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Primidone for epilepsy

You need to take primidone regularly to prevent fits (seizures) from occurring. It is usually taken twice daily.

It may cause you to feel drowsy.

Do not drink alcohol.

Do not suddenly stop taking it as this is likely to make your fits return.

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About primidone

Type of medicine


Used for


Available as

Tablets, oral liquid medicine

If you have epilepsy, it means that you have had repeated fits (seizures). A seizure is a short episode of symptoms caused by a burst of abnormal electrical activity in your brain. Different parts of the brain control different parts and functions of your body. Therefore, the symptoms that occur during a seizure depend on where the abnormal burst of electrical activity occurs. Symptoms that may occur during a seizure can affect your muscles, sensations, behaviour, emotions, consciousness, or a combination of these.

Epilepsy cannot be 'cured', but the seizures can be prevented in most people by suitable anti-epileptic medication. Primidone helps prevent seizures from occurring.

Before taking primidone

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking primidone it is important that your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breastfeeding.

  • If you have breathing problems.

  • If you have ever had problems with drug or alcohol dependence.

  • If you have liver or kidney problems.

  • If you have a rare inherited blood disorder known as porphyria.

  • If you are taking or using any other medicines. This includes any medicines which are available to buy without a prescription, as well as herbal and complementary medicines.

  • If you have ever had an allergic reaction to a medicine.

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How to take primidone

  • Before you start this treatment, read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about primidone and a full list of side-effects which you may experience from taking it.

  • Take primidone exactly as your doctor has told you. It is usually taken twice a day, although to begin with you will be prescribed a small dose to take at bedtime. This will then be increased gradually. Increasing your dose slowly allows your doctor to make sure that you have the dose that best suits you, but avoids any unwanted symptoms. Your dose will be on the label of your pack to remind you how to take the tablets. You need to take primidone regularly to prevent the fits (seizures) from occurring.

  • You can take the tablets before or after food. You may find it helps to swallow them with a drink of water.

  • If you forget to take a dose, take it as soon as you remember. If it is almost time to take your next dose, skip the missed dose and take your next dose when it is due. Do not take two doses together to make up for a forgotten dose.

Getting the most from your treatment

  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.

  • When you first start a new treatment for epilepsy there may be a change in the number or type of fits (seizures) you experience. Your doctor will advise you about this.

  • Different brands of primidone may act in a slightly different way in your body. Because of this your pharmacist will always try to give you tablets from the same manufacturer as you have had before. So, each time you collect a prescription, check to make sure your supply looks the same and that the brand name is the same. If you are unsure, or if you have any questions about your prescription, please ask your pharmacist to check it for you.

  • People with epilepsy must stop driving at first. Your doctor will advise you about when it may be possible for you to resume driving again. This will usually be after a year free of seizures.

  • Do not stop taking this medicine unless your doctor tells you to do so. Stopping it suddenly can cause your seizures to return and your doctor will want you to reduce your dose gradually if this is necessary. Also, taking primidone over a time may lead to your body becoming dependent on it and this is another reason why your doctor will want to reduce your dose slowly.

  • Emotional stress or a lack of sleep could make you more likely to have a seizure. Keeping to a regular sleep pattern and using relaxation exercises can reduce this risk. Speak with your doctor or pharmacist for advice.

  • If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking primidone.

  • If you buy any medicines, check with a pharmacist that they are suitable for you to take alongside primidone.

  • If you are a woman using hormonal contraception ('the pill'), discuss this with your doctor as primidone interferes with the pill, reducing its contraceptive effect. Other methods of contraception will be more suitable for you. If you want to have a family, make sure you discuss this with your doctor well in advance of becoming pregnant. This is so that you can be given advice from a specialist before you become pregnant. If you become pregnant while you are taking primidone, you should tell your doctor straightaway.

  • You are advised not to drink alcohol while you are on primidone. Primidone will make you feel sleepy and drinking alcohol will increase this.

  • While you are taking these tablets, there is a small risk that you may develop mood changes or distressing feelings, and thoughts about suicide. If this happens, you must tell your doctor straightaway.

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Can primidone cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common primidone side-effects

What can I do if I experience this?

Feeling unsteady or tired

Getting up or moving more slowly should help. If this continues, let your doctor know

Feeling sleepy, eyesight problems

Make sure your reactions are normal before you use tools or machines

Feeling sick (nausea)

Stick to simple foods - avoid rich or spicy meals

Feeling short of breath, behavioural changes, mood changes (such as feeling irritable, confused, excited or depressed)

If any of these become troublesome, speak with your doctor

Important: your doctor will have discussed with you the possibility of some less common but more serious side-effects. Let your doctor know straightaway if you experience any of the following:

  • A high temperature (fever) and swollen glands.

  • A severe skin rash.

  • Yellowing of your skin or the whites of your eyes (jaundice).

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

How to store primidone

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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