thiazide diuretics (chlorothiazide, hydrochlorothiazide, indapamide, and metolazone). Low serum magnesium may lead to serious adverse events such as muscle spasm, seizures, and arrhythmias. Therefore, clinicians should monitor serum magnesium concentrations periodically in patients taking a PPI and diuretics concomitantly. Patients who develop hypomagnesemia may require PPI discontinuation in addition to magnesium replacement.
Ramipril: (Major) Discontinue the thiazide diuretic prior to starting ramipril, if possible, or start ramipril at a lower dose to minimize hypotension. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Rasagiline: (Moderate) Additive hypotensive effects may be seen when monoamine oxidase inhibitors (MAOIs) are combined with antihypertensives. Careful monitoring of blood pressure is suggested during concurrent therapy of MAOIs with diuretics. 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.
Remifentanil: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
Repaglinide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Risperidone: (Moderate) Risperidone may induce orthostatic hypotension and thus enhance the hypotensive effects of antihypertensive agents. Lower initial doses or slower dose titration of risperidone may be necessary in patients receiving antihypertensive agents concomitantly.
Rocuronium: (Moderate) Concomitant use of neuromuscular blockers and thiazide diuretics may prolong neuromuscular blockade, possibly due to hypokalemia or alterations in potassium concentrations across the end-plate membrane.
Rosiglitazone: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Salicylates: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention.
Salmeterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Saxagliptin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Scopolamine: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Semaglutide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Serotonin norepinephrine reuptake inhibitors: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and serotonin norepinephrine reuptake inhibitor (SNRI) use; consider discontinuing the SNRI if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Sertraline: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and sertraline use; consider discontinuing sertraline if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Sevoflurane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
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.
Sitagliptin: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics, 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 diuretics. In addition, use caution in patients receiving drugs where hypokalemia is a particular risk.
Solifenacin: (Minor) Diuretics can increase urinary frequency, which may aggravate bladder symptoms. Risk versus benefit should be addressed in patients receiving diuretics and solifenacin.
Streptozocin: (Minor) Because streptozocin is nephrotoxic, concurrent or subsequent administration of other nephrotoxic agents (e.g., aminoglycosides, amphotericin B, cisplatin, foscarnet, or diuretics) could exacerbate the renal insult.
Succinylcholine: (Moderate) Concomitant use of neuromuscular blockers and thiazide diuretics may prolong neuromuscular blockade, possibly due to hypokalemia or alterations in potassium concentrations across the end-plate membrane.
Sufentanil: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with sufentanil. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
Sulfacetamide: (Moderate) Sulfonamides may cause photosensitization and may increase the photosensitizing effects of thiazide diuretics.
Sulfacetamide; Sulfur: (Moderate) Sulfonamides may cause photosensitization and may increase the photosensitizing effects of thiazide diuretics.
Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Major) Avoid the concomitant use of sulfamethoxazole; trimethoprim and thiazide diuretics. An increased incidence of thrombocytopenia with purpura has been reported in elderly patients during coadministration.
Sulfonylureas: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Sulindac: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Sumatriptan; Naproxen: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Tapentadol: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when thiazide diuretics are administered with tapentadol. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone.
Tazarotene: (Moderate) The manufacturer states that tazarotene should be administered with caution in patients who are also taking drugs known to be photosensitizers, such as thiazide diuretics, as concomitant use may augment phototoxicity. Patients should take care and use proper techniques to limit sunlight and UV exposure of treated areas.
Tegaserod: (Minor) Coadminisitration of thiazides and prokinetic agents may result in decreased bioavailability of the thiazide diuretic.
Terbutaline: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Tetrabenazine: (Moderate) Tetrabenazine may induce orthostatic hypotension and thus enhance the hypotensive effects of antihypertensive agents. Lower initial doses or slower dose titration of tetrabenazine may be necessary in patients receiving antihypertensive agents concomitantly.
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) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Thiothixene: (Moderate) Thiothixene should be used cautiously in patients receiving antihypertensive agents. Additive hypotensive effects are possible.
Tiotropium; Olodaterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Tirzepatide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary. Finally, both thiazides and sulfonylureas have been reported to cause photosensitivity reactions; concomitant use may increase the risk of photosensitivity.
Tizanidine: (Moderate) Monitor blood pressure during concomitant thiazide diuretic and tizanidine use due to risk for additive hypotension.
Tolazamide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Tolbutamide: (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
Tolmetin: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Tolterodine: (Minor) Diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Tolvaptan: (Moderate) Monitor serum sodium closely if tolvaptan and thiazide diuretics are used together. Coadministration increases the risk of too rapid correction of serum sodium.
Toremifene: (Moderate) Monitor serum calcium levels in patients receiving concomitant treatment with toremifene and thiazide diuretics. Thiazide diuretics decrease renal calcium excretion and may increase the risk of hypercalcemia in patients receiving toremifene.
