Which carbonic anhydrase inhibitor lowers aqueous production?

• A. Dorzolamide
• B. Brinzolamide
• C. Acetazolamide
• D. Methazolamide

Answer: (A)

Carbonic anhydrase inhibitors reduce aqueous humor production by blocking the enzyme in the ciliary epithelium. This decreases the formation of bicarbonate, which lowers the osmotic gradient driving water into the posterior chamber, resulting in less aqueous humor being produced and a drop in intraocular pressure.

Dorzolamide is a topical carbonic anhydrase inhibitor that acts directly at the site of aqueous production in the ciliary body, producing a focused and rapid reduction in aqueous formation with minimal systemic effects. Brinzolamide works similarly as another topical option, but dorzolamide is the representative agent highlighted for decreasing aqueous production. Systemic inhibitors like acetazolamide and methazolamide also reduce production but come with more systemic side effects, making topical agents typically preferred for this purpose.