Carbamazepine is used to control some types of seizures, as a mood stabilizer and for trigeminal neuralgia. Learn how to use the medication, its common side effects, special precautions to watch out for, and more.

What is this medication for? 

Carbamazepine is used to control some types of seizures (commonly known as fits). It can also be used as a mood stabilizer to help reduce mood swings in a condition known as bipolar disorder. It is used in other medical conditions such as trigeminal neuralgia, where a patient experiences nerve pain at the face area.

How should I take/use this medication?

Follow the instructions on your medication label and take the medication as prescribed by your doctor. To reduce stomach upset, you can take this medication after food.

If you are taking the controlled-release tablet, swallow the tablet whole or halved, do not chew or crush. These tablets are specially designed to release the medication slowly over a period of time.

If you are using oral liquid form/suspension, shake the bottle well before using. Use a medicine spoon or graduated syringe provided to measure your medication. Do not use household spoons as they may not be accurate.

You may not experience any benefit immediately after starting the medication as it may take up to a few weeks before this medication can work fully. You should continue to take your medication regularly as instructed by your doctor even if you feel well. Stopping your medication without informing your healthcare professionals may cause your condition to worsen quickly.

Do not stop taking or adjust the dose of this medication without consulting your healthcare professionals. Do not change brands or formulations of the medication without informing your healthcare professional.

What should I do if I forget to take/use this medication?

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for your next dose, take only the usual dose. Do not double your dose or use extra medicine to make up for the missed dose.

What precautions should I take?

According to the Health Science Authority (HSA) regulation, it is compulsory for all Asian patients who are first prescribed with carbamazepine to be tested for the specific gene (HLA-B*1502) that could result in higher risk of Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TENS). SJS and TEN are rare and serious skin reactions which can happen after using some medications. 

Symptoms include mouth ulcers, face swelling, blisters on skin, skin rashes that spread throughout the body within hours to days after the medication. It usually occurs within the first few months (monitor closely for the first 3 months) of treatment. Those who have been taking carbamazepine for more than 3 months without developing skin reactions are at low risk of SJS or TEN.

Inform your healthcare professionals if you have the following medical conditions before starting on carbamazepine:

• Liver problems
• Kidney problems
• Heart problems
• Blood related diseases
• Drug allergies 

For female patients of child-bearing age: Discuss with your doctor regarding family planning if you will be starting or currently taking carbamazepine. 

Consult your healthcare professional immediately if your seizures get worse or become different after you start on this medication.

What are some common side effects of this medication?

Like all medicines, this medication may cause some possible side effects but not everyone experiences them. Consult your healthcare professional if any of the side effects lasts more than a few days or become severe and bothersome.

The common side effects of carbamazepine include:

• Dizziness, feeling lightheaded
  • Get up slowly from a sitting or lying down position
• Drowsiness
  • Avoid driving, operating machinery or doing physical activities that require great efforts
  • Avoid taking over-the-counter medications (such as cold or allergy medications) that could also add on to the drowsiness, refer to a healthcare professional if needed
• Hard Stools (Constipation)
  • Increase consumption of foods which are high in fibre such as fruits and vegetables, and ensure you are drinking sufficient fluid (i.e. 8 glasses or 2 litres of water daily)
  • Increasing daily activity may also help to improve constipation
• Loose stools (Diarrhoea)
  • While experiencing diarrhoea, you should maintain your nutrition by eating easy to digest foods such as soups and ensure you are drinking sufficient fluid
  • Drink plenty of fluid (at least 2 litres) every day when you are having diarrhoea.
  • Inform doctor if diarrhoea is severe and does not improve with medications.
  • Avoid spicy and/or fried food, alcohol, coffee, tea, milk and dairy products.
• Nausea, vomiting
  • Take the medicine with or after food to reduce nausea and vomiting
  • Avoid food that is too rich, spicy or has strong smells
  • Take small and frequent meals, rather than 3 large meals
  • Do not take the medication with carbonated drinks
• Loss of appetite, stomach upset
  •  Take the medicine with or after food
• Headache, back pain
  • Use paracetamol, if necessary, to relieve headache or back pain

What are some rare but serious side effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following:

• Swollen face / eyes/ lips / tongue
• Difficulty in breathing
• Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

If the following serious side effects happen, you should consult your healthcare professionals immediately:

• Blistering, peeling, red skin rash due to Stevens-Johnson syndrome (SJS) and Toxic epidermal necrolysis (TEN)
  • SJS is a rare and serious skin reaction. Symptoms include face swelling, blisters on skin, skin rashes that spread within hours to days. 
  • TEN is a more severe form of skin reaction. Symptoms include fever and flu-like symptoms, blisters on skin, skin rashes that spread within hours to days. Areas such as the mouth, eyes, genitals are commonly involved.
  • It usually occurs within the first few months (monitor closely for the first 3 months) of treatment.
  • As SJS and TEN progress rapidly, please consult healthcare professionals if you show first sign of rash.
• Fever, chills, sore throat, mouth ulcers or sores
• Unusual bruising or bleeding
• Chest pain or a fast, pounding or irregular heartbeat
• Changes in how much and how often you urinate
• Liver problems: Dark coloured urine or light-coloured stools, yellowing of your eyes or skin, severe loss of appetite, stomach pain, nausea, vomiting that does not go away
• Blurred vision or double vision
• Feeling clumsy, unsteady movements

In rare cases, this medication may cause the following changes to a person’s mental condition, especially in the first few weeks of treatment or during dose changes:

• Worsening agitation, restlessness, violent behaviour, or
• New or worsening thoughts of harming yourself or ending your life
• Other changes in mood or behaviour

Please inform your doctor as soon as possible, or for your family or caregiver to inform your doctor if you are unable to seek treatment on your own. 

Do not stop taking this medication on your own without discussing with your doctor. 

It is important to note that your doctor has prescribed this medication as he/ she feels you will benefit more from taking this medication over the possible risks that it may cause, which have a low chance of occurring, and most people take this medication without any of such problems.

What food or medication should I avoid when I take/use this medication?

Inform your healthcare professional that you are on carbamazepine. Carbamazepine may decrease the effectiveness of hormonal contraceptives such as birth control pills, patches, rings, injections, implants or intrauterine devices, that prevent pregnancy. Discuss with your healthcare professionals regarding birth control while on carbamazepine.

Antibiotics such as erythromycin and clarithromycin should not be taken with carbamazepine. Combination of these medications can increase the risk of experiencing side effects of carbamazepine and reduce effectiveness of the antibiotics. 

Avoid eating grapefruit or drinking grapefruit juice while you are on carbamazepine as it can increase the risk of experiencing side effects of carbamazepine. 

Please consult your healthcare professionals before using any other medications, including over-the-counter medicines, supplements and herbal products as some of these may affect the medication in your body.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How should I throw this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing it into the rubbish chute or bin.

Disclaimers

Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on May 2024