Phenytoin for epilepsy

About phenytoin

If you have epilepsy, it means that you have had more than one unexplained fit, or seizure. 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 functions of your body, so the symptoms that occur during a seizure will 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. The seizures can be prevented in most people by suitable antiepileptic medication. Phenytoin is a commonly used medicine. It works by stabilising the electrical activity of your brain, which prevents the seizures from occurring.

Phenytoin is also prescribed as a treatment for severe burning or stabbing pains in the face, a nerve pain called trigeminal neuralgia. This is because it can modify some types of pain. If you have been given phenytoin for this reason, ask your doctor if you have questions about your treatment.

Before taking phenytoin

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 (or your child if you are their carer) start taking phenytoin it is important that your doctor knows:

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

• If you have any problems with the way your liver works.

• If you have a rare inherited blood disorder called porphyria.

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

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

How to take phenytoin

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

• Take phenytoin exactly as your doctor tells you to. Your dose will be printed on the label of the pack to remind you about what the doctor said. It is usual to start treatment on a low dose, and then for the dose to be increased gradually to a regular maintenance dose.

• It is important you try to take your doses at the same times each day. Having a routine will help you to remember to take your doses regularly. Although phenytoin can be taken before a meal, it is better taken during or straight after a meal.

• If you are taking phenytoin chewable tablets (Epanutin® Infatabs), you can chew the tablet to help you swallow or you can swallow the tablet in the usual way with a drink of water.

• If you are taking phenytoin oral liquid medicine (Epanutin® suspension), make sure that you shake the bottle well before you measure out your dose.

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

Getting the most from your treatment

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

• Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. You will need to have blood tests from time to time.

• While you are being treated for epilepsy there is a small risk that you may develop mood changes, distressing thoughts and feelings about suicide. If this happens, you must tell your doctor about it straightaway.

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

• Different formulations and brands of phenytoin can act in a slightly different way in your body. Because of this, it is important that you continue to take phenytoin 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.

• If you drink alcohol, ask your doctor for advice. Your doctor may advise you not to drink alcohol while you are on this medicine because it can alter the amount of phenytoin in your body.

• If you buy any medicines, check with a pharmacist that they are suitable for you to take with your antiepileptic medication. Some indigestion remedies can interfere with the amount of phenytoin in your body.

• Many antiepileptic medicines can harm an unborn child. If you are a woman, make sure you have discussed with your doctor which types of contraception are suitable for you and your partner. Phenytoin can make oral contraceptives less effective. Your doctor will advise you on other types of contraception such as an intra-uterine device (IUD) and barrier methods. You should use effective contraception throughout treatment with phenytoin and for one month after stopping. If you want to have a family, discuss this with your doctor so that you can be given advice from a specialist before you become pregnant.

• You need to take phenytoin regularly every day. Do not stop taking it unless your doctor tells you to stop. Stopping treatment suddenly can cause problems and your doctor will want you to reduce your dose gradually if this becomes necessary.

Can phenytoin cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with phenytoin. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

If you experience any other symptoms which you think may be due to phenytoin, speak with your doctor or pharmacist for further advice.

How to store phenytoin

• 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