Students: This article is meant to be a general overview and is not a primary source. Go to the bibliography (and other literature) for primary sources.

Alzheimer's Medications (Part 1), the Cholinesterase Inhibitors

by Becky Sisk, PhD, RN

Š Revised 2004

There is no cure for Alzheimer's disease. However, several medications alleviate early cognitive symptoms.

Recall that the basic problem in Alzheimer's disease is structural damage to brain cells, resulting in amyloid plaques and neurofibrillary tangles. Amyloid plaques are deposits of a substance called beta-amyloid, which are toxic to neurons. Neurofibrillary tangles are made up of a substance called tau. Tau exists normally in brain cells, but, in Alzheimer's disease, it forms abnormal, twisted threads--the neurofibrillary tangles--that interfere with the neuron's ability to transport messages.

Acetylcholine, a neurotransmitter that facilitates the activity from one neuron to the next, is markedly decreased in Alzheimer's disease. Cholinesterase, an enzyme, normally breaks down acetylcholine. The drugs currently approved by the FDA for Alzheimer's disease are "cholinesterase inhibitors," which slow this breakdown process.

The FDA-approved drugs for Alzheimer's disease are tacrine (Cognex), donepezil (Aricept), rivastigmine (Exelon), and galantamine (Reminyl). These drugs are given to people in the early stages of Alzheimer's disease and are not curative. They slow the memory and cognitive impairments characteristic of Alzheimer's disease. Usual doses are as follows:

Medication	Dose	Precautions*
Donepezil (Aricept)	5-10 mg. orally per day, usually given at bedtime	May interact with cimetidine (Tagamet), digoxin (Lanoxin), and theophylline
Rivastigmine (Exelon)	Increased over several weeks from 1.5 mg to eventual dose of 6-12 mg orally per day	May cause weight loss May interact with aminoglycosides or procainamide (Procanbid)
Galantamine (Reminyl)	Gradually increased from 8 mg. orally to 16 mg. orally per day	Contraindicated if patient has kidney or liver problems
Tacrine (Cognex)	10 mg. orally, four times per day, Gradually increased over several weeks to 40 mg four times per day, as tolerated	May interact with procainamide or theophyline May cause liver damage No longer considered a drug of choice for Alxzheimer's disease (Cummings et al., 2002)

*Side effects of these drugs include anorexia, nausea, vomiting, and diarrhea. In addition to cholinesterase inhibitors, antioxidants, such as vitamin E, are given to remove free radicals, metabolic byproducts that appear to cause cell damage in the aging process.

Reference:

Cummings, J.L., Drank, K.C., Cherry, D., Kohatsu, N.D., Kemp, B., Hewett, L. & Mittman, B. (2002). Guidelines for managing Alzheimer's disease. American Family Physician, 65(12):

The latest books on Alzheimer's care are available at Amazon.com:

This article was revised from an article in Volume 1, #2 of the "Clinical Nursing Resources" newsletter. To subscribe, send a blank email to: mailto:nursescribe-subscribe@topica.com

PDAs & Software