Gabapentin

August 6, 2018

About gabapentin

Gabapentin is used to treat epilepsy.

It's also taken for nerve pain. Nerve pain can be caused by different illnesses including diabetes and shingles, or it can happen after an injury.

Occasionally, gabapentin is used to treat migraine headaches.

Gabapentin is available on prescription. It comes as capsules, tablets, and a liquid that you drink.

Key facts

It's usual to take gabapentin 3 times a day. You can take it with or without food.
Most people who take gabapentin don't get any side effects. The most common ones are feeling sleepy, tired and dizzy. Side effects are usually mild and go away by themselves.
It takes at least a few weeks for gabapentin to work.
You don't need to have epilepsy for gabapentin to help with pain or migraine.
The most common brand name is Neurontin.

Who can and can't take gabapentin

Gabapentin can be taken by adults and children aged 6 years and over.

Gabapentin isn't suitable for some people:

Gabapentin capsules contain gelatin so they may not be suitable for vegetarians and vegans.
Some brands of gabapentin capsules contain lactose, so they may be unsuitable for people who are lactose intolerant.
Gabapentin liquid contains sodium and potassium. If you are on a controlled sodium or potassium diet, or your kidneys don't work well, speak to your doctor before taking this liquid.

To make sure gabapentin is safe for you, tell your doctor if you:

have ever had an allergic reaction to gabapentin or other medicines in the past
have kidney problems
have ever misused or been addicted to a medicine
are trying to get pregnant, are already pregnant or are breastfeeding - gabapentin is usually not recommended in pregnancy or while breastfeeding

How and when to take it

Gabapentin is a prescription medicine. It's important to take it as advised by your doctor.

How much will I take

The usual dose of gabapentin to:

treat epilepsy in adults and older children (aged 12 years and over) is between 900mg and 3,600mg a day split into 3 doses
treat nerve pain in adults is between 900mg and 3,600mg a day split into 3 doses
prevent migraine in adults varies but can be up to 2,400mg a day split into 3 doses

The dose of gabapentin used to treat epilepsy in younger children (aged 6 to 12 years) varies depending on their weight.

If you're taking gabapentin as a liquid, 1ml is usually the same as taking a 50mg tablet or capsule.

How to take it

Swallow gabapentin capsules and tablets whole with a drink of water or juice. Do not chew them.

You can take gabapentin with or without food, but it’s best to do the same each day.

Try to space your doses evenly through the day. For example, first thing in the morning, early afternoon and at bedtime.

If you or your child are taking a liquid, it will come with a plastic syringe or spoon to measure your dose. If you don't have a syringe or spoon, ask your pharmacist for one.

Will my dose go up or down?

To prevent side effects, your doctor will prescribe a low dose to start with and then increase it over a few days.

Once you find a dose that suits you, it will usually stay the same.

How long will I take it for?

If you have epilepsy, it's likely that once your illness is under control you will still need to take gabapentin for many years.

If you have nerve pain, it's likely that once the pain has gone you will continue to take gabapentin for several months to stop it coming back.

What if I forget to take it?

If you forget a dose, take it as soon as you remember. If it is within 2 hours of the next dose, it is better to leave out the missed dose and take your next dose as normal.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

If you have epilepsy, it’s important to take this medicine regularly. Missing doses may trigger a seizure.

If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Taking too much gabapentin by accident can cause unpleasant side effects. These include:

feeling dizzy or sleepy
seeing double
slurring your words
diarrhoea
passing out

If this happens, call your doctor or go to the nearest hospital accident and emergency (A&E) department straight away.

If you need to go to hospital, take the gabapentin packet or leaflet inside it plus any remaining medicine with you.

Side effects

Most people who take gabapentin don't have too much trouble with side effects.

Common side effects

These common side effects may happen in more than 1 in 100 people. They're usually mild and go away by themselves.

Keep taking the medicine but talk to your doctor if these side effects bother you or don't go away:

tiredness or feeling sleepy
dizziness or losing your co-ordination
feeling or being sick (nausea or vomiting)
getting more infections than usual
memory problems
mood changes
swollen arms and legs
blurred vision
dry mouth
difficulties for men getting an erection
weight gain - gabapentin can make you feel hungry

Serious side effects

Very few people taking gabapentin have serious problems.

Tell a doctor straight away if you have a serious side effect, including:

thoughts of harming or killing yourself - a small number of people taking gabapentin have had suicidal thoughts, they can happen after only a week of treatment
yellowing of your skin or whites of your eyes - these may be warning signs of jaundice
unusual bruises or bleeding - these may be warning signs of a blood disorder
long-lasting stomach pain, feeling sick or vomiting - these may be warning signs of an inflamed pancreas
muscle pain or weakness and you are having dialysis treatment because of kidney failure

Serious allergic reaction

In rare cases, it’s possible to have a serious allergic reaction to gabapentin.

A serious allergic reaction is an emergency. Contact a doctor straight away if you think you or someone around you is having a serious allergic reaction.

The warning signs of a serious allergic reaction are:

getting a skin rash that may include itchy, red, swollen, blistered or peeling skin
wheezing
tightness in the chest or throat
having trouble breathing or talking
swelling of the mouth, face, lips, tongue, or throat

These are not all the side effects of gabapentin. For a full list see the leaflet inside your medicines packet.

You can report any suspected side effect to the UK safety scheme.

How to cope with side effects

What to do about:

feeling sleepy, tired or dizzy - as your body gets used to gabapentin, these side effects should wear off. If they don't wear off within a week or two, your doctor may reduce your dose or increase it more slowly. If that doesn't work you may need to switch to a different medicine.
feeling sick (nausea) - take gabapentin with or after a meal or snack. It may also help if you don't eat rich or spicy food.
diarrhoea and being sick (vomiting) - have small but frequent sips of water. It may also help to take oral rehydration solutions which you can buy from a pharmacy or supermarket to prevent dehydration. Don't take any other medicines to treat diarrhoea or vomiting without speaking to a pharmacist or doctor.
blurred vision - don't drive for a week
a dry mouth - chew sugar-free gum or suck sugar-free sweets.
weight gain - gabapentin can make you hungrier so it can be quite a challenge to stop yourself putting on weight. Try to eat a healthy balanced diet without increasing your portion sizes. Don't snack on foods that contain a lot of calories, such as crisps, cakes, biscuits and sweets. If you feel hungry between meals, eat fruit and vegetables and low-calorie foods. Regular exercise will also help to keep your weight stable.

Pregnancy and breastfeeding

Gabapentin is not generally recommended in pregnancy. There's no firm evidence that it's harmful to an unborn baby but for safety, pregnant women are usually advised to take it only if the benefits of the medicine outweigh the potential harm.

If you take gabapentin for epilepsy and become pregnant, don't stop the medicine without talking to your doctor first. It's very important that epilepsy is treated during pregnancy as seizures can harm you and your unborn baby.

If you're trying to get pregnant or have become pregnant you're routinely recommended to take at least 400mcg of a vitamin called folic acid everyday. It helps the unborn baby grow normally.

Pregnant women who take gabapentin are recommended to take a higher dose of folic acid. Your doctor might prescribe a high dose of 5mg a day for you to take during the first 12 weeks of pregnancy.

If you take gabapentin around the time of giving birth, your baby may need extra monitoring for a few days after they’re born because they may have gabapentin withdrawal symptoms.

Gabapentin and breastfeeding

Usually, you can breastfeed while taking gabapentin.

Check with your doctor first though if your baby is premature or has kidney problems.

Tell your doctor if you're trying to get pregnant, are already pregnant or if you're breastfeeding.

Cautions with other medicines

There aren't usually any problems mixing gabapentin with other medicines.

Some indigestion remedies, called antacids, reduce the amount of gabapentin that the body takes in so it doesn't work as well. To stop this happening, take an antacid at least 2 hours before or after your dose of gabapentin.

For safety, tell your doctor if you're taking these medicines before you start gabapentin treatment:

strong painkillers such as morphine - these can increase the tiredness and dizziness you can feel when you start gabapentin
antidepressants such as amitriptyline or fluoxetine
antipsychotic medicines for mental health problems like schizophrenia or bipolar disorder
a medicine to prevent malaria called mefloquine
a weight loss medicine called Orlistat - it may stop gabapentin working as well

Mixing gabapentin with herbal remedies or supplements

There are no known problems with taking herbal remedies and supplements with gabapentin.

However, for safety, tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.

Common questions

How does gabapentin work?

In epilepsy, it's thought that gabapentin stops seizures by reducing the abnormal electrical activity in the brain.

With nerve pain and migraine, it's thought to interfere with pain messages travelling through the brain and down the spine to block pain.

When will I feel better?

It takes a few weeks for gabapentin to work properly. You may still have seizures or pain during this time.

Can I get addicted to gabapentin?

Some people have become addicted to gabapentin after taking it for a long time. If this happens, you will have withdrawal symptoms after you stop taking the medicine.

Talk to your doctor if you're concerned about becoming physically dependent on gabapentin.

Can I get epilepsy medicines for free?

If you have epilepsy, you're entitled to free prescriptions for all of your medicines (not just your epilepsy ones).

To claim your free prescriptions you'll need to have a medical exemption certificate.

The application form for the medical exemption certificate is called FP92A. You can get this from your doctor's surgery. You will need to fill in the form, then your doctor will sign it and send it off.

Are there similar medicines to gabapentin?

Pregabalin (also called Lyrica) is a medicine that works in a similar way to gabapentin. Like gabapentin, it's taken for epilepsy and nerve pain. It can also be taken for anxiety.

However, there are differences between pregabalin and gabapentin. Pregabalin can be taken less often and in different doses to gabapentin.

If you need to change to pregabalin treatment, your doctor will explain how to safely swap from gabapentin.

Should I stick to the same brand of gabapentin?

Most people don't have to stay on the same brand of gabapentin as there is very little difference between brands. Talk to your doctor if you have been asked to switch to a different brand and you are worried about that.

If your epilepsy has been hard to control in the past and the brand you are now taking is working well for you, your doctor may recommend you stay on the same one.

Is it safe to take it for a long time?

There's no evidence that gabapentin has lasting harmful effects even if you take it for many months or years.

What will happen when I come off it?

Don't stop taking gabapentin suddenly, even if you feel fine. Stopping gabapentin suddenly can cause serious problems. If you have epilepsy, stopping gabapentin suddenly can cause seizures that will not stop.

Gabapentin can also build up in the body so that if you're taking it (for epilepsy, pain or migraine) and stop suddenly, you may have a severe withdrawal syndrome. This can have unpleasant symptoms, including:

anxiety
difficulty sleeping
feeling sick
pain
sweating

It's possible to prevent withdrawal seizures and other symptoms by gradually reducing the dose of gabapentin.

Don't stop taking gabapentin without talking to your doctor – you will need to reduce your dose gradually.

Will recreational drugs affect it?

Gabapentin can intensify the highs of recreational drugs like cannabis and heroin. So, if you use recreational drugs alongside gabapentin, there may be more chance of unpleasant side effects like panic attacks, anxiety and memory loss.

Can I drink alcohol with it?

Yes, you can drink alcohol with gabapentin. However, it may make you feel sleepy or tired.

During the first few days of taking gabapentin, it might be best to stop drinking alcohol until you see how the medicine affects you.

Will it affect my fertility?

Gabapentin does not reduce fertility in men or women.

Will it affect my contraception?

Gabapentin doesn't affect any type of contraception, including contraceptive pills and the morning after pill.

Can I drive or ride a bike?

You may feel sleepy, tired or dizzy when you first start taking gabapentin. This may also happen if your dose has increased. If this happens to you, don't drive or ride a bike until you feel more alert.

If you have epilepsy, you're not allowed to drive until you've had no seizures for 1 year, or if you only have seizures while you are asleep. You are also not allowed to drive if your epilepsy medicine has changed and for 6 months after.