Rivastigmine:- This lipophilic relatively cere-broselective ChE inhibitor has been introduced for Alzheimer's disease (AD). Donepezil:- Another centrally acting anti-AChE that has produced cognitive and behavioral improvement in AD. It is long-acting and suitable for once daily administration. Galantamine:- This natural alkaloid inhibitor of cerebral AChE has in addition weak agonistic action on nicotinic receptors. It is being used to afford symptomatic relief in AD. Ref:- kd tripathi; pg num:-108