NMDA antagonist used in Alzheimer's disease is:

Ans: A (Memantine) Ref: Goodman and Gilman's "Phannacologica! Basis of Therapeutics'' 12th eci p.622Explanation:Memantine* It is used either as an adjunct or an alternative to cholinesterase inhibitors in Alzheimer's disease, and is also commonly used to treat other neurodegenerative dementias,Memantine is a noncompetitive antagonist of the NMDA-type glutamate receptor.It interacts with the Mg2+ binding site of the channel to prevent excessive activation while sparing normal function.Adverse effects of memantine include headache or dizziness, hut are usually mild and reversible.The drug is excreted by the kidneys and dosage should be reduced in patients with severe renal impairment.