Class: Thiazide diuretic
- Tablets 1.25 mg
- Tablets 2.5 mg
Enhances excretion of sodium, chloride, and water by interfering with transport of sodium ions across renal tubular epithelium.
C max is approximately 115 to 260 ng/mL (dose-dependent). The T max is 2 h.
71% to 79% is protein bound.
The t ½ is 26 h. More than 70% is excreted in the urine, and 23% is excreted in the GI tract, probably including the biliary route.
Indications and Usage
Treatment of edema associated with CHF, hepatic cirrhosis, renal dysfunction, and corticosteroid or estrogen therapy; management of hypertension.
Treatment of calcium nephrolithiasis, osteoporosis, or diabetes insipidus.
Hypersensitivity to thiazides, related diuretics, or sulfonamide-derived drugs; anuria.
Dosage and AdministrationAdults
PO 1.25 to 5 mg every morning. Maximum 5 mg/day.
- Administer as morning dose to prevent nocturia.
- Give with food or milk if GI upset occurs.
- Store in tightly closed container at room temperature.
Drug InteractionsBile acid sequestrants
May reduce thiazide absorption; give thiazide at least 2 h before resin.Diazoxide
Hyperglycemia may occur.Digitalis glycosides
Diuretic-induced hypokalemia and hypomagnesemia may precipitate digitalis-induced arrhythmias.Lithium
May decrease renal excretion of lithium; monitor lithium levels.Loop diuretics
May result in synergistic effects and result in profound diuresis and serious electrolyte abnormalities.Sulfonylureas, insulin
May decrease hypoglycemic effect of sulfonylureas. May need to adjust dosage of sulfonylureas or insulin.
Laboratory Test Interactions
May decrease serum protein-bound iodine levels without signs of thyroid disturbance. May cause diagnostic interference of serum electrolyte levels, blood and urine glucose levels, serum bilirubin levels and serum uric acid levels. May increase serum magnesium levels in uremic patients.
Orthostatic hypotension; palpitations.
Dizziness; lightheadedness; vertigo; headache; weakness; restlessness; insomnia; drowsiness; fatigue; lethargy; anxiety; depression; nervousness.
Rash; necrotizing angiitis; vasculitis; cutaneous vasculitis; pruritus.
Anorexia; gastric irritation; epigastric distress; nausea; vomiting; abdominal pain/cramping/bloating; diarrhea; constipation; dry mouth.
Nocturia; impotence/reduced libido.
Hyperglycemia; glycosuria; hyperuricemia.
Muscle cramp or spasm; acute gout.
Category B .
May be excreted in breast milk.
May occur in patients with or without history of allergy or bronchial asthma; cross-sensitivity with sulfonamides may also occur.
May precipitate azotemia; use with caution.
Minor alterations of fluid and electrolyte balance may precipitate hepatic coma; use with caution.
Severe hyponatremia and hypokalemia may infrequently occur with recommended doses; more common in elderly females.
May cause increased concentrations of total triglycerides and LDL in some patients.
Exacerbation or activation may occur.
Antihypertensive effects may be enhanced.
Orthostatic or general hypotension, syncope, electrolyte abnormalities, potassium deficiency, vomiting, respiratory depression, lethargy, shock, weakness, confusion, dizziness, cramps of calf muscles, thirst, polyuria, anuria.
- Tell patient to take medication early in day to prevent sleep problems.
- Instruct patient to take drug with food or milk to minimize GI irritation.
- Caution patient to avoid exposure to sunlight and to use sunscreen or wear protective clothing to avoid photosensitivity reaction.
- Instruct patients with diabetes to report increased blood glucose levels.
- Caution patients to avoid sudden position changes to prevent orthostatic hypotension.
- Advise patients to include in diet foods that are high in potassium (eg, bananas, broccoli, dried fruits, grapefruit, lima beans, nuts, oranges).
- Tell patient to report decrease in urinary output, jaundice, muscle cramps, weakness, nausea, blurred vision, or dizziness.
- For patients being treated for hypertension, explain benefits of weight reduction, exercise, reduction of alcohol and sodium intake, cessation of smoking.
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