A sulfonamide derivative with diuretic, antiglaucoma, and anticonvulsant properties. Acetazolamide is a non-competitive inhibitor of carbonic anhydrase, an enzyme found in cells in the proximal tube of the kidney, the eye, and glial cells. Inhibition of this enzyme in the kidney prevents excretion of hydrogen, leading to increased bicarbonate and cation excretion and increased urinary volume, which results in an alkaline diuresis. Acetazolamide reduces the concentration of bicarbonate, resulting in a decreased synthesis of aqueous humor in the eye, thereby lowering intraocular pressure. Although its mechanism of action is unknown, acetazolamide has anti-convulsant properties resulting from indirect effects secondary to metabolic acidosis or direct effects on neuronal transmission. Acetazolamide also produces respiratory stimulant effects in response to changes to both carbon dioxide and oxygen tension levels within the lungs.

Carbonic anhydrase inhibitor that is sometimes effective against seizures.

One of the CARBONIC ANHYDRASE INHIBITORS that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. (From Smith and Reynard, Textbook of Pharmacology, 1991, p337)