Tramadol: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and tramadol; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Tramadol; Acetaminophen: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and tramadol; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Trandolapril: (Major) Discontinue the thiazide diuretic prior to starting trandolapril, if possible, or start trandolapril at the lower dose of 0.5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Trandolapril; Verapamil: (Major) Discontinue the thiazide diuretic prior to starting trandolapril, if possible, or start trandolapril at the lower dose of 0.5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Tranylcypromine: (Contraindicated) 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.
Treprostinil: (Moderate) Thiazide diuretics can enhance the hypotensive effects of antihypertensive agents or diuretics if given concomitantly. This additive effect may be desirable, but dosages must be adjusted accordingly.
Tretinoin, ATRA: (Moderate) A manufacturer of topical tretinoin states that tretinoin, ATRA should be administered with caution in patients who are also taking drugs known to be photosensitizers, such as thiazide diuretics, as concomitant use may augment phototoxicity. Patients should take care and use proper techniques to limit sunlight and UV exposure of treated areas.
Tretinoin; Benzoyl Peroxide: (Moderate) A manufacturer of topical tretinoin states that tretinoin, ATRA should be administered with caution in patients who are also taking drugs known to be photosensitizers, such as thiazide diuretics, as concomitant use may augment phototoxicity. Patients should take care and use proper techniques to limit sunlight and UV exposure of treated areas.
Trihexyphenidyl: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Trospium: (Minor) Diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Umeclidinium; Vilanterol: (Minor) Hypokalemia associated with thiazide diuretics can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is unknown, use caution when coadministering beta-agonists with thiazide diuretics and monitor serum potassium as clinically indicated.
Valdecoxib: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant nonsteroidal antiinflammatory drug (NSAID) and thiazide diuretic use. NSAIDs may cause a dose-dependent reduction in renal blood flow, which may precipitate overt renal decompensation, and concomitant diuretic use increases the risk of this reaction. NSAIDs have been shown to reduce the natriuretic effect of thiazide diuretics and are associated with fluid retention which may blunt the cardiovascular effects of diuretics.
Vecuronium: (Moderate) Concomitant use of neuromuscular blockers and thiazide diuretics may prolong neuromuscular blockade, possibly due to hypokalemia or alterations in potassium concentrations across the end-plate membrane.
Venlafaxine: (Moderate) Monitor for signs and symptoms of hyponatremia during concomitant diuretic and serotonin norepinephrine reuptake inhibitor (SNRI) use; consider discontinuing the SNRI if symptomatic hyponatremia occurs and institute appropriate medical intervention. Concomitant use increases the risk for developing hyponatremia.
Verteporfin: (Moderate) Use caution if coadministration of verteporfin with thiazide diuretics is necessary due to the risk of increased photosensitivity. Verteporfin is a light-activated drug used in photodynamic therapy; all patients treated with verteporfin will be photosensitive. Concomitant use of other photosensitizing agents like thiazide diuretics may increase the risk of a photosensitivity reaction.
Vilazodone: (Moderate) Patients receiving vilazodone with medications known to cause hyponatremia, such as diuretics, may be at increased risk of developing hyponatremia. Hyponatremia has occurred in association with the use of antidepressants such as selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), and mirtazapine. Hyponatremia may manifest as headache, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness which may result in falls. Severe manifestations include hallucinations, syncope, seizure, coma, respiratory arrest, and death. Symptomatic hyponatremia may require discontinuation of vilazodone, as well as implementation of the appropriate medical interventions.
Vitamin D analogs: (Moderate) Monitor serum calcium concentrations during concomitant use of thiazide diuretics and vitamin D analogs; a dosage adjustment of the vitamin D analog may be needed. Hypercalcemia may be exacerbated by concomitant administration.
Vitamin D: (Moderate) Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with thiazide diuretics. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia. Hypercalcemia may be exacerbated by coadministration of vitamin D or vitamin D analogs and thiazide diuretics. Thiazide diuretics are known to induce hypercalcemia by reducing the excretion of calcium in the urine.
Vitamin D: (Moderate) Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with thiazide diuretics. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia. Hypercalcemia may be exacerbated by coadministration of vitamin D or vitamin D analogs and thiazide diuretics. Thiazide diuretics are known to induce hypercalcemia by reducing the excretion of calcium in the urine.
Vorinostat: (Moderate) Use vorinostat and thiazide diuretics together with caution; the risk of QT prolongation and arrhythmias may be increased if electrolyte abnormalities occur. Thiazide diuretics may cause electrolyte imbalances including low potassium; hypomagnesemia, hypokalemia, or hypocalcemia may increase the risk of QT prolongation with vorinostat. Frequently monitor serum electrolytes if concomitant use of these drugs is necessary.
Vortioxetine: (Moderate) Patients receiving a diuretic during treatment with vortioxetine may be at greater risk of developing syndrome of inappropriate antidiuretic hormone secretion (SIADH). Clinically significant hyponatremia has been reported during therapy with vortioxetine. One case involving serum sodium levels lower than 110 mmol/l has occurred. Hyponatremia may be potentiated by agents which can cause sodium depletion such as diuretics. Discontinuation of vortioxetine should be considered in patients who develop symptomatic hyponatremia.
Ziconotide: (Moderate) Patients taking diuretics with ziconotide may be at higher risk of depressed levels of consciousness. If altered consciousness occurs, consideration of diuretic cessation is warranted in addition to ziconotide discontinuation.
Ziprasidone: (Moderate) Monitor potassium and magnesium levels when thiazide diuretics are used during ziprasidone therapy. The risk of QT prolongation from ziprasidone is increased in the presence of hypokalemia or hypomagnesemia.

