Why is this medication prescribed?
Chlorothiazide is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention.
This medicine treats fluid retention (edema) in people with congestive heart failure, cirrhosis of the liver, kidney disorders, or edema caused by taking steroids or estrogen. This medication is also used to treat high blood pressure (hypertension).
Mechanism of Action:
Thiazide diuretics increase the excretion of water by inhibiting the reabsorption of sodium and chloride ions at the distal renal tubule. The natriuretic effects are accompanied by a secondary loss of potassium and bicarbonate which can cause a mild hypokalemic, hypochloremic, metabolic alkalosis. Thiazides also decrease the elimination of calcium and uric acid. Thiazides diuretics usually do not affect normal blood pressure. When chronically administered, diuretics decrease peripheral vascular resistance. The exact mechanism responsible for the lowered peripheral resistance is not known, however, excretion of urinary sodium by the kidneys is required to achieve blood pressure reduction.
Initially, diuretics lower blood pressure by decreasing cardiac output, plasma volume and extracellular fluid volume. Cardiac output eventually returns to normal, plasma and extracellular fluid values return to slightly less than normal, but peripheral vascular resistance is reduced, resulting in lower blood pressure. Thiazide diuretics also decrease the glomerular filtration rate, which contributes to the drug's lower efficacy in patients with renal impairment. The changes in plasma volume induce an elevation in plasma renin activity and aldosterone secretion which contributes to the potassium losses associated with thiazide diuretics. In general, diuretics can worsen LVH, glucose tolerance, and lipid abnormalities.
Dosage and using this medicine
What special precautions should I follow?
What should I do if I forget a dose?
What side effects can this medication cause?