Chlorthalidone is a diuretic agent of value used in the treatment of edema, hypertension, and congestive heart failure. The drug is notable for its prolonged action (between 48 and 72 hours), and low toxicity. Chlorthalidone differs from other sulfonamide diuretics in that a double-ring system is incorporated into its chemical structure. It is administered orally. Until the 1980s, it had formerly been sold under the brand name of Hygrotone.
Actions: The diuretic action of chlorthalidone is thought to be due to inhibition of sodium and chloride reabsorption in the proximal tubule. The initial antihypertensive action of the drug is due to a reduction of plasma volume following diuresis.
Warnings: It should be used with care during pregnancy.