How Supplied

Metolazone/Zaroxolyn Oral Tab: 2.5mg, 5mg, 10mg

Maximum Dosage
Adults

5 mg/day PO Zaroxolyn or generic equivalent for hypertension; 20 mg/day PO Zaroxolyn for edema; higher single doses such as 150 mg PO of Zaroxolyn have been used in the treatment of patients with chronic renal failure.

Elderly

5 mg/day PO Zaroxolyn for hypertension; 20 mg/day PO Zaroxolyn for edema; higher single doses such as 150 mg PO of Zaroxolyn have been used in the treatment of patients with chronic renal failure.

Adolescents

No maximum dosage information is available.

Children

0.4 mg/kg/day PO Zaroxolyn or generic equivalent.

Mechanism Of Action

Mechanism of Action: Metolazone has properties similar to the thiazide diuretics, acting to increase the excretion of sodium, chloride, and water by inhibiting sodium ion transport across the renal tubular epithelium. Metolazone exerts its effect primarily at the level of the cortical diluting segment of the nephron, although the increased excretion of phosphate and magnesium ions in patients with severely compromised renal function suggests proximal tubular activity as well. Thiazide diuretics decrease the glomerular filtration rate (GFR), contributing to the lower efficacy observed in patients with renal impairment. In contrast, metolazone does not decrease the GFR or the renal plasma flow, and is therefore able to produce diuresis in patients with a reduced GFR (i.e., less than 20 mL/min).
 
