Cholinesterase Inhibitors in Alzheimer's Disease

Introduction to Cholinesterase Inhibitors

The American College of Physicians suggests that cholinesterase inhibitors, such as donepezil, galantamine, and rivastigmine, are effective first-line treatments for mild to moderate Alzheimer's disease, producing statistically significant but modest improvements in cognition and global function 1

Cholinesterase inhibitors improve cognition by approximately 2.7 points on the 70-point ADAS-Cog scale compared to placebo, representing a statistically significant but clinically modest effect 2, 3
Approximately 20-35% of patients show a 7-point improvement on neuropsychological tests, equivalent to reversing one year's cognitive decline 1
Clinicians rated global clinical state more positively in treated patients, with a relative risk of improvement of 2.01 on the CIBIC-plus scale 3, 4

The American Academy of Neurology recommends starting with donepezil 5 mg once daily in the evening for mild to moderate Alzheimer's disease, and increasing to 10 mg daily after 4-6 weeks if tolerated 1, 5
For moderate to severe Alzheimer's disease, the American Geriatrics Society suggests initiating donepezil first using the same dosing schedule as above, and adding memantine after establishing donepezil therapy 1, 6

Gastrointestinal effects, such as nausea, vomiting, and diarrhea, are the most common adverse events, occurring more frequently than with placebo 2, 7
Initial agitation may occur but typically subsides after the first few weeks 1

The American Medical Association recommends considering discontinuation if clinically meaningful worsening occurs over 6 months without other contributing factors, or if no clinical benefit is observed during treatment 6, 5
Treatment effects do not prevent disease progression, and the illness continues to advance even during treatment 2, 7

The American Academy of Family Physicians recommends the use of cholinesterase inhibitors, including donepezil, rivastigmine, galantamine, and tacrine, for the treatment of Alzheimer's disease 8, 9

Donepezil has a half-life of 70-80 hours and is not hepatotoxic, with no liver monitoring required 8
Rivastigmine is dosed twice daily, with a maximum dose of 6-12 mg/day, and its absorption is reduced by food 8
Galantamine is dosed twice daily with meals, with a starting dose of 4 mg twice daily and an increase to 8 mg twice daily after 4 weeks 8
Tacrine is rarely prescribed due to its hepatotoxicity and frequent dosing, with a dosing schedule of four times daily 8

The American Academy of Family Physicians notes that there is no head-to-head superiority among cholinesterase inhibitors, with the main differences being tolerability and dosing convenience 8
Approximately 20-35% of patients show a 7-point improvement on neuropsychological tests, equivalent to reversing one year's cognitive decline, with donepezil, rivastigmine, or galantamine 8