Carbamazepine

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.

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.