Carbamazepine

Medication name

Carbamazepine ("CAR-ba-MAZ-i-peen")
Brand name

Tegretol ("TEG-ri-tol")
Medication type

Mood stabiliser

Tablets*: 100mg, 200mg and 400mg strengths

Prolonged release tablets*: 200mg and 400mg

Liquids: 100mg in each 5ml spoonful

All commercially available products are now sugar-free.

*There are two different types of tablets for carbamazepine:

One type is slow release and must not be chewed or they will not give you the long-lasting effect (it should say 'prolonged release', 'SR', or 'slow release' on the box or label). You should swallow each tablet whole or break them in half along the line in the middle.
The second type of tablet are ordinary tablets, which again you should swallow whole. You can cut the tablet in half if it has a line in the middle of it. If you have difficulty swallowing tablets, rather than crush it, there are a number of liquid forms available.

If you are 18 or over, the doctor can prescribe carbamazepine for you as a licensed medicine for bipolar disorder (in people who don’t respond well to treatment with lithium).

It is also used to treat epilepsy and trigeminal neuralgia (intense facial pain).

If you are younger than 18, a specialist doctor may still consider this as a treatment option for bipolar disorder.

Other conditions carbamazepine can treat include:

depression (low mood)
some anxiety and panic disorders
alcohol withdrawal symptoms

In some cases, your doctor may recommend the use of genetic testing to help make a decision about whether this is the best treatment for you. The risk of severe side effects is higher if you are Asian and have a particular genetic variation. Checking this before stating treatment can help to weigh up the benefits and risks and decide if a different medicine would be better.

Your doctor will recommend you have a blood test before starting carbamazepine and while you are prescribed it. This is normal and it is important to check your liver and blood cells are okay and functioning normally while you are taking this medication.

Read our guide to bipolar disorder

About carbamazepine

Carbamazepine is a type of ‘mood stabiliser’. It controls feelings of excitability and over-activity. It can also help with periods of low mood.

Carbamazepine is usually only prescribed after you have already tried other mood stabilisers such as lithium.

Carbamazepine can help to calm down the brain. There are gateways in the brain called ‘sodium channels’, which can be open or closed. When they are open, there is more electrical activity in the brain. Carbamazepine locks on to closed sodium channels and keeps them closed. Reduced electrical activity leads to reduced release of chemical transmitters (neurotransmitters) that excite the brain, like glutamate, dopamine and noradrenaline.

It is still not fully understood how carbamazepine works to treat bipolar disorder, but the reduction in glutamate activity in the brain is thought to play an important part in this.

Carbamazepine and everyday life

You may start to feel some benefits after taking it for a few days. The effect will build over the first one to two weeks. It will take a few weeks at your normal dose for carbamazepine to show its full effects.

Your doctor will start you on a low dose, and then gradually increase it to the treatment dose that is right for you. This will reduce the chance of side effects.

Carbamazepine can cause weight gain or weight loss, but it is not possible to predict how this will affect you until you start taking it.

Talk to your doctor or pharmacist if you are concerned about your weight, or changes to your weight, while taking carbamazepine.

A common side effect of carbamazepine is a dry mouth. Over a long time, this can increase your risk of developing tooth decay or gum disease. Make sure you brush your teeth well and have regular dental check-ups. Speak to your dentist, doctor or pharmacist about things you can do to help.

You may want to let your family and friends know you are taking carbamazepine so they can support you and help you look out for side effects.

For guidance on this, check out our page on getting support with your medication.

You can feel very tired or drowsy in the first few days or week of taking carbamazepine. This should get better after the first week or two.

If you have been taking carbamazepine for more than a month and you continue to feel very tired, sleepy or struggle to function during the day, you should go back to your doctor and discuss what changes could be made to help. This may include switching to a different medication.

Alcohol

It may be possible to drink some alcohol in moderation while taking carbamazepine, but having the two together might make you very sleepy and unsteady on your feet.

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

Drinking alcohol every day, or in large amounts, can make your symptoms worse and may mean you won’t get the maximum benefit from your medication.

