What is the best initial medication for an elderly patient with short-term memory loss, specifically Alzheimer's disease?

Best Initial Medication for Elderly Patient with Short-Term Memory Loss

Donepezil (Aricept) is the recommended first-line medication for a 78-year-old patient with short-term memory loss due to Alzheimer's disease, starting at 5 mg once daily. 1

Cholinesterase Inhibitor Options

Cholinesterase inhibitors are the mainstay of pharmacological treatment for Alzheimer's disease. The available options include:

Donepezil (Aricept)

• Recommended initial dosage of 5 mg once daily, which can be increased to 10 mg once daily after 4-6 weeks if needed 1
• Advantages include once-daily dosing, no hepatotoxicity, and mild side effects 1
• Has shown clinically meaningful improvements in cognitive and global function in patients with mild to moderate Alzheimer's disease 2
• Side effects include nausea, vomiting, and diarrhea, which can be reduced by taking with food 1
• Some patients may experience initial increase in agitation that typically subsides after a few weeks 1

Rivastigmine (Exelon)

• Initial dosage of 1.5 mg twice daily, with gradual titration up to 6 mg twice daily 1
• Requires twice-daily dosing, which may affect adherence in patients with memory issues 1
• Side effects include nausea, vomiting, diarrhea, headaches, dizziness, and weight loss 1

Galantamine (Reminyl)

• Initial dosage of 4 mg twice daily, taken with meals 1
• Requires twice-daily dosing 1
• Contraindicated in patients with hepatic or renal impairment 1
• Common side effects include nausea, vomiting, and diarrhea 3

Tacrine (Cognex)

• Now considered a second-line agent due to side effect profile 1
• Causes elevation of liver enzyme levels in 40% of treated patients, requiring biweekly liver tests 1
• Must be administered four times daily due to short half-life 1

Rationale for Recommending Donepezil

Donepezil is preferred for this 78-year-old patient for several reasons:

• Once-daily dosing improves medication adherence in elderly patients with memory problems 1
• No hepatotoxicity, unlike tacrine 1
• Better side effect profile compared to other cholinesterase inhibitors 2
• Extensive clinical evidence supporting its use in mild to moderate Alzheimer's disease 2, 4
• Can be taken with food to minimize gastrointestinal side effects 1

Dosing Considerations for Elderly Patients

• Start with 5 mg once daily for at least 4-6 weeks before considering dose increase 1
• Dose can be increased to 10 mg daily if well-tolerated and greater efficacy is needed 1
• Higher doses (up to 23 mg) may be considered for moderate to severe disease progression, but with increased risk of side effects 5
• Take with evening meal if insomnia or nightmares occur 1

Monitoring Response to Treatment

• Beneficial response may take 6-12 months to assess properly 1
• Response should be determined by:
  • Physician's global assessment of the patient 1
  • Primary caregiver's report 1
  • Evidence of behavioral or functional changes 1
• Brief mental status tests are relatively insensitive measures of cholinesterase inhibitor effects 1

Common Pitfalls and Caveats

• Cholinesterase inhibitors provide modest benefits (5-15% over placebo) - set realistic expectations with patient and family 1
• Consider discontinuation if:
  • Side effects develop and do not resolve 1
  • Adherence is poor 1
  • Deterioration continues at pre-treatment rate after 6-12 months 1
  • Patient progresses to severe or end-stage dementia 1
• Patients who don't respond to one cholinesterase inhibitor may respond to another 1
• Avoid in patients with mild cognitive impairment (MCI) without dementia, as evidence doesn't support use in this population 1, 6

Additional Considerations

• Vitamin E (2000 IU daily) may be considered as an adjunct therapy to slow functional decline 1
• Non-pharmacological interventions should be implemented alongside medication:
  • Establish predictable routines 1
  • Simplify tasks and provide clear instructions 1
  • Create a safe environment 1
  • Use calendars, clocks, and labels for orientation 1