Memantine

What is memantine?

Memantine is a prescription-only medicine used to treat moderate to severe Alzheimer’s disease, a form of dementia. While it is not a cure, it can help reduce symptoms such as memory loss, confusion, and problems with thinking and reasoning. It is available under brand names such as Ebixa, Nemdatine, and Valios[1]. 

What is memantine used for?

Memantine is prescribed for moderate to severe Alzheimer’s disease and cases where other dementia medications (such as donepezil) are not effective or suitable. It is also used for dementia with Lewy bodies, mixed dementia (more than one type), and corticobasal degeneration[1]. 

How does memantine work?

Memantine blocks the action of a brain chemical called glutamate. In Alzheimer’s disease, excessive glutamate can overstimulate nerve cells and cause damage. Memantine helps protect brain cells by reducing this harmful activity[1]. 

Who can take memantine?

Memantine is generally suitable for most adults with moderate to severe Alzheimer’s. It may not be appropriate for those who[1]: 

• Have severe kidney problems 

• Have a history of seizures or epilepsy 

• Have high blood pressure, heart failure, or have ever had a heart attack 

• Are allergic to memantine 

Please tell your doctor or pharmacist about any conditions you may have or medication you take before you start treatment, and always follow the instructions in the Patient Information Leaflet[2].  

What is the typical dosage of memantine

Memantine comes as 5mg, 10mg, 15mg and 20mg tablets. It also comes as a liquid that you swallow, containing 10mg in 1ml. Memantine is usually started at a low dose and gradually increased to reduce potential side effects. For the tablets, start with 5mg once a day, increasing by 5mg each week, up to the usual maintenance dose of 20mg daily (as a single dose or split into two 10mg doses). For the liquid, take one 0.5ml dose, once a day, increasing by 0.5ml weekly until your dose is 2ml (20mg)[1]. 

People with kidney problems may require a lower dose. 

How do you take memantine?

Take once a day, at the same time each day. It can be taken with or without food. Dissolvable tablets should be placed on your tongue and allowed to dissolve before drinking water. Soluble tablets should be dissolved in half a cup of water and drunk straight away. Liquid comes in a pump dispenser or in a bottle with a syringe[1]. 

Can you stop taking memantine?

Do not stop taking memantine suddenly without advice from your doctor. Stopping can cause symptoms to return or worsen. Your doctor or pharmacist can help you stop safely if needed[1]. 

What do you do if you take too much memantine?

An overdose of memantine may cause[1]: 

• Drowsiness 

• Dizziness 

• Confusion 

• Aggression 

• Hallucinations 

If this happens, seek urgent medical attention by calling 111 or going to A&E. 

What do you do if you forget to take memantine?

If you forget a dose, take the missed dose as soon as you remember. If it’s nearly time for your next dose, skip the missed one. Do not take two doses at once[1]. 

What medicines can’t you take with memantine?

Memantine may interact with: 

• Amantadine (used to treat Parkinson’s disease and multiple sclerosis) 

• Ketamine (for depression or severe pain) 

• Dextromethorphan (found in some cough medicines) 

• Warfarin (for blood clots) 

• Mental health medication like haloperidol, chlorpromazine, or olanzapine 

• Some antacids and diuretics 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2]. 

What are the side effects of memantine?

The most common side effects (affecting up to 1 in 10 people) include[1]: 

• Headache 

• Dizziness or sleepiness 

• Constipation 

The rare, but more serious, side effects include[1]: 

• Hallucinations 

• Symptoms of heart failure – swollen extremities, breathlessness, extreme exhaustion, persistent cough, or a fast heart rate 

• Symptoms of pancreatitis – severe stomach pain, sickness, nausea, diarrhoea, or a high temperature 

• Blood clots – throbbing or cramping pain, swelling, redness, or warmth in legs or arms 

• Liver problems – yellowing of eyes or skin, and pale poo or dark pee  

• Seizures 

You should contact your GP if you experience any of these symptoms. In rare cases, the medicine may cause a serious allergic reaction (anaphylaxis). You should call 999 or visit A&E immediately if you believe this is happening[1]. 

Symptoms of anaphylaxis include[1]:  

• Difficulty breathing  

• Tightness in throat and chest  

• Swelling of the tongue or throat  

• Feeling faint or dizzy  

• Blue/grey skin or lips  

• Loss of consciousness 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Frequently asked questions about memantine

Is memantine a cure for Alzheimer’s? 
No. It helps manage symptoms but does not cure the disease[1]. 

How long does memantine take to work? 
It may take a few weeks to notice an effect[1]. 

Can I drink alcohol while taking memantine? 
It is best to limit alcohol, as it may increase side effects such as drowsiness or dizziness[1]. 

Is memantine safe for older adults? 
Yes. Memantine is commonly prescribed to older adults with dementia[1]. 

Can I take herbal supplements with memantine? 
Always check with a doctor or pharmacist, as some supplements may interact with memantine[1]. 

For the official NHS guide to memantine, visit their website.