The effects of the carbonic anhydrase inhibitor 6063 on electrolytes and acid-base balance in two normal subjects and two patients with respiratory acidosis.

The effects of oral administration of sulfanilamide in man, on acid-base metabolism have been reported previously (1, 2). Sulfanilamide produces a transient increase in urine pH, CO2 content, sodium and potassium and a transient decrease in urinary ammonia. These urinary changes are associated with a fall in the serum CO2 content and a rise in serum chloride. The inhibition of the enzyme carbonic anhydrase by sulfanilamide was described by Mann and Keilin (3). It is believed that the effects of sulfanilamide on electrolyte and acid-base balance are due to the in-hibition of this enzyme in' the cells of the renal tubules (4). In 1949, Schwartz (5) reported the diuretic effect of sulfanilamide in three patients with congestive heart failure. However, the toxicity of this drug appeared to limit its possible usefulness as a diuretic agent. In 1950, Roblin and Clapp (6) described the preparation and properties of a series of heterocyclic sulfonamides. Their activity as potent inhibitors of the enzyme carbonic anhydrase in vitro was further investigated and amplified by Miller, Dessert and Roblin (7). The present study concerns some of the effects of one of these compounds "6063" (Diamox 3 2) (2 acetylamino-1,-3,4 thiadiazole-5-sulfonamide) on electrolyte and acidbase metabolism.