Anticonvulsant drugs for the treatment of pain: Gabapentin and Pregabalin

Anticonvulsant drugs are a group of drugs normally used to treat epilepsy which are also useful in treating pain. They are particularly helpful where there is nerve damage, which may result in pain that is burning and shooting in nature. Anticonvulsants work by changing the way nerves send messages to your brain. They can also help you sleep at night as one of the side effects is drowsiness.

It is hoped that anticonvulsants can help you by:

• Reducing pain
• Improving sleep.

Your doctor will usually start you on a low dose and then ask you to gradually increase it until you find the dose which works best for you.

Anticonvulsant drugs usually come in the form of a capsule or tablet and are taken 1 to 3 times a day depending on the instructions from your GP, consultant or specialist nurse. It is advisable to start by taking a dose at bedtime as they can make you feel drowsy.

If you forget a dose, take it as soon as you remember. If it is nearly time for your next dose just miss the dose you forgot. Do not take two doses together.

Anticonvulsants can cause side effects. Most are mild and may be worse in the first few days or when your dose is increased while your body is getting used to them.

The most common are:

• Dizziness
• Drowsiness
• Weight gain/changes in appetite
• Dry mouth
• Problems with abnormal movements such as writhing, jerking movements, stiffness and tremor.

Other common side effects include swelling of the legs, blurred vision and headache. Please note this list is not complete. You may only experience one, or none at all, but it is important you are aware of them. If you are concerned about any side effects you are getting you can contact your GP, consultant or specialist nurse.

If you want to stop taking your anticonvulsant capsules they should not be stopped suddenly. By stopping them suddenly you may experience some side effects. They must be reduced slowly over time, with guidance from your GP, consultant or specialist nurse.

It can take a several weeks for you to notice the full benefit of the anticonvulsants so it is important to continue with them, particularly as you have probably started on a low dose. The doctor will usually prescribe a gradually increasing dose for you to take over several weeks.

If the anticonvulsants help your pain then you can continue to take them for as long as you need them. If you do not feel any improvement in your pain after six to eight weeks speak to your GP, consultant or specialist nurse.

Anticonvulsants may cause drowsiness. If this happens, do not drive.

Alcohol increases the sedative effects of anticonvulsant drugs.

It is best not to drink alcohol when you start taking them. Once settled on a steady dose, you may drink alcohol in moderation but it may make you more drowsy than normal.