In clinical practice, metolazone is frequently used in combination with furosemide or other loop diuretics in patients who are refractory to diuresis with the loop diuretic alone. This combination often leads to marked diuresis. The increased delivery of sodium to the distal tubule accelerates potassium excretion via the sodium-potassium exchange mechanism, and hypochloremia and hypokalemia can occur, leading to mild metabolic alkalosis. Urinary calcium excretion is significantly decreased during long-term administration of thiazide therapy due to the decrease in extracellular fluid (ECF) volume and the slight increase in calcium reabsorption. Uric acid excretion is also decreased due to both the diuretic-induced decrease in ECF volume and the competitive inhibition of uric acid secretion.
 
Antihypertensive effects from diuretics initially are caused by hypovolemia, but after several weeks, other mechanisms are responsible. Plasma and ECF volumes eventually return to slightly less than normal, cardiac output returns to normal, and peripheral vascular resistance remains low. At this point, blood pressure is reduced by depletion of sodium within the smooth muscle cells of the arteriolar wall or loss of vascular autoregulatory feedback systems. Decreased plasma volume increases plasma renin activity, and aldosterone secretion is increased, contributing to the hypokalemia associated with thiazide diuretic therapy. In general, diuretics worsen glucose tolerance and exert detrimental effects on the lipid profile.

Pharmacokinetics

Metolazone is administered orally. Approximately 50—70% of circulating drug is bound to erythrocytes, and up to 33% is bound to plasma proteins. The drug crosses the placenta and is distributed into breast milk. A small portion of an oral dose is metabolized, while the majority (70%) of the drug is excreted unchanged in the urine by glomerular filtration and active tubular secretion. Clearance of the drug is proportional to creatinine clearance rates. The elimination half-life of metolazone has been reported to be roughly 14 hours.

Oral Route

Metolazone is available as an oral formulation with rapid and complete absorption (Mykrox) as well as an oral formulation with relatively slow and incomplete bioavailability (Zaroxolyn). Formulations bioequivalent to Mykrox and formulations bioequivalent to Zaroxolyn should not be substituted for one another. Metolazone is absorbed in varying degrees from the GI tract, depending on which formulation is used. Following oral administration of Mykrox, peak blood concentrations are attained within 2—4 hours. The Mykrox product formulation is no longer available in the US. After oral administration of Zaroxolyn, peak concentrations are observed about 8 hours after the dose. Healthy patients absorb approximately 65% of an oral dose of Zaroxolyn and other similar metolazone formulations, while patients with cardiac disease absorb about 40% of an oral dose.

Pregnancy And Lactation
Pregnancy

There are no adequate and well-controlled studies in pregnant women. Animal studies have revealed no evidence of harm due to metolazone; however, and animal reproduction studies are not always predictive of human fetal risk. Metolazone crosses the placental barrier and appears in cord blood. Diuretics are generally considered as second-line or third-line agents for the treatment of hypertension during pregnancy, due to the potential risk of intravascular volume depletion leading to fetal growth restriction or oligohydrosis; data do not indicate a positive benefit of diuretic use on the outcome of preeclampsia during pregnancy. The risk of diuretics may be increased in pregnant patients with reduced uteroplacental perfusion (e.g., preeclampsia or intrauterine growth retardation (IUGR)). There is a potential risk of neonatal or fetal thrombocytopenia, jaundice, or other adverse reactions that have been reported with adults with metolazone use during pregnancy. Potential risks from thiazide diuretic use include electrolyte imbalances in the newborn, pancreatitis, jaundice, or neonatal complications resulting from such maternal complications such as hyperglycemia, electrolyte imbalance, or hypotension. The effect of metolazone use during pregnancy on later growth, development, and functional maturation of the child is unknown.

According to the manufacturer, metolazone is excreted in breast milk, and because of the potential for serious adverse reactions in nursing infants from metolazone, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. Diuretics may reduce the quantity of breast milk. In previous American Academy of Pediatrics recommendations, thiazide diuretics, including bendroflumethiazide, chlorthalidone, chlorothiazide, and hydrochlorothiazide, were considered as usually compatible with breast-feeding. Of note, high doses of some thiazide diuretics have been used off-label to suppress lactation, and thus should be used with caution during the establishment of breast-feeding. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.