carbamazepine at a glance
Medicine class
Anti-seizure medicine; a carboxamide sodium-channel blocker.
Licensed roles
Partial and generalised tonic-clonic seizures, trigeminal neuralgia, and prevention of manic-depressive illness when lithium is ineffective.
Food
Oral formulations can generally be taken with or without food.
Product continuity
For epilepsy, changing manufacturer or formulation should be clinically managed because exposure can vary.
What is carbamazepine used for?
Selected UK products are licensed for:
Partial seizures and generalised tonic-clonic seizures. Carbamazepine is generally unsuitable for absence or myoclonic seizures and may aggravate atypical absences.
Pain caused by trigeminal neuralgia.
Prevention of manic-depressive illness when lithium has not worked.
Suppositories are licensed only as temporary replacement treatment for epilepsy when oral administration is not possible.
How does carbamazepine work?
Carbamazepine blocks voltage-sensitive sodium channels, particularly in repeatedly firing nerve cells. This stabilises overactive nerve membranes and limits repeated electrical discharges and their spread.
carbamazepine preparations and strengths
Modified-release tablet
Route: Oral
Strengths: 200 mg, 400 mg
Oral suspension
Route: Oral
Strengths: 100 mg/5 mL
Tablet
Route: Oral
Strengths: 100 mg, 200 mg, 400 mg
How to take carbamazepine
Follow the label and use the same preparation unless a prescriber or pharmacist manages a change. Sudden withdrawal can cause seizures to recur.
Swallow standard tablets with water.
Shake oral suspension well and measure it with the supplied oral syringe or medicine spoon, not a kitchen teaspoon.
Do not chew prolonged-release tablets; swallow the prescribed whole or divided tablet with liquid.
Chew Chewtabs before swallowing and use liquid to wash down remnants.
Suppositories are for rectal use and must never be swallowed.
Avoid grapefruit and grapefruit juice because they can increase carbamazepine exposure and side effects.
carbamazepine side effects
Common or expected effects
- Dizziness, sleepiness or tiredness
- Nausea or vomiting
- Dry mouth or headache
- Blurred or double vision
- Unsteadiness or changes in coordination, balance or speech
Get urgent medical advice
- Severe, painful or blistering rash, peeling skin or mouth ulcers
- Facial or throat swelling, wheezing or breathing difficulty
- Fever, sore throat, infections, unexplained bruising or bleeding
- Yellow skin or eyes, dark urine or other signs of liver injury
- Marked confusion, weakness, worsening seizures or other symptoms of low blood sodium
- Major mood changes or suicidal thoughts
carbamazepine in pregnancy
Exposure during pregnancy is associated with an increased risk of congenital abnormalities, but uncontrolled epilepsy can also seriously harm the pregnant person and baby. Obtain prompt specialist review when planning pregnancy or after becoming pregnant, and do not stop carbamazepine without medical advice. It can reduce the effectiveness of some hormonal contraception, which should be reviewed with a clinician or pharmacist.
carbamazepine while breastfeeding
Carbamazepine can often be used during breastfeeding when the infant is healthy and benefits outweigh risks. It passes into breast milk; seek clinical advice if the infant is unusually sleepy, feeds poorly, develops a rash, has dark urine or pale stools, or becomes jaundiced.
carbamazepine interactions
Carbamazepine strongly induces liver enzymes and is mainly metabolised through CYP3A4