What is the MOA of acetazolamide?

Acetazolamide's mechanism of action centers on its function as a carbonic anhydrase inhibitor. Carbonic anhydrase is an enzyme that facilitates the reversible conversion of carbon dioxide and water into bicarbonate and protons. By inhibiting this enzyme, acetazolamide reduces the rehydration of carbon dioxide, leading to decreased bicarbonate formation. This action alters the acid-base balance and enhances renal excretion of bicarbonate, which results in metabolic acidosis.

This unique mechanism is important for its therapeutic applications, particularly in conditions such as glaucoma, where reducing intraocular pressure is beneficial, and in altitude sickness, where it helps offset respiratory alkalosis. The inhibition of carbonic anhydrase also has implications in various clinical treatments including chronic obstructive pulmonary disease (COPD) and for enhancing renal excretion of certain drugs.

In contrast to the other options presented, which involve different pharmacological mechanisms, carbonic anhydrase inhibition is specifically what defines acetazolamide's role and therapeutic effects.