The new diuretic agent, chlorothiazide (6-chloro-7-sulfamyl-1,2,4-benzot benzothiadiazine-1,1-dioxide),* is useful in the treatment of many clinical disorders, including congestive heart failure, cirrhosis, nephrosis, essential hypertension, premenstrual edema, and toxemia of pregnancy.1-9 Among its various clinical advantages are (1) remarkable effectiveness when administered orally; (2) prompt diuretic action, consisting of water diuresis, natruresis, and chloruresis but only minimal kaluresis; (3) persistent activity and lack of tolerance until edema subsides; (4) antihypertensive action, and (5) minimal side-effects or toxic reactions.
Basic pharmacologic studies have demonstrated that chlorothiazide inhibits carbonic anhydrase in vitro but not significantly in vivo,2 and clinical trials in man indicate that its diuretic action is qualitatively similar to that of the mercurial diuretics. In short-term animal experiments,1 maximal diuresis was observed at 40 minutes after intravenous administration, with a total duration of effect of about 4 hours. The peak response after oral administration occurred at 4 hours,