Chlorothiazide - Chlorothiazide is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention.
Chlorothiazide treats fluid retention (edema) in people with congestive heart failure, cirrhosis of the liver, or kidney disorders, or edema caused by taking steroids or estrogen. This medication is also used to treat high blood pressure (hypertension).
Chlorothiazide may also be used for other purposes not listed in this medication guide.
Pharmacology: Enhances excretion of sodium, chloride, and water by interfering with transport of sodium ions across renal tubular epithelium.
Indication: Adjunctive treatment in edema associated with CHF, hepatic cirrhosis, and corticosteroid and estrogen therapy; edema caused by various forms of renal function impairment such as nephrotic syndrome, acute glomerulonephritis, and chronic renal failure (oral and IV); management of hypertension (oral).
Calcium nephrolithiasis; diabetes insipidus; osteoporosis.
Like other thiazides, Chlorothiazide promotes water loss from the body (diuretics). It inhibits Na reabsorption from the distal convoluted tubules in the kidneys. Thiazides also cause loss of potassium and an increase in serum uric acid. Thiazides are often used to treat hypertension, but their hypotensive effects are not necessarily due to their diuretic activity. Thiazides have been shown to prevent hypertension-related morbidity and mortality although the mechanism is not fully understood. Thiazides cause vasodilation by activating calcium-activated potassium channels (large conductance) in vascular smooth muscles and inhibiting various carbonic anhydrases in vascular tissue. Chlorothiazide affects the distal renal tubular mechanism of electrolyte reabsorption. At maximal therapeutic dosages, all thiazides are approximately equal in their diuretic efficacy. Chlorothiazide increases excretion of sodium and chloride in approximately equivalent amounts. Natriuresis may be accompanied by some loss of potassium and bicarbonate. After oral doses, 10-15 percent of the dose is excreted unchanged in the urine. Chlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk.
Adult: PO HTN 250-500 mg/day, up to 1 g/day. Oedema 0.25-1 g 1-2 times/day. Max: 2 g/day.
Adult: 250-500 mg daily as single or divided dose. Up to 1 g daily. May be given via IV admin using the sodium salt.
Child: Up to 25 mg/kg daily in 2 divided doses. Infants up to 6 mth: Up to 35 mg/kg daily in 2 divided doses. Oral Oedema
Adult: 0.25-1 g once daily or bid, may also be taken on alternate days or on 3-5 days wkly. Max: 2 g/day. May be given via IV admin using the sodium salt.