Should Alzheimer's Medications Be Stopped During Infection?
No, Alzheimer's disease medications (cholinesterase inhibitors and memantine) should generally be continued during acute infections, though temporary dose reduction or holding may be warranted in specific clinical scenarios involving severe illness, delirium, or significant gastrointestinal symptoms.
Clinical Reasoning
The question addresses a common clinical dilemma, but the available evidence does not directly support routine discontinuation of AD medications during infections. Here's the algorithmic approach:
When to Continue AD Medications During Infection
Most infections do not require stopping AD medications 1. The primary considerations are:
- Mild to moderate infections (urinary tract infections, upper respiratory infections, uncomplicated pneumonia): Continue medications at current doses
- Stable gastrointestinal tolerance: If the patient is not experiencing nausea, vomiting, or diarrhea from the infection itself, continue medications
- No delirium present: When mental status remains at baseline or near-baseline
When to Consider Temporary Modification
Hold or reduce doses in these specific scenarios:
- Severe gastrointestinal symptoms: Cholinesterase inhibitors (donepezil, galantamine, rivastigmine) cause dose-related GI adverse effects including nausea, vomiting, and diarrhea 2. When infection causes significant GI symptoms, adding medication-induced GI effects creates unnecessary burden
- Bradyarrhythmia risk: Cholinesterase inhibitors can cause bradycardia 1. In severe sepsis or infections with hemodynamic instability, temporarily holding these medications is prudent
- Acute delirium: During florid delirium from infection, the modest cognitive benefits of these medications are overshadowed by the acute confusional state. Temporary discontinuation simplifies the medication regimen during acute illness
Important Caveats
The relationship between infections and AD is bidirectional and complex. Persons with AD have substantially higher infection rates - at diagnosis, the infection hospitalization rate is 15 per 100 person-years compared to 9 per 100 person-years in matched controls 3. The infection rate increases dramatically 1-2 years before AD diagnosis and continues rising after diagnosis 3.
Pneumonia and genitourinary infections are the most common in AD patients 3, and systemic infections may actually alter cortical transcriptional signatures and reshape neuroinflammatory programs in the AD brain 4.
Practical Algorithm
- Assess infection severity: Mild/moderate vs. severe/septic
- Evaluate GI symptoms: Significant nausea/vomiting/diarrhea present?
- Check for delirium: Acute confusional state vs. baseline cognition?
- Monitor cardiac status: Bradycardia or hemodynamic instability?
If all answers are "no" to concerning features → Continue medications
If "yes" to severe illness, significant GI symptoms, or delirium → Consider temporary hold (3-7 days) and restart after acute illness resolves
Deprescribing Context
The 2021 Mayo Clinic polypharmacy guidelines note that cholinesterase inhibitors are "safe to taper to off, especially when there is perceived lack of benefit" 1. However, this refers to permanent discontinuation in advanced dementia, not temporary holds during acute illness. The guidelines specifically note these medications are "indicated for mild to moderate dementia" and have "lacking long-term benefit, particularly in advanced dementia" 1.
The key distinction: Temporary holds during acute infection differ from permanent discontinuation decisions based on disease stage and lack of benefit.
Restarting After Infection
Once the acute infection resolves and GI symptoms improve, restart AD medications at the previous dose if they were providing benefit. There is no need to retitrate from lower doses unless the medication was held for an extended period (>2-3 weeks).