In an 80-year-old man with worsening memory, a mental status exam score of 25/30, normal vitamin B12 and thyroid‑stimulating hormone (TSH) levels, a PHQ‑2 (Patient Health Questionnaire‑2) score of zero, and minimal weekly walking, what is the best next step in managing his early Alzheimer‑type cognitive decline: aerobic exercise, ginkgo biloba, or donepezil?

Donepezil is the Best Next Step

For this 80-year-old man with mild cognitive impairment (MMSE 25/30) consistent with early Alzheimer's disease, donepezil should be initiated immediately. The FDA-approved indication for donepezil explicitly includes mild, moderate, and severe Alzheimer's disease, and the drug has demonstrated consistent improvements in cognition and global function 1. While aerobic exercise and ginkgo biloba have supportive evidence, donepezil represents the evidence-based pharmacologic standard of care with the strongest regulatory approval and guideline support.

Why Donepezil First

The FDA labeling clearly states that donepezil tablets are indicated to treat mild, moderate, and severe Alzheimer's disease 1. With an MMSE of 25/30, this patient falls into the mild dementia range where donepezil has proven efficacy. The 2008 guideline evidence demonstrates that donepezil consistently improves cognition (measured by ADAS-cog) and global function assessment (CIBIC-plus), with the CIBIC-plus showing clinically significant changes 2. These benefits are maintained throughout treatment duration in controlled trials.

Start with donepezil 5 mg once daily, then titrate to 10 mg after 4-6 weeks based on tolerability 1. The drug can be taken with or without food, and the most common side effects are gastrointestinal (nausea, diarrhea, vomiting) which are dose-related and typically mild 1.

Why Not Aerobic Exercise as Primary Treatment

While the 2021 physical activity guidelines emphasize that exercise prevents functional and cognitive decline in older adults 3, this patient's minimal activity (walking 0.5 miles weekly) falls far short of the WHO recommendation of 150-300 minutes of moderate-intensity exercise per week. Exercise should be prescribed as adjunctive therapy, not as a replacement for pharmacologic treatment in established cognitive impairment. The guidelines focus on prevention and maintaining function rather than treating diagnosed dementia 3.

Recommendation: Increase aerobic exercise to at least 150 minutes weekly of moderate-intensity activity (brisk walking) alongside donepezil 3. This addresses both pharmacologic treatment and lifestyle modification.

Why Not Ginkgo Biloba as Primary Treatment

The evidence for ginkgo biloba is inconsistent and controversial. While some recent studies suggest potential benefit when added to donepezil 4, 5, the highest-quality systematic reviews reveal significant limitations:

• The 2007 Cochrane review concluded that "evidence that Ginkgo has predictable and clinically significant benefit for people with dementia or cognitive impairment is inconsistent and unconvincing" 6
• The 2016 meta-analysis noted that methodological quality was "moderate to poor" and findings were inconsistent 7
• Most positive studies used ginkgo as an adjunct to conventional therapy, not as monotherapy 4, 7

Critical caveat: Ginkgo biloba is not FDA-approved for dementia treatment and lacks the regulatory oversight and standardization of donepezil. If considering ginkgo, it should only be added after establishing donepezil therapy, not used instead of it.

Clinical Algorithm

1. Initiate donepezil 5 mg once daily (take at bedtime to minimize side effects)
2. Prescribe structured aerobic exercise: Target 30 minutes of brisk walking 5 days per week
3. Monitor at 4-6 weeks: If tolerating donepezil well, increase to 10 mg daily
4. Reassess cognition at 3-6 months using MMSE and functional assessments
5. Consider adding ginkgo biloba only if suboptimal response to donepezil at 6 months (though evidence remains mixed)

Important Safety Considerations

Before starting donepezil, screen for:

• Cardiac conduction abnormalities (donepezil can cause bradycardia and heart block) 1
• History of peptic ulcer disease (cholinesterase inhibitors increase gastric acid) 1
• Asthma or COPD (may worsen respiratory symptoms) 1
• Current NSAID use (combined use increases ulcer risk) 1

The PHQ-2 score of zero appropriately rules out depression as a contributor to cognitive symptoms 8, and normal B12/TSH exclude reversible causes 9.

This patient requires immediate pharmacologic intervention with donepezil, not watchful waiting with exercise or unproven supplements alone. The goal is to slow cognitive decline and preserve function while quality of life can still be meaningfully impacted.