About memantinen-methyl-d-aspartate receptor antagonist, dopamine d2 agonist, antidementia agent,in alzheimer`s disease.mechanism of action of memantinememantine in an uncompetitive (low to moderate affinity to) nmda (n-methyl-d-aspartate) receptor antagonist. it regulates the activity of glutamate which is involved in information processing, storage and retrieval. excess glutamate plays a role in neuronal cell death and it is common to all neurodegenerative diseases. in alzheimer`s disease excess release of glutamate occurs. sustained elevation of glutamate over stimulates nmda receptors and allows too much of calcium in to nerve cells and leads to cell degeneration and cell death. memantine prevents these actions by inhibiting the binding of glutamate at nmda receptor.