In a 78‑year‑old patient with worsening dementia, what medications should be used and what are the appropriate doses and dosing frequencies?

Medication Management for Worsening Dementia in a 78-Year-Old

In a 78-year-old with worsening dementia, you should critically reassess whether to continue or discontinue current cognitive enhancers (cholinesterase inhibitors and memantine) rather than automatically increasing doses, as worsening dementia may indicate treatment failure and signal the need for deprescribing. 1

Critical Decision Point: Evaluate for Discontinuation First

The 2020 Canadian Consensus Conference provides clear criteria for when to stop dementia medications in the context of worsening disease 1:

For Cholinesterase Inhibitors (donepezil, rivastigmine, galantamine), consider discontinuation if:

• Clinically meaningful worsening has occurred over the past 6 months despite treatment (in absence of delirium or acute medical illness)
• No benefit was ever observed (no improvement, stabilization, or decreased rate of decline)
• The patient has reached severe/end-stage dementia (dependent in most basic ADLs, unable to respond to environment)
• Intolerable side effects have developed (severe nausea, vomiting, weight loss, anorexia, falls)
• Poor medication adherence prevents safe use 1

For Memantine, apply the same discontinuation criteria if the patient has been on it >12 months 1

If Continuing Treatment is Appropriate

Standard Dosing for Cognitive Enhancers

Cholinesterase Inhibitors:

• Donepezil: Start 5 mg once daily, increase to 10 mg daily after 4-6 weeks (most commonly prescribed) 2
• Rivastigmine: Start 1.5 mg twice daily, titrate by 1.5 mg increments every 2-4 weeks to target 3-6 mg twice daily (or transdermal patch 4.6-9.5 mg/24 hours)
• Galantamine: Start 4 mg twice daily, increase by 4 mg increments every 4 weeks to target 8-12 mg twice daily

Memantine:

• Start 5 mg once daily, increase by 5 mg weekly to target dose of 10 mg twice daily (or 28 mg extended-release once daily)

Important Caveat on Dosing

Research shows that in real-world geriatric practice, average prescribed doses are often lower than recommended effective doses, particularly for rivastigmine, galantamine, and memantine 2. However, in a 78-year-old with worsening dementia, increasing doses is unlikely to reverse decline and may increase adverse events.

Managing Behavioral and Psychological Symptoms

If worsening includes agitation, aggression, or psychosis:

• Do NOT discontinue cholinesterase inhibitors until these symptoms stabilize, unless the medication clearly worsened them 1
• If cognitive enhancers previously reduced neuropsychiatric symptoms, continue them even with cognitive decline 1

For severe agitation requiring additional treatment:

• Brexpiprazole has the strongest evidence and best safety profile 3
• Citalopram (10-30 mg daily) is preferred when prioritizing safety over antipsychotics 4, 3
• Risperidone (0.5-2 mg daily) or aripiprazole are effective but require monitoring for cerebrovascular events and extrapyramidal symptoms 4, 3

Deprescribing Protocol (If Discontinuation Indicated)

Follow this gradual taper to minimize withdrawal effects 1:

1. Reduce dose by 50% every 4 weeks until reaching the initial starting dose
2. Continue at starting dose for 4 weeks
3. Then discontinue completely
4. Monitor closely: If clinically meaningful worsening occurs (cognition, function, neuropsychiatric symptoms), reinitiate treatment 1

Common Pitfalls to Avoid

• Don't automatically increase doses when dementia worsens—this often indicates treatment failure, not underdosing
• Don't use cognitive enhancers for non-approved dementias (frontotemporal dementia, other neurodegenerative conditions)—they should be discontinued 1
• Avoid polypharmacy: 41.3% of patients have concomitant interacting drugs 2; anticholinergic burden is particularly problematic 5
• Watch for adverse events: 43.5% of cholinesterase inhibitor users develop side effects, mostly gastrointestinal 2
• Consider dysphagia: Progressive dementia often causes swallowing difficulties—orally disintegrating formulations may be needed 6

Type of Dementia Matters

Only continue medications for:

• Alzheimer's disease (AD)
• Parkinson's disease dementia (PDD)
• Dementia with Lewy bodies (DLB)
• Vascular dementia (VD)

For other dementia types, discontinue cognitive enhancers 1