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Hydrochlorothiazide / Triamterene
Class: Diuretic combination
- Tablets 37.5 mg triamterene/25 mg hydrochlorothiazide
- Capsules 37.5 mg triamterene/25 mg hydrochlorothiazide
- Tablets 75 mg triamterene/50 mg hydrochlorothiazide
Hydrochlorothiazide inhibits reabsorption of sodium and chloride in ascending loop of Henle and early distal tubules. Triamterene interferes with sodium reabsorption at distal tubule. Combination provides additive diuretic activity and antihypertensive effects and minimizes potassium depletion.
Indications and Usage
Treatment of edema or hypertension in patients who have or are at risk of developing hypokalemia.
Anuria; renal decompensation; severe hepatic disease; hypersensitivity to thiazides, triamterene, or sulfonamide-derived drugs; patients receiving spironolactone, amiloride, or potassium supplements; hyperkalemia; metabolic or respiratory acidosis.
Dosage and AdministrationAdults
PO 1 to 2 tablets or capsules daily.
Store in tightly closed container at room temperature.
Drug InteractionsAngiotensin-converting enzyme inhibitors
May result in severely elevated serum potassium levels.Allopurinol
May increase incidence of hypersensitivity reactions to allopurinol.Amantadine
May increase amantadine plasma levels and risk for adverse reactions.Anticoagulants
May diminish anticoagulant effects.Bile acid sequestrants
May reduce thiazide absorption; give thiazide at least 2 h before sequestrant.Diazoxide
May cause hyperglycemia.Digitalis glycosides
Diuretic-induced hypokalemia and hypomagnesemia may precipitate digitalis-induced arrhythmias.Indomethacin
May cause rapid progression into acute renal failure.Lithium
May decrease renal excretion of lithium; monitor lithium levels.Loop diuretics
May cause synergistic effects that may result in profound diuresis and serious electrolyte abnormalities.Methenamines, NSAIDs
May decrease effectiveness of thiazide.Potassium preparations
May severely increase serum potassium levels, possibly resulting in cardiac arrhythmias or cardiac arrest. Monitor serum potassium closely if potassium is coadministered.Sulfonylureas, insulin
May decrease hypoglycemic effect of sulfonylureas. May need to adjust dosage of sulfonylureas or insulin.
Laboratory Test Interactions
May interfere with the fluorescent measurement of quinidine serum levels. May decrease serum protein-bound iodine levels without signs of thyroid disturbance.
Dizziness; lightheadedness; vertigo; headache; paresthesias; weakness; restlessness; insomnia; fatigue.
Purpura; photosensitivity; rash; urticaria; necrotizing angiitis, vasculitis, cutaneous vasculitis; alopecia; exfoliative dermatitis; toxic epidermal necrolysis; erythema multiforme; Stevens-Johnson syndrome.
Blurred vision; xanthopsia (yellow vision).
Anorexia; gastric irritation; nausea; vomiting; abdominal pain or cramping; bloating; diarrhea; constipation; pancreatitis; sialadenitis; dry mouth.
Impotence; reduced libido; interstitial nephritis; azotemia; elevated BUN and creatinine.
Leukopenia; thrombocytopenia; agranulocytosis; aplastic or hypoplastic anemia; hemolytic anemia; megaloblastic anemia.
Jaundice; liver enzyme abnormalities.
Hyperglycemia; glycosuria; hyperuricemia; hyperkalemia; electrolyte imbalance; hypochloremia; hyponatremia.
Muscle cramp or spasm; fever; anaphylactic reactions.
Category C .
Excreted in breast milk.
Safety and efficacy have not been established.
May occur in patients with or without history of allergy or bronchial asthma; cross-sensitivity with sulfonamides may also occur.
May precipitate azotemia or hypermagnesemia; use drug with caution.
Minor alterations of fluid and electrolyte balance may precipitate hepatic coma; use drug with caution.
Electrolyte imbalances and BUN increase
Hyperkalemia (serum potassium greater than 5.5 mEq/L), hyponatremia, hypochloremia, and increases in BUN may occur.
Triamterene is a weak folic acid antagonist and may contribute to megaloblastosis.
May affect total serum cholesterol, total triglycerides, and LDL in some patients.
Antihypertensive effects may be enhanced.
Triamterene has been found in renal stones; use drug with caution in patients with histories of stone formation.
Orthostatic or general hypotension, tachycardia, syncope, electrolyte abnormalities, potassium deficiency, vomiting, nausea, shock, weakness, confusion, dizziness, cramps of calf muscles, thirst, polyuria, anuria, lethargy.
- Instruct patient to take medication early in day to avoid diuretic effect at night.
- Tell patient to take drug with food or milk and to report GI symptoms.
- Advise patient to limit sodium intake for optimal drug effect.
- Advise patient to limit exposure to sun and to use sunscreen or wear protective clothing to avoid photosensitivity reaction.
- Instruct diabetic patients to report increased levels of blood glucose.
- Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
- Tell patient to report these symptoms to health care provider: decrease in urinary output, jaundice, muscle cramps, weakness, nausea, blurred vision, dizziness.
- Instruct patient to drink 2 to 3 L/day of water unless contraindicated.
- Advise patient that drug may cause drowsiness and to use caution while driving or performing other tasks requiring mental alertness.
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