If you drink a lot of alcohol, it could increase the carbamazepine level in your body, and this could be dangerous.

Street drugs

Using both cannabis and carbamazepine at the same time might make you feel sleepier.

Cannabis and other drugs may have their own side effects on your mental health, like anxiety or psychosis.

Carbamazepine drives cocaine breakdown to make norcocaine. This chemical is more dangerous to your heart and liver than cocaine itself.
Carbamazepine can affect the levels of opioids in the body. You may need to take more of the drug to get the same effect as someone not taking carbamazepine, but this could be dangerous and lead to serious side effects.

If you are prescribed methadone or buprenorphine, carbamazepine reduces the level of these medicines in the body when they are used together, so if you stop carbamazepine the level might go up dangerously. Talk to your doctor about this before you stop carbamazepine.

There are many other street drugs, but we don’t know what effect taking them with carbamazepine will have, so it’s best to be cautious. There is no regulation of street drugs or ‘legal highs’, so even if there are no known issues with the medication you take, the supply you receive might be mixed with other substances that could be dangerous.

Get more advice on drugs and alcohol.

Many medicines, including some vitamins and herbal remedies, do not mix well with carbamazepine and the dose of some medicines will need to be adjusted.

Talk to your doctor about any medications you are taking before you begin treatment with carbamazepine.
Carbamazepine can affect how hormonal contraception works and can make it less effective at preventing pregnancy. Talk to your doctor about appropriate options for you.

Do not take carbamazepine if you are on or have taken MAOIs (drugs like phenelzine, isocarboxazid, tranylcypromine or moclobemide) in the last 14 days. You must wait until 14 clear days have passed before you can take carbamazepine.

Before you start taking carbamazepine, tell your doctor if you are taking any other medications including things you have bought from a pharmacy (or other shop) for common illnesses like colds and flu, and medications that you put on your skin.

Look at the leaflet inside your medicine box for more information about other medicines that can interact with carbamazepine. With some medicines your doctor may need to adjust the dose of your medicines if you take them together. Ask a doctor or pharmacist for more information if you have any questions.

Do not take carbamazepine tablets with grapefruit juice. Grapefruit juice may increase the absorption of carbamazepine from the gut and cause the levels of carbamazepine to increase.

There are multiple companies that manufacture this medicine and the non-active ingredients may vary between products and also between the different strengths of tablets that are available.

The carbamazepine liquid may contain sorbitol. Patients with hereditary fructose intolerance (HFI) should not take this medicinal product.

Sorbitol may cause gastrointestinal discomfort and a mild laxative effect. The liquid may also contain other excipients like Para hydroxybenzoates which may cause allergic reactions.

Always let your pharmacist know if you have any food allergies or intolerances, and always check with them if you’re concerned about any of the ingredients in your medication.

If you need to avoid animal products, please note that non-active ingredients used in the production of medicines may sometimes be of animal origin. Ask your pharmacist if you have any questions about the ingredients.

Further information about practical considerations for medicines if you need to avoid animal products can be found on the Vegan Society website.

Do not drive a car or ride a bike just after you start taking carbamazepine, or if the dose has just been increased.

Taking carbamazepine may make you feel sleepy or dizzy and may affect your eyesight when you start taking it, or after an increase in dose.
This could affect you if you drive a car, ride a bike, or do anything else that needs a lot of focus and coordination to do things safely. It might be best to stop doing these things for at least the first few days until you know how it affects you.

Most people drive as normal while taking carbamazepine. If you are worried about this or have any concerns you would like to discuss, speak to your doctor or pharmacist.

It is illegal to drive after taking medication if your ability to drive safely is impaired.

You must tell The DVLA (Driver and Vehicle Licensing Agency) if you have bipolar disorder, schizophrenia, schizoaffective disorder or other mental health conditions that could affect your driving.

You can be fined if you do not tell The DVLA about a medical condition that affects your driving and may be prosecuted if you are involved in an accident as a result.

Pregnancy

It is recommended that this medicine is not routinely prescribed during pregnancy because it can affect the development of the baby, but the risks and benefits should be discussed between you and your doctor.

