indication

For treatment of chronic open-angle glaucoma and acute angle-closure glaucoma

pharmacology

Methazolamide is topical carbonic anhydrase inhibitor. Methazolamide is indicated for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers. Methazolamide is a sulfonamide derivative; however, it does not have any clinically significant antimicrobial properties. Although methazolamide achieves a high concentration in the cerebrospinal fluid, it is not-considered an effective anticonvulsant. Methazolamide has a weak and transient diuretic effect, therefore use results in an increase in urinary volume, with excretion of sodium, potassium and chloride.

mechanism of action

Methazolamide is a potent inhibitor of carbonic anhydrase. Inhibition of carbonic anhydrase in the ciliary processes of the eye decreases aqueous humor secretion, presumably by slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport.

toxicity

Electrolyte imbalance, development of an acidotic state, and central nervous system effects might be expected to occur in the case of an overdose.

absorption

Methazolamide is well absorbed from the gastrointestinal tract.

half life

14 hours

drug interactions

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

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

Brinzolamide: As both brinzolamide and methazolamide 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.

Magnesium salicylate: The salicylate, magnesium salicylate, at high dose increases the effect of the carbonic anhydrase inhibitor, methazolamide.

Memantine: Possible increased levels of memantine

Salicylate-sodium: The salicylate, salicylate-sodium, at high dose increases the effect of the carbonic anhydrase inhibitor, methazolamide.

Salsalate: The salicylate, salsalate, at high dose increases the effect of the carbonic anhydrase inhibitor, methazolamide.

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

Trisalicylate-choline: The salicylate, trisalicylate-choline, at high dose increases the effect of the carbonic anhydrase inhibitor, methazolamide.