Evaluation of memantine for the treatment of Alzheimer's disease.

Increasing evidence suggests that disturbances in glutamatergic activity play an important role in Alzheimer's disease (AD). Excessive glutamate-mediated activation of NMDA receptors, for example, may contribute to the neuronal death that characterises AD. On the other hand, physiological activation of the NMDA receptor appears necessary for normal cognitive function. Therefore, compounds that finely modulate NMDA receptor activity hold promise as treatments for AD. Memantine (Namenda, Axura, Ebixa; Forest Laboratories, Inc., Merz Pharmaceuticals GmbH, H. Lundbeck A/S) is a low-moderate affinity, uncompetitive NMDA-receptor antagonist that appears to block pathological, but not physiological, activation of the NMDA receptor. Consequently, therapeutic doses of the drug are well-tolerated and do not seem to interfere with the acquisition or processing of cognitive information. Memantine has been shown to improve symptoms and reduce the rate of clinical deterioration among patients with moderate-to-severe AD and was approved in the US for this indication in October 2003. This review provides a brief rationale for the development of memantine as a therapy for AD, as well as an overview of the pharmacology, clinical efficacy, safety and tolerability of this novel therapeutic agent.