memantine

noun

mem·​an·​tine ˈmem-an-ˌtēn 

: a drug that blocks the action of glutamate and is taken orally in the form of its hydrochloride C₁₂H₂₁N·HCl in the treatment of moderate to severe Alzheimer's disease

Note: Memantine is marketed under the trademark Namenda and when used in combination with donepezil, under the trademark Namzaric.