Carbonic Anhydrase Inhibitor Acetazoleamide (Diamox)

THE FOLLOWING study on the treatment of glaucoma with the carbonic anhydrase inhibitor acetazoleamide ( 2-acetylamino-1,3,4-thiadiazole-5-sulfonamide; Diamox) was initiated in October, 1953, and covers a four-month period of observation. Inhibition of carbonic anhydrase by acetazoleamide is a new and useful means of lowering the intraocular pressure. Acetazoleamide, a heterocyclic sulfonamide, was developed by Roblin and associates, in 1950,* as a diuretic agent whose action was based on inhibition of carbonic anhydrase in the renal tubular epithelium. Carbonic anhydrase catalyzes the hydration of carbon dioxide to form carbonic acid: H2O+CO2⇄ H2CO3. The carbonic acid dissociates to form H+and HCO3-. Thus, the level of hydrogen ions and bicarbonate ions is affected by this enzyme. In the kidney there ensues a hydrogen-sodium exchange between the tubular epithelium and the glomerular filtrate, resulting in the normal conservation of base and the formation of an acid urine.