Can Aricept (donepezil) or Namenda (memantine) be given to patients with dementia and cerebral amyloid angiopathy (CAA)?

Donepezil and Memantine in Dementia with Cerebral Amyloid Angiopathy

Both donepezil (Aricept) and memantine (Namenda) can be used in patients with dementia and cerebral amyloid angiopathy (CAA), with donepezil recommended for mild to moderate dementia and memantine for moderate to severe dementia. The decision should be guided by dementia severity and potential risk of intracerebral hemorrhage (ICH).

Risk Assessment for CAA Patients

CAA significantly increases the risk of recurrent intracerebral hemorrhage compared to non-CAA-related ICH:

• CAA-related ICH recurrence: 7.4% per year
• Non-CAA-related ICH recurrence: 1.1% per year 1

Risk factors for recurrent ICH that should be evaluated include:

• Lobar location of initial ICH
• Older age
• Presence and number of microbleeds on MRI
• Presence of cortical superficial siderosis on MRI
• Poorly controlled hypertension 1

Treatment Algorithm for Dementia with CAA

1. Mild to Moderate Dementia (MMSE >14)

• First choice: Donepezil (5-10 mg daily)
  • Benefits: Improves cognition and global function in both Alzheimer's and vascular dementia 1
  • Monitoring: Watch for gastrointestinal side effects (nausea, diarrhea, anorexia) 1

2. Moderate to Severe Dementia (MMSE 5-14)

• First choice: Memantine (target dose 20 mg daily)
  • Benefits: Improves cognition, behavior, and mood in moderate to severe dementia 1
  • Side effects: Generally milder than cholinesterase inhibitors (headaches, dizziness) 1

3. Moderate to Severe Dementia Already on Donepezil

• Consider adding: Memantine to donepezil
  • Benefits: Combination therapy shows significant benefits in cognition, activities of daily living, and global outcomes 2
  • Evidence: Randomized controlled trials show the combination is more effective than donepezil alone 2

Special Considerations for CAA Patients

1. Hemorrhage Risk Management:

   • Carefully control hypertension
   • Avoid anticoagulants when possible
   • Monitor for neurological symptoms that might indicate new microbleeds

2. Medication Cautions:

   • SSRIs should be used with caution as they may increase ICH risk, especially when combined with anticoagulants 1
   • Start at lower doses and titrate slowly to minimize side effects

3. Non-Pharmacological Approaches:

   • Cognitive therapy should be considered for all patients 1
   • Vascular risk factor management is essential 1

Efficacy Evidence

• Donepezil has shown consistent improvement in cognition and global function in both Alzheimer's disease and vascular dementia 1
• Memantine demonstrates beneficial effects on cognitive function, activities of daily living, and mood in moderate to severe Alzheimer's disease and vascular dementia 1
• Combination therapy with memantine and donepezil provides additional benefits across multiple domains compared to cholinesterase inhibitor monotherapy 3

Common Pitfalls to Avoid

1. Not assessing ICH risk: Always evaluate the patient's risk of recurrent hemorrhage before initiating therapy
2. Inappropriate dosing: Start with lower doses and titrate slowly in CAA patients
3. Overlooking drug interactions: Be cautious with medications that may increase bleeding risk
4. Neglecting non-pharmacological interventions: These should complement drug therapy
5. Failing to monitor: Regular follow-up is essential to assess both efficacy and adverse effects

While there are no specific trials of treatment for CAA-related cognitive impairment, the evidence supports using these medications with appropriate caution regarding the increased hemorrhage risk in this population.