Donepezil is used to reduce the symptoms of mild to moderate and severe Alzheimer’s disease and other types of dementia. Learn how to use the medication, its common side effects, special precautions to watch out for, and more.

What is this medication for?

Donepezil belongs to a class of medications known as acetylcholinesterase inhibitors. It is used to reduce the symptoms of mild to moderate and severe Alzheimer’s disease and other types of dementia, such as:

• Difficulty in remembering recent events, activities, or the names of familiar people or things
• Poor concentration and judgment

It will not cure or stop the dementia from getting worse, but it may improve the ability to think in some patients and slow down the worsening of these symptoms.

Check with your healthcare professional if you are unsure why you are given this medication.

How should I take or use this medication?

• Take your medication according to the instructions stated on the medication label.
• Donepezil can be taken with or without food.
• Donepezil is available as tablet and orodispersible tablets. Orodispersible tablets means that the tablets melt upon contact with saliva and can be taken with or without water. Please check with your healthcare professional if you are unsure which type of tablet you are taking.
• To take orodispersible tablets:
  1. Dry your hands. The tablets will melt if your hands are wet.
  2. Remove the tablet from its packaging when you are ready to use it. Do not remove it too early from the blister pack.
  3. Place the tablet on your tongue and allow it to melt before swallowing. You may take it with or without water. 
• Donepezil needs to be taken regularly for a few weeks before you can feel its full benefits. You should not stop taking this medication even if you do not feel better at the beginning. Continue to take this medication even after you feel better to prevent your symptoms from returning.
• Do check with your doctor on how long you will have to be on this medication.
• Do not stop taking or adjust the dose of this medication without checking with your doctor.

What should I do if I forget to take or use this medication?

• If you forget to take a dose, take it as soon as you remember. However, if more than half of the time to the next dose has passed, skip the missed dose and take the next dose at your usual timing.
• For example, for a medication to be taken once daily at 8am, and you missed your dose at 8am, take it as soon as you can remember before 8pm. Do not take two doses to make up for the missed dose.
• If you forget to take Donepezil for more than 1 week, speak to your doctor before restarting it. You may need to restart it at a lower dose.

What precautions should I take when taking or using this medication?

Inform your healthcare professional if: 

• You are allergic to this medication or any of the other ingredients of this medication
• You are pregnant, planning to become pregnant, or breastfeeding. If you are pregnant and/or breastfeeding, your doctor would have discussed the potential benefits and side-effects with you and should you have further questions or concerns, do consult your doctor.
• You are taking any other medications (including those that can be bought without a prescription), supplements,  traditional medications and herbal remedies. Some of them may affect how this medication works or cause serious drug interactions.
• You have or have ever had:
  • Other drug allergies
  • Medical conditions such as:
    • Heart problems, slow or irregular heartbeat
    • Liver disease
    • Seizures (fits)
    • Respiratory diseases
    • Stomach or intestinal ulcers
    • Difficulty in passing urine

What are some common side effects of this medication?

• Drowsiness or feeling tired
  • Avoid driving or taking part in activities that require concentration
  • Discuss with your doctor if you can take your medication at a different time of the day
• Nausea, vomiting
  • Take the medication with or after food
  • Take small but frequent meals and avoid fatty or spicy food
• Diarrhoea
  • Drink more water to replace fluid loss
• Dizziness
  • Get up slowly from a sitting or lying down position
• Difficulty sleeping
  • Discuss with your doctor if you can take your medication at a different time of the day
  • Listen to relaxing music at bedtime
  • Avoid eating or drinking too much before bedtime
  • Limit caffeine intake (such as coffee, tea or energy drinks) at least 8 hours before bedtime
• Headache, loss of appetite or weight loss, muscle cramps

Most of the side effects listed here will improve with time. Speak with your doctor if any of them continues, worsens or affects your daily life.

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following: 

• Swollen face/eyes/lips/tongue
• Difficulty in breathing
• Itchy skin rashes over your whole body

Rarely this medication may cause:

• Seizures (fits)
• Slow heartbeat
• Fast or irregular heartbeat, fainting episodes (signs and symptoms of an abnormal heart beating rhythm (prolonged QTc interval))
• Difficulty or pain in passing urine
• Seeing or hearing things that are not present (hallucinations)
• Severe stomach pain and vomiting of blood or material that looks like coffee grounds; bloody or black tarry stools (signs and symptoms of bleeding in the stomach or intestines)
• Confusion, high fever, severe muscle stiffness, irregular blood pressure (signs and symptoms of neuroleptic malignant syndrome)
• Dark-coloured urine with unexplained muscle pain, tenderness, or weakness (signs and symptoms of muscle trauma condition known as rhabdomyolysis)
• Anxiety, agitation or low mood     

If you experience any of these side effects, you should stop your medication and inform your healthcare professional immediately.

What food or medication should I avoid when I take or use this medication?

Avoid drinking alcohol while taking Donepezil as it can cause excessive sleepiness.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How do I throw away this medication safely?

Pack this medication into a trash bag and seal it tightly before throwing it into the rubbish chute or bin.

Disclaimer

Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on Feb 2025