DIURETIC ACTION OF TWO CARBONIC ANHYDRASE INHIBITORS IN CONGESTIVE FAILURE

Two carbonic anhydrase inhibitors, acetazolamide and ethoxzolamide, were compared with intramuscularly given meralluride by oral administration in a group of ambulatory patients with congestive heart failure, with the criterion of response being the loss of body weight during the first 24 hours after the dose. The maximum diuretic response to acetazolamide was equal approximately to that given by 0.5 cc. of meralluride; the response to ethoxzolamide was somewhat greater, equal approximately to that given by 0.7 cc. of meralluride. The diuretic responses to the two carbonic anhydrase inhibitors were similar when they were given in doses which caused approximately the same incidence of unpleasant symptoms. The maximum diuretic effect of acetazolamide was obtained from a dose of 125 mg. No greater effect was obtained from a dose eight times larger. It was found that orally given acetazolamide neither increases nor diminishes the diuretic response to intramuscularly given meralluride.