indication

For adjunctive treatment of: edema due to congestive heart failure; drug-induced edema; centrencephalic epilepsies; chronic simple (open-angle) glaucoma

pharmacology

Acetazolamide is a potent carbonic anhydrase inhibitor, effective in the control of fluid secretion, in the treatment of certain convulsive disorders and in the promotion of diuresis in instances of abnormal fluid retention. Acetazolamide is not a mercurial diuretic. Rather, it is a nonbacteriostatic sulfonamide possessing a chemical structure and pharmacological activity distinctly different from the bacteriostatic sulfonamides.

mechanism of action

The anticonvulsant activity of Acetazolamide may depend on a direct inhibition of carbonic anhydrase in the CNS, which decreases carbon dioxide tension in the pulmonary alveoli, thus increasing arterial oxygen tension. The diuretic effect depends on the inhibition of carbonic anhydrase, causing a reduction in the availability of hydrogen ions for active transport in the renal tubule lumen. This leads to alkaline urine and an increase in the excretion of bicarbonate, sodium, potassium, and water.

half life

3 to 9 hours

drug interactions

Acetylsalicylic acid: Acetylsalicylic acid at high dose increases the effect of the carbonic anhydrase inhibitor, acetazolamide.

Bismuth Subsalicylate: The salicylate, bismuth subsalicylate, at high dose increases the effect of the carbonic anhydrase inhibitor, acetazolamide.

Brinzolamide: As both brinzolamide and acetazolamide are carbonic anhydrase inhibitors, there is an increased risk of adverse effects.The development of acid-base disorders with concurrent use of ophthalmic and oral carbonic anhydrase inhibitors has been reported. Avoid concurrent use of different carbonic anhydrase inhibitors when possible.

Cyclosporine: Acetazolamide may increase the effect and toxicity of cyclosporine.

Memantine: Possible increased levels of memantine

Tobramycin: Increased risk of nephrotoxicity

Topiramate: Additive renal carbonic anhydrase inhibition may occur increasing the risk of crystaluria and renal calculi. Increased risk of nephrolithiasis. Consider altnerate therapy.

Treprostinil: Additive hypotensive effect. Monitor antihypertensive therapy during concomitant use.

Triprolidine: The CNS depressants, Triprolidine and Acetazolamide, may increase adverse/toxic effects due to additivity. Monitor for increased CNS depressant effects during concomitant therapy.