This class of drugs works by inhibiting cholinesterase, which is an enzyme that breaks down acetylcholine. Acetylcholine is a neurotransmitter in the brain that is involved in learning and memory. It is thought that decreased amounts of acetylcholine may contribute to Alzheimer's disease. By inhibiting cholinesterase, it will decrease the breakdown of acetylcholine and will increase the amount of acetylcholine in the brain.
Some side effects associated with this drug class include nausea, vomiting, diarrhea, dizziness, headache, fatigue, decreased appetite, and decreased weight. Cholinesterase inhibitors may interfere with the activity of anticholinergic medications (atropine, ipratropium, scopolamine). Succinylcholine and cholinergic agonists (acetylcholine, bethanechol, pilocarpine) produce additive effects when combined with cholinesterase inhibitors.
Aricept (donepezil) Tablets 5, 10, 23 mg
The usual starting dose of Aricept is 5 mg or 10 mg orally once daily for mild to moderate Alzheimer's disease and Aricept 10 mg or 23 mg for moderate to severe Alzheimer's disease. In the clinical trials, the efficacy of Aricept was measured by using cognitive subscale of the Alzheimer’s Disease Assessment Scale (ADAS-cog) which examines cognitive performance. The score range is 4 to 61 for the ADAS-cog test. In clinical trials, compared to placebo, Aricept 5 mg showed an improvement of 2.8 points and Aricept 10 mg had an improvement of 3.1 points on the ADAS-cog test.
Exelon (rivastigmine) Patches 4.6 mg, 9.5 mg patches
The usual starting dose is apply one Exelon 4.6 mg patch to the skin every 24 hours. After 4 weeks, it may be increased to one Exelon 9.5 mg patch every 24 hours. In clinical trials, compared to placebo, the improvement scores for the ADAS-cog test were 1.8 points for Exelon 9.5 mg patch and 2.9 points for Exelon 17.4 mg patch.
Razadyne (galantamine) Tablets 4, 8, 12 mg
Razadyne ER Tablets 8, 16, 24 mg
Razadyne Oral Solution 4 mg/ml
The usual dosing for Razadyne is 4 mg orally twice daily and may be increased by increments of 4 mg twice daily after 4 weeks of treatment. The usual dosing for Razadyne ER is 8 mg orally once daily in the morning and may be increased by increments of 8 mg daily after 4 weeks of treatment. In clinical trials, compared to placebo, the improvement scores for the ADAS-cog test were 1.7 points for Razadyne 8 mg, 3.3 points for Razadyne 16 mg, and 3.6 points for Razadyne 24 mg.
Cognex (tacrine) has been discontinued in the United States due to the risk of liver toxicity.
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