Medication Information Leaflet

What is this medication for?

Memantine belongs to a class of medication known as N-Methyl-D-Aspartate (NMDA) antagonists. It is used to reduce the symptoms of moderate to 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 judgement

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/use this medication?

  • Follow the instructions on your medication label and take this medication as prescribed by your doctor.
  • This medication may be taken with or without food.
  • This medication needs to be taken regularly for a few weeks before you feel its full effects. Therefore, do not stop taking this medication even if there are no signs of improvement at the beginning.
  • You may check with your doctor on how long you will have to be on this medication.
  • Do not stop taking your medication without checking with your healthcare professional.

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

If you forget to take a dose, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose. Then take the next dose at your usual timing. Do not take two doses to make up for the missed dose.

What precautions should I take?

Inform your healthcare professional if: 
  • You are allergic to this medication or any of the other ingredients of this medication
  • You are taking any other medications including over-the-counter medications, supplements, traditional Chinese medicine and herbal remedies. Some of these 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, kidney or liver disease
      • Eye disease
      • Seizures (fits)

What are some common side-effects of this medication?

The mentioned side effects generally affect up to 10% of patients.

  • Light-headedness (especially during a sudden change in posture)
    • Get up slowly from a sitting or lying down position to avoid falling over
  • Feeling tired or drowsy
    • Discuss with your doctor if you can take this medication at a different time of the day
    • Avoid driving or engaging in activities requiring concentration
  • Diarrhoea
    • Drink plenty of water to replace loss of fluids
  • Constipation
    • Drink more water (if not on fluid-restricted diet), eat more high-fibre foods, and exercise regularly
    • Speak to your doctor or pharmacist if you need a medication to help with your constipation
  • Headache
Most of the side effects listed here will improve with time. Speak to your doctor if they are bothersome, get worse or are affecting 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:
  • Confusion
  • Seeing or hearing things that are not present (hallucinations)
  • Chest pain, irregular or slow heartbeat
  • Severely increased heart rate or blood pressure
  • Severe dizziness, fainting episodes
  • Sudden severe headache or sudden numbness/weakness on one side of your body (signs and symptoms of stroke)
  • Mood changes or low mood
  • Seizures (fits)
If you experience any of these side effects, you should stop your medication and inform your healthcare professional immediately.

Please also take note that not all possible side effects are listed above. If you have any concerns about your medication, please consult your doctor or pharmacist.

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

Avoid drinking alcohol while taking this medication as it may cause too much drowsiness.

Inform your doctor before making drastic changes to your diet. (E.g. switching from a meat-based diet to a vegetarian diet)

How should I store this medication?

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

How should 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.

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 Oct 2021
Back to Top