Donepezil belongs to which drug class used in Alzheimer's disease?

• A. Acetylcholinesterase inhibitor
• B. NMDA receptor antagonist
• C. MAO inhibitor
• D. GABA agonist

Answer: (A)

Donepezil is an acetylcholinesterase inhibitor. It works by blocking the enzyme that breaks down acetylcholine in the brain, increasing acetylcholine in the synaptic cleft. This helps boost cholinergic signaling, which can modestly improve or stabilize cognitive symptoms in some patients with Alzheimer’s disease, reflecting the loss of cholinergic neurons in the condition. This class—acetylcholinesterase inhibitors—is a common symptomatic treatment for mild to moderate Alzheimer’s.

Other approaches used in Alzheimer's operate by different mechanisms. For example, memantine is an NMDA receptor antagonist that aims to reduce excitotoxic nerve damage in more advanced disease, not by increasing acetylcholine. Monoamine oxidase inhibitors aren’t standard treatments for Alzheimer’s, and GABA agonists are not used to treat the core cognitive symptoms of this condition.