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Side effects and monitoring of Alzheimer's medications (donepezil, galantamine, rivastigmine, memantine)

Key points

  • Most side effects of Alzheimer’s medications are temporary and manageable with simple steps like taking with food or adjusting the dose slowly.
  • Keep a daily symptom log to track side effects and share with the doctor; this helps guide treatment decisions.
  • Never stop or change the dose without medical advice, as abrupt withdrawal can cause cognitive decline.
  • Watch for dehydration, falls, and heart rate changes, especially in the first few weeks of treatment or after a dose increase.
  • For the rivastigmine patch, rotate application sites daily and watch for skin reactions.
  • Always check for interactions with other medications, especially anticholinergic drugs like Benadryl or certain bladder medications.

General caregiving information, not medical advice. Check medications and major care changes with your clinician.

Step-by-step

  1. Keep a daily symptom log noting date, time, dose, side effects (e.g., nausea, diarrhoea, dizziness, sleep changes), their severity, and duration; bring it to every appointment.

  2. Give donepezil with food to reduce nausea and at bedtime to minimize daytime drowsiness; give galantamine and rivastigmine with meals; take memantine with or without food as directed. Follow the prescriber's gradual dose-escalation schedule exactly.

  3. Encourage small, frequent sips of water or oral rehydration solution if diarrhoea or vomiting occurs; watch for dehydration signs: reduced urination, dark urine, dry mouth, dizziness when standing.

  4. Reduce fall risk: help the person stand slowly, remove loose rugs, secure cords, ensure good lighting, use non-slip bathroom mats.

  5. For rivastigmine patches: apply to clean, dry, hairless skin on upper back, arm, or chest; rotate site daily; remove old patch before applying new one; contact the doctor if rash, swelling, or blistering occurs.

  6. Watch for new or worsening drowsiness, confusion, or unusual behaviour after a memantine dose change—this may indicate excess dose or declined kidney function; report it to the prescriber.

  7. Seek immediate help (call 999) for: very slow pulse (<60 bpm), fainting, difficulty breathing, facial/throat swelling, seizures, or loss of consciousness. For non-urgent concerns call 111 or your GP.

What not to do

  • Never stop, double, or change any Alzheimer's medication dose without medical advice; if a dose is missed, skip it and give the next at the usual time.

  • Do not assume new symptoms (e.g., increased confusion, drowsiness, falls) are always medication-related—an infection, dehydration, or other medical issue could be the cause; always have the doctor investigate.

  • Do not combine cholinesterase inhibitors with anticholinergic drugs (e.g., diphenhydramine, oxybutynin, certain antidepressants) without prescriber or pharmacist review of the full medication list.

  • Do not give over-the-counter anti-diarrhoea medicines without first checking with a pharmacist or doctor due to potential interactions or masked serious problems.

  • Do not start or continue memantine without regular kidney function (eGFR) checks, as drug accumulation can reach harmful levels if kidney function declines.

Practical tools

  • Symptom Tracking Sheet

    A table with columns for Date, Time, Medication & Dose, Side Effect, Severity (1-10), Duration, and Action Taken. Keep it on the fridge or in a notebook. Example: 'Tue 10am – donepezil 5mg – nausea – 4/10 – 2 hours – gave food.' Review before each appointment.

  • Phrases to Say to the Doctor

    A card with scripts: 'My loved one started [medication] on [date]. We've noticed [specific symptom]. It happens [when?], lasts [how long?]. Is this normal? Should we adjust dose or try another? Are there interactions with other medicines? What signs mean we need to stop?'

  • Pill Organiser with Timer

    Weekly pill organiser with compartments for morning, afternoon, evening, plus a daily alarm to prevent missed or double doses. For rivastigmine patches, mark the day on each patch with a soft marker.

  • Dehydration Check Card

    Card listing dehydration signs: peeing less than usual, dark urine, dry mouth, dizziness when standing, confusion. Action: give small sips of water or Dioralyte every 15 minutes; call 111 if no improvement in 2 hours.

  • Fall Prevention Checklist

    Weekly walk-through: remove loose rugs, secure cords, install bathroom grab bars, place nightlights, ensure non-slip shoe soles, clear paths to bedroom and toilet, check safe chair/bed height.

  • Emergency Contact & Medical Info Card

    Card by the phone and in wallet listing 999, 111, GP surgery, pharmacy, next of kin; include current medications, allergies, NHS number, and Alzheimer's medication name and dose.

Discuss with your clinician

Ask your doctor: 'Should my loved one have a baseline ECG before starting donepezil, galantamine, or rivastigmine, especially if they have a history of heart problems?'

Ask: 'How often should we check kidney function (eGFR) for someone taking memantine?'

Ask: 'Is it safe to give this medication if my loved one has a history of seizures or peptic ulcers?'

Ask: 'What should I do if my loved one develops a slow heart rate, fainting, or severe diarrhoea that doesn’t improve?'

Ask: 'Are there any other medications my loved one is taking that could interact with these Alzheimer’s drugs, including over-the-counter ones?'

Ask: 'If side effects are severe, what are the options for switching to a different medication or stopping safely?'

Related guides

Sources