Carbonic Anhydrase Inhibitor - Types

Types

Acetazolamide is an inhibitor of carbonic anhydrase. It is used for glaucoma, epilepsy (rarely), idiopathic intracranial hypertension, and altitude sickness. It can act as a mild diuretic by reducing NaCl and bicarbonate reabsorption in the proximal tubule. However, the distal segment partially compensates for the sodium loss, and the bicarbonaturia will produce a metabolic acidosis, further reducing the effect.

Methazolamide is also a carbonic anhydrase inhibitor. It has a longer elimination half-life than acetazolamide and is less associated with adverse effects to the kidney.

Dorzolamide is a sulfonamide) and topical carbonic anhydrase II inhibitor. It is indicated for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension and who are insufficiently responsive to beta-blockers. Inhibition of carbonic anhydrase II 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.

Topiramate is a weak inhibitor of carbonic anhydrase, particularly subtypes II and IV. It is a sulfamate-substituted monosaccharide, related to fructose. In the US, it is approved by the U.S. Food and Drug Administration (FDA) as an anticonvulsant to treat epilepsy and Lennox-Gastaut syndrome, and also to treat migraine headaches. In rare cases, the inhibition of carbonic anhydrase may be strong enough to cause metabolic acidosis of clinical importance.

Ellagitannins extracted from the pericarps of Punica granatum, the pomegranate, such as punicalin, punicalagin, granatin B, gallagyldilactone, casuarinin, pedunculagin and tellimagrandin I, are highly active carbonic anhydrase inhibitors.