If you become pregnant while you are on carbamazepine, you should carry on taking it and make an appointment to see your doctor as soon as possible. They can discuss the benefits and risks of continuing carbamazepine and help you to make a decision that is best for you and your baby. They may refer you to a specialist perinatal mental health team to support you with this decision. You can find out more information about taking carbamazepine during pregnancy at Bumps (Best Use of Medicines in Pregnancy).

If you are taking carbamazepine and planning to get pregnant, it is recommended that you take a higher dose of folic acid (5mg) while you are trying for a baby and during pregnancy.

Your dose of carbamazepine may need to increase later in pregnancy to keep the benefit.

Untreated mental illness, including bipolar disorder, can also be harmful to you and your developing baby, so decisions about stopping or avoiding medication when you are pregnant need to be discussed carefully with your doctor. If you and your doctor agree that carrying on with carbamazepine has more benefits than risks, you should tell your midwife that you are continuing to take this at your next appointment.

Post-natal

There are some other symptoms that can occur in new-born babies if carbamazepine is taken during pregnancy, so it is important to look out for these and get help if they happen. These include: sleepiness, difficulty feeding, being sick and having diarrhoea (loose poo). Some newborn babies have had seizures (fits) or breathing problems.

Your baby may need a vitamin K injection to help with healthy blood-clotting.

Your midwife can look out for this, monitor your baby for symptoms and provide support to you and your baby as needed.

Breastfeeding

Some carbamazepine is passed to the baby in breast milk, but only small amounts. If you breastfeed whilst taking this medication, it is important to look out for possible side effects in your baby like heavy sleeping, poor feeding or skin reactions.

Extra checks may be recommended for your baby to make sure their liver is healthy and to monitor their skin for any rashes. Always ask your midwife, health visitor, doctor or other healthcare professional if you have any concerns.

If your medication makes you sleepy, do not to sleep with your baby in the same bed, and be cautious when handling your baby (especially if waking during the night for feeds).

Talk to your doctor or midwife about the benefits and risks of breastfeeding while taking this medication to help you make the decision that is best for you and your baby.

Carbamazepine can have side effects that might affect your sex life, including:

swelling of the breasts and some milk flow (regardless of gender)
not wanting to have sex as much as usual, or at all
spotting and/or bleeding between periods
difficulty getting an erection (getting hard)

Most side effects occur when you first start medication and improve over time. If they do not, and this is a problem for you, make an appointment to discuss this with your doctor.

Untreated mental illness can have a negative effect on your sex life, so if carbamazepine helps you to recover, positive effects can include improving your desire, experience and enjoyment of sex as your mood lifts and you become interested in life and relationships again.

Fertility

There have been a few reports of lower sperm count and quality in people who are taking carbamazepine.

Carbamazepine can make hormone contraceptives like 'the pill' and implants less effective – you might need to change your contraceptive to avoid the risk of pregnancy.

Condoms and other barrier methods like the cap or diaphragm will not be affected by carbamazepine so you can use those safely while taking it.

Talk to your doctor about your carbamazepine if you are trying to get pregnant or planning a family.

Carbamazepine is not a banned substance in sport.

Most people play sports as normal while taking carbamazepine. It could, however, affect your concentration, co-ordination and eyesight.

If you play sports that need a lot of focus, you might want to stop for a short while when you start taking carbamazepine to see how it affects you.

If you are worried that taking carbamazepine might make doing the sports you enjoy more difficult, discuss this with your doctor.

Ideally it is best not to take carbamazepine for the first time just before your exams. You may feel dizzy, tired, restless or confused when you first take carbamazepine, and it could affect your eyesight.

You should talk to your doctor about any future exams if you are starting carbamazepine. You might decide together to delay starting it until you have done them.

If they are more than a week away, however, you might find that it is better to start carbamazepine to improve your motivation and ability to study.

Most people take exams as normal while taking carbamazepine. If you are worried that taking carbamazepine might make studying for or taking your exams harder, discuss this with your doctor.

Information and safety considerations

Your doctor will consider any other medical conditions or symptoms you have before recommending a medicine for you.

Your medicine will come with a ‘patient information leaflet’. It’s important that you read this information. Speak to your pharmacist if:

you’re not given a leaflet
you don’t understand the information
you need it in a different format or language
you’re concerned about something you’ve read

The information leaflet also includes a list of warnings and precautions to consider before you take the medicine. If you think that any of these apply to you and are concerned that your doctor is not already aware of them, check with your doctor or pharmacist before you start to take your medication (or as soon as possible if you are already taking it).

Uses, warnings, safety and side effects

Taking carbamazepine

Your doctor will advise you on how long it is best to keep taking your medication. This may vary depending on what you’re taking it for and how many times you’ve been unwell.

For bipolar disorder, you may need to continue with medicines long term because every time you become ill, there is more chance of you becoming ill again. Carbamazepine can be used as a long-term medicine, but there are other choices too, and lithium is still thought to be the best long-term medicine. You should discuss your options with your doctor.

Most people take carbamazepine for at least six months, but it may be beneficial to take it for a year or longer.

You and your doctor should talk about how long you need to take carbamazepine before you start your treatment.

You might have to change your dose to get the best effect for you.

You will get the best effect from this medicine if you take it regularly every day at the dose prescribed by your doctor.

You will probably start on a low dose and increase until it is right for you. You may have to take it more than once a day.

If you take your medication once a day, try and choose a time that you can always remember. This could be a mealtime, or when you brush your teeth. If it makes you feel sleepy, it may be best to take it just before bedtime. You can take it before or after food.

Different brands of carbamazepine tablets can release slightly different amounts of carbamazepine, even if they are the same strength. Ask your pharmacist to always give you the same brand of tablets. Keep the box to show them. This is more important if you are taking carbamazepine to prevent seizures and fits.

If you forget to take a dose, take it as soon as possible unless it is less than four to six hours until your next dose.

If you forget to take it by the time of the next dose, just take the next dose. Do not try and catch up by taking a double dose.

If you forget to take your tablets for a few days, you may start getting your old symptoms back. Talk to your doctor if this happens. You may need to restart the carbamazepine slowly or find a different treatment.

Once you start taking carbamazepine, the brain adjusts to the new balance of chemicals. If you stop taking the carbamazepine all at once, the balance starts to change again. You could get your old symptoms back.

There is a risk that you may get seizures or fits. This is because even if you are not taking the carbamazepine for epilepsy, your body has got used to having an anticonvulsant medication on board.

When you decide with your doctor to stop taking carbamazepine, you will probably reduce the dose slowly over at least a month to stop you getting any uncomfortable withdrawal symptoms.

Go and speak to your doctor if you have missed a few doses or have decided to stop taking your medication.

Warnings and safety

If you have taken more than the dose prescribed by your doctor, contact NHS 111 immediately to ask for advice, or ask a family member or friend to do this for you. This is important even if you don’t feel any different.

NHS 111 can give you advice and direct you to the best place to get more help if you need it.

If you have taken too much medication on purpose, or if after taking this you quickly feel unwell, call 999 or get someone to take you to A&E straight away. This includes any of the following signs:

feeling sleepy or confused
slurring when you speak
feeling agitated or sensing things that are not there
unusual movements that you cannot control
having seizures (fits)
your breathing going very slow
fast heartbeat, and a possible heart attack
being sick
blurred eyesight
finding it hard to go for a wee

If you need to go to A&E, do not travel alone or drive yourself there. Get your parent, family member or friend to go with you to support you and keep you safe on the way. If someone is not able to drive you there, call for an ambulance. Take your medication with you and tell doctors how much you have taken.

Suicidal thoughts

Symptoms of bipolar disorder can sometimes cause you to have thoughts about hurting yourself or taking your own life. While uncommon, this could also be a side effect of your medicine. This can happen to anyone including people under 18.

If you have any thoughts like this, it is important you get urgent help. Contact your doctor immediately for advice and support. This could be your GP or specialist mental health team. If you are able, share how you are feeling with family member or friend as well so they can support you to get help.

If you discussed with your doctor what to do if you get these thoughts and created a safety plan, read this to remind you who to contact for support and what you can do to help you cope.

Read our guide to suicidal feelings

Serious side effects

Carbamazepine can cause serious side effects, including allergic reactions.

Stop taking carbamazepine and go to a doctor or hospital straight away if you get any of the following symptoms:

serious skin reactions such as rash, red skin, blistering of the lips, eyes or mouth, or genitals, or skin peeling with a fever (these reactions may be more frequent in patients of Chinese or Thai origin)
pain in your joints and muscles, a rash across the bridge of the nose and cheeks, and problems with your breathing (these may be the signs of a rare reaction known as systemic lupus erythematosus (SLE))
fever, skin rash and joint pain
wheezing and coughing, difficulty breathing, feeling faint, rash, itching or facial swelling (these may be the signs of a severe allergic reaction)
severe stomach pain

If you get a rash just after starting to take carbamazepine, or after restarting it after a treatment break, you must stop the tablets and see a doctor straight away, especially if you are from a Han Chinese or Thai family. You may also get a fever, headache and body ache, like having flu, and then ulcers in your mouth and all over your body.

Get your parent, family member or friend to take you or go with you to support you and keep you safe on the way. If someone is not able to drive you there, call for an ambulance. Take your medication with you.

Contact your doctor immediately if you get any of the following symptoms:

mouth ulcers or unexplained bruising or bleeding
sore throat or high temperature, or both
jaundice (yellowing of your skin or the whites of your eyes)
swollen ankles, feet or lower legs
anxiety or confusion
you have a fall because of feeling dizzy, drowsy or confused

If you are unable to contact your doctor, call NHS 111 for urgent advice.

Side effects and your health

Side effects are more common when you first start taking carbamazepine. Many go away as you continue your medicine. If they don’t get better, or if you are worried by them and they are causing you distress, speak to your doctor or pharmacist about them.

Very common side effects of taking carbamazepine (affecting more than one in ten people) include:

dizziness and tiredness
feeling unsteady or finding it difficult to control your movements
feeling or being sick
skin reactions (this can be serious – see the less common side effects below)
leucopoenia (a reduced number of the cells which fight infection making it easier to catch infections – your doctor will need to take a blood test to check for this, but you may get symptoms like a sore throat, flu-like symptoms or mouth ulcers)

Common side effects of taking carbamazepine (affecting up to one in ten people) include:

changes in the blood making you more likely to bruise or bleed
fluid retention and swelling
weight increase
low sodium in the blood which might result in confusion
headache
double or blurred vision
dry mouth
loss of appetite

There are other side effects that you can get when taking this medicine. We have only included the most common ones here.

This list of side effects can look scary. You may not experience any of them, but it’s important to be aware of them so you know what to do if they do happen.

Unless your side effects are very severe or distressing, try to continue taking your medication until you can talk to your doctor. Your doctor can make changes to your medication to help if needed.

An uncommon but important side effect to be aware of is thoughts of harming yourself, thinking about taking your own life or trying to take your own life. This may be a symptom of your illness, including depression, but may be a side effect of medication. If you experience these thoughts, contact your doctor to seek immediate support to keep you safe.

Rarely, some side effects that appear as a rash can be serious. If you get a red or purple rash that spreads all over your body and forms blisters as well as flushing or flu-like symptoms, stop taking carbamazepine and seek immediate medical help.

Your doctor will make sure you are monitored carefully for these side effects, and you should decide with your doctor what to do if you experience these feelings while taking carbamazepine. It’s a good idea to write these plans down and keep them somewhere safe.

If you are taking carbamazepine and have not talked about this with your doctor, go back to them and talk it through. You might also want to talk to your parents, family member or friend about it too.

Before starting carbamazepine, your doctor will check that your blood, liver and kidneys are healthy and functioning normally. This will require a blood test.

Your doctor will recommend regular monitoring while you are taking carbamazepine (for example after six months and then once a year).

It is very important to go for these checks when you are asked to do so. If you are worried or anxious about the monitoring, talk to your doctor, care team or practice nurse about this for advice and support.