These "cholinesterase inhibitors" include tacrine (Cognex), donepezil (Aricept), rivastigmine (Exelon) and galantamine (Razadyne, formerly called Reminyl).

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One drug which does this, Cognex (made by Warner-Lambert), has been on the market since 1994.

ECONOMIST: Disposing of dementia | The

It does not cause adverse liver reactions and also seems more effective than Cognex.

ECONOMIST: Disposing of dementia | The