This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Degenerative Disorders, Subject name: Psychiatry
Drug used in alzheimer's disease are all EXCEPT: 
Select and explain. 
A. Biperidin, B. Donepezil, C. Rivastigmine, D. Memantine
A: Biperidin
Answer: A: Biperidin 
Explanation: Ans. (a) BiperidinRef.: Harrison 19th ed. / 2601-02Alzheimer's disease is most common cause of dementia.Drugs Used in the Treatment of Alzheimer's are:* Acetycholine esterase inhiitors:# Donepezil# Tacrine# Galantamine* Rivastigmine: Carbamate derivative of physostigmine* Memantine: NMDA glutaminergic antagonist* Biperidin is an anti cholinergic drug used to treat parkinsonism.