Can I start donepezil (Aricept) in a patient with a Montreal Cognitive Assessment score of 16/30 while awaiting a computed tomography scan?

Can You Start Aricept on a Patient with a MoCA of 16/30 While Waiting for a CT Scan?

Yes, you can start donepezil (Aricept) in this patient with moderate cognitive impairment (MoCA 16/30) while awaiting the CT scan, provided you have ruled out delirium and other acute reversible causes of cognitive decline. 1

Clinical Reasoning

A MoCA score of 16/30 indicates moderate cognitive impairment and falls well within the range where cholinesterase inhibitors demonstrate benefit. The evidence supports treatment initiation in patients with mild to moderate dementia (typically MMSE 10-26, which correlates with moderate impairment at MoCA 16/30). 2, 3

Key Considerations Before Starting Treatment

Rule out reversible causes first 1:

• Delirium from infections or toxic-metabolic causes
• Acute stroke or other vascular events
• Depression
• Medications with anticholinergic effects
• Metabolic derangements

Brain imaging is recommended but not mandatory before treatment initiation 1. The 2020 Canadian Consensus Conference guidelines indicate that anatomical neuroimaging should be obtained in most situations, particularly with:

• Onset of cognitive symptoms within the past 2 years
• Unexpected decline in cognition or function
• Recent head trauma
• New neurological signs
• History of cancer or risk for intracranial bleeding 1

However, imaging is primarily to identify treatable structural lesions (subdural hematomas, tumors, normal pressure hydrocephalus) and to support differential diagnosis—not as an absolute prerequisite for starting symptomatic treatment. 1

Practical Implementation

Starting Donepezil

Initial dosing 4:

• Start at 5 mg once daily
• Increase to 10 mg once daily after 4-6 weeks if well tolerated
• Take with food to minimize gastrointestinal side effects 4, 2

Expected Timeline and Outcomes

Cognitive benefits typically appear within 3 weeks 5, 2, though a 6-12 month assessment period is necessary to fully evaluate treatment response. 4

Realistic expectations 5, 4:

• Approximately 20-35% of patients show a 7-point improvement on neuropsychological tests (equivalent to reversing one year's decline)
• This represents a 5-15% benefit over placebo
• Benefits are modest and represent symptom management, not disease cure or reversal

Safety Profile

Donepezil is generally well tolerated 5, 2:

• Most adverse effects are mild, transient gastrointestinal symptoms (nausea, diarrhea, vomiting)
• Side effects are dose-related and reduced when taken with food
• No hepatotoxicity (unlike tacrine) 5
• Discontinuation rates due to adverse effects are comparable to placebo 4

Common Pitfalls to Avoid

Do not delay treatment unnecessarily 1. While brain imaging should be obtained, waiting weeks for a CT scan before initiating symptomatic treatment deprives the patient of potential benefit during that time, provided acute reversible causes have been excluded clinically.

Avoid premature discontinuation 4. Initial gastrointestinal side effects often resolve within weeks and can be minimized by:

• Taking medication with meals
• Gradual dose titration (waiting 4-6 weeks before increasing from 5 mg to 10 mg)

Set realistic expectations with patients and families 5, 4. Emphasize that:

• Treatment slows decline rather than reversing it
• Benefits are modest but meaningful
• Assessment requires 6-12 months of continuous therapy

When to Obtain Urgent Imaging

Expedite the CT scan if any of the following are present 1:

• New focal neurological signs (Babinski sign, asymmetric weakness)
• Recent significant head trauma
• New onset severe headache or seizures
• History of cancer with risk for brain metastases
• Symptoms suggesting normal pressure hydrocephalus (gait disturbance, urinary incontinence)
• Anticoagulation use or bleeding risk

Algorithm for Decision-Making

1. Clinical assessment: Rule out delirium, acute stroke, depression, and medication effects 1
2. If acute reversible causes excluded: Start donepezil 5 mg daily with food 4
3. Order CT scan: Obtain within reasonable timeframe (days to weeks, not months) 1
4. Review imaging when available: Adjust diagnosis and management based on findings 1
5. Reassess at 4-6 weeks: Increase to 10 mg daily if tolerated 4
6. Full assessment at 6-12 months: Evaluate cognitive, functional, and behavioral response using caregiver input and global clinical impression 4

The key principle: Symptomatic treatment with donepezil can and should be initiated based on clinical diagnosis in moderate dementia, while diagnostic workup (including imaging) proceeds in parallel. 1