 Memantine Namenda is a low-affinity N-methyl-D-aspartate NMDA receptor antagonist believed to work by blocking prolonged low-level activation of the NMDA receptor and resultant neuronal damage caused by abnormal glutamatergic activity, yet also allowing normal physiological activity of the NMDA channel. Memantine Namenda was approved by the U.S. Food and Drug Administration in 2003 for the treatment of moderate to severe Alzheimers disease. Memantine improves or delays the decline in cognition attention, language, visuo-spatial ability, as well as functional and behavioral symptoms in adults with moderate Alzheimers disease. 