Trade Names:Hydrochlorothiazide- Tablets 12.5 mg- Tablets 25 mg- Tablets 50 mg
Trade Names:Microzide- Capsules 12.5 mgApo-Hydro (Canada)PMS-Hydrochlorothiazide (Canada)
Enhances excretion of sodium, chloride, and water by interfering with transport of sodium ions across renal tubular epithelium.
Bioavailability is 65% to 75%, C max is 70 to 490 ng/mL (dose dependent), and T max is 1 to 5 h. Food reduces the bioavailability 10% and the C max 20%; increases the T max from 1.6 to 2.9 h. Plasma concentrations are linearly related to administration doses.
Protein binding is 40% to 68% and crosses the placenta, but not the blood brain barrier. It is also excreted in breast milk.
Hydrochlorothiazide is not metabolized.
Hydrochlorothiazide is eliminated primarily by renal pathways (as unchanged by the kidneys; 55% to 77% or the administration dose appear in urine with more than 95% of the absorbed dose excreted in urine unchanged). Plasma t ½ is 5.6 to 14.8 h.
The time to peak effect is about 4 h.
Hydrochlorothiazide activity may persist for up to 24 h.
Hydrochlorothiazide plasma concentration is increased and the t ½ is prolonged.
Adjunctive therapy for edema associated with CHF, hepatic cirrhosis, renal function impairment, and corticosteroid and estrogen therapy; treatment of hypertension.
Prevention of formation and precurrence of calcium nephrolithiasis; therapy for nephrogenic diabetes insipidus.
Hypersensitivity to thiazides, related diuretics, or sulfonamide-derived drugs; anuria; renal decompensation.
PO 25 to 100 mg/day. Rarely patients may require 200 mg/day.HypertensionAdults
PO 25 to 50 mg/day as single dose or 2 divided doses.Children (2 to 12 yr of age)
PO 37.5 to 100 mg/day in 2 doses.Infants (6 mo to 2 yr of age)
PO 12.5 to 37.5 mg/day in 2 doses.Infants (younger than 6 mo)
PO Up to 3.3 mg/kg/day in 2 doses.
Store tablets in tightly closed container at room temperature.
May reduce thiazide absorption; give thiazide at least 2 h before resin.Diazoxide
May cause hyperglycemia.Digitalis glycosides
Diuretic-induced hypokalemia and hypomagnesemia may precipitate digitalis-induced arrhythmias.Lithium
May decrease renal excretion of lithium.Loop diuretics
Synergistic effects may result in profound diuresis and serious electrolyte abnormalities.Sulfonylureas, insulin
May decrease hypoglycemic effect of sulfonylureas. May need to increase dosage of sulfonylureas or insulin.
Drug 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. Drug may increase serum magnesium levels in uremic patients. Drug may cause increased concentrations of total serum cholesterol, total triglycerides, and LDL.
Dizziness; lightheadedness; vertigo; headache; paresthesias; weakness; restlessness; insomnia.
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.
Impotence; reduced libido; interstitial nephritis.
Leukopenia; thrombocytopenia; agranulocytosis; aplastic or hypoplastic anemia; hemolytic anemia.
Hyperglycemia; glycosuria; hyperuricemia; electrolyte imbalance.
Respiratory distress; pneumonitis; pulmonary edema.
Muscle cramp or spasm; fever; anaphylactic reactions.
Category B .
Excreted in breast milk.
Safety and efficacy have not been established in controlled clinical studies.
May occur in patients with or without history of allergy or bronchial asthma; cross-sensitivity with sulfonamides may also occur.
Drug may precipitate azotemia; use drug with caution.
Minor alterations of fluid and electrolyte balance may precipitate hepatic coma; use drug with caution.
Exacerbation or activation may occur.
Drug may enhance antihypertensive effects.
Orthostatic or general hypotension, tachycardia, shock, weakness, syncope, confusion, dizziness, electrolyte abnormalities, potassium deficiency, vomiting, nausea, lethargy, cramps of calf muscles, thirst, polyuria, anuria.
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