The New Cholinesterase Inhibitors for Alzheimer's Disease, Part 1: Their Similarities Are Different

Article Abstract

Contemporary treatment of the memory disturbance in Alzheimer’s disease is to boost declining cholinergic function, which is characteristic of this disease. The best way to do this so far is to stop the breakdown of acetylcholine (ACh) by inhibiting the enzyme acetylcholinesterase (AChE). The first available agent to stop the breakdown, tacrine (Cognex), was limited by its short duration of action, narrow dosing range, drug interactions, and liver toxicity. Donepezil (Aricept), rivastigmine (Exelon), and galantamine (Reminyl) all remove these unfavorable actions. They also inhibit AChE. Are these 3 drugs therefore all the same? In considering the answer, let’s think of baseball great Yogi Berra’s response to a question about whether he and his son were alike: "Our similarities are different." All 3 cholinesterase inhibitors are similar in that they inhibit AChE, yet they are also different in terms of other pharmacologic properties. These distinctions may help prescribers decide how to select one agent over another for different Alzheimer patients.