Gabapentin is used to treat epilepsy.
Occasionally, gabapentin is used to treat migraine headaches.
Gabapentin is available on prescription as capsules, tablets, and a liquid that you drink.
- 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.
- It takes at least a few weeks for gabapentin to work.
- You don't have to have epilepsy for gabapentin to help with pain or migraine.
- The most common brand name is Neurontin.
Who can take gabapentin
Gabapentin can be taken by adults and children aged 6 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 another medicine
- have kidney problems
- have ever abused or been addicted to a medicine
- are trying to get pregnant, are already pregnant or are breastfeeding
How and when to take
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 is likely that once your illness is under control you will still need to take gabapentin for many years.
If you have nerve pain, it is 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 often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways that are suitable for you and your medicines.
What if I take too much?
Taking too much gabapentin by accident may cause unpleasant side effects. These include feeling dizzy or sleepy, seeing double, slurring your words, diarrhoea and passing out.
If this happens, call your doctor straight away, or go to the nearest hospital accident and emergency (A&E) department.
If you can, take the box or leaflet inside the packet plus any remaining medicine with you to the hospital.
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 are usually mild and go away by themselves. If you experience these side effects, keep taking the medicine, but tell your doctor if they bother you or don't go away:
- tiredness or feeling sleepy
- dizziness or losing your co-ordination
- feeling sick 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 notice 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
The warning signs of a serious allergic reaction are:
- an itchy red rash
- tightness in the chest or throat
- having trouble breathing or talking
- swelling of the mouth, face, lips, tongue or throat
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.
How to cope with side effects
What to do about:
- feeling sleepy, tired or dizzy – don't drive or use tools or machinery if you are feeling this way. 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 – take gabapentin with or after a meal or snack. It may also help if you don't eat rich or spicy food.
- diarrhoea and vomiting – have small but frequent sips of water if you have diarrhoea or you are vomiting. 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.
- constipation - eat more high-fibre foods such as fresh fruit and vegetables and cereals, and try to drink several glasses of water or other fluid each day. It may also help to exercise more regularly, for example, by going for a daily walk or run.
- 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.
- a dry mouth – chew sugar-free gum or suck sugar-free sweets.
You can report any suspected side effect to a UK safety scheme.
Pregnancy and breastfeeding
Gabapentin is not generally recommended in pregnancy. There is no firm evidence that it's harmful to an unborn baby but for safety women are usually advised to take it in pregnancy only if the benefits of the medicine outweigh the potential harm.
If you take gabapentin for epilepsy and become pregnant, do not 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.
Women who are trying to get pregnant or have become pregnant are 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
Tiny amounts of gabapentin get into breast milk but generally, you can breastfeed as normal while taking it.
Check with your doctor first if your baby is premature or has kidney problems.
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, speak to your pharmacist before taking gabapentin if you routinely take any herbal or alternative remedies.
How does gabapentin work?
When will I feel better?
Can I get addicted to gabapentin?
Can I get epilepsy medicines for free?
Are there similar medicines to gabapentin?
Should I stick to the same brand of gabapentin?
Is it safe to take it for a long time?
What will happen when I come off it?
Will recreational drugs affect it?
Can I drink alcohol with it?
Will it affect my fertility?
Will it affect my contraception?
Can I drive or ride a bike?