Which topical glaucoma medication primarily reduces aqueous humor production by inhibiting carbonic anhydrase, with caution in sulfa allergy?

• A. Latanoprost
• B. Dorzolamide
• C. Timolol
• D. Brimonidine

Answer: (B)

Reducing aqueous humor production by blocking carbonic anhydrase in the ciliary body lowers the fluid formed and thus lowers intraocular pressure. Dorzolamide is a topical carbonic anhydrase inhibitor, so it directly achieves this production reduction. The caveat about sulfa allergy exists because these drugs contain a sulfonamide group, which can be a concern for patients with sulfa sensitivities.

Other options work differently: one is a prostaglandin analog that increases outflow rather than decreasing production; another is a beta-blocker that lowers production by reducing ciliary body activity through adrenergic blockade; and another is an alpha-2 agonist that both reduces production and modestly increases outflow but is not a carbonic anhydrase inhibitor. Thus, dorzolamide uniquely fits the mechanism described.