American Board of Psychiatry and Neurology (ABPN) Practice Exam 2026 - Free ABPN Practice Questions and Study Guide

Memantine is an NMDA receptor antagonist that is particularly significant in the treatment of moderate to severe Alzheimer's disease. Its mechanism of action focuses on blocking excessive glutamate activity at the NMDA receptors, which are involved in learning and memory processes. By doing so, memantine helps protect neurons from excitotoxicity, which can occur from overstimulation by glutamate. This property distinguishes it from cholinesterase inhibitors, which work to increase levels of acetylcholine in the brain by inhibiting the enzyme that breaks it down.

Cholinesterase inhibitors, such as donepezil, galantamine, and rivastigmine, function through a different mechanism by enhancing cholinergic transmission. These medications are primarily aimed at improving cognitive symptoms associated with Alzheimer's disease by increasing the availability of acetylcholine, not by modulating glutamatergic activity. Therefore, memantine stands out in this context as it specifically targets NMDA receptors, providing a unique therapeutic approach in Alzheimer's treatment that is separate from cholinergic enhancement.