Donepezil (a cholinesterase inhibitor used for Alzheimer’s disease) is listed as capable of decreasing intraocular pressure. Which option is correct?

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

Answer: (C)

Donepezil lowers intraocular pressure by increasing acetylcholine in the eye. By inhibiting acetylcholinesterase, it boosts parasympathetic activity, and the extra acetylcholine stimulates muscarinic receptors on the ciliary muscle. This causes the ciliary muscle to contract, opening the trabecular meshwork and enhancing aqueous humor outflow, which reduces IOP. The other drugs listed lower IOP through their own glaucoma-specific mechanisms (prostaglandin-mediated outflow, alpha-adrenergic–mediated outflow plus reduced production, or beta-blocker–mediated production reduction), but the question highlights donepezil as the agent capable of decreasing IOP through cholinergic stimulation.