Cosopt is a combination drop containing dorzolamide with which other agent?

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

Answer: (A)

Cosopt pairs two mechanisms to lower eye pressure by reducing aqueous humor production. Dorzolamide is a carbonic anhydrase inhibitor in the ciliary body, which lowers fluid formation. Timolol is a nonselective beta-blocker that also reduces aqueous production by blocking ciliary body beta receptors. Using them together gives an additive effect, lowering intraocular pressure more than either alone.

The other drugs listed belong to different classes that don’t form this fixed combination with dorzolamide: brimonidine is an alpha-2 agonist, latanoprost is a prostaglandin analog that increases outflow, and pilocarpine is a muscarinic agonist that also affects outflow. That’s why the correct pairing with dorzolamide in Cosopt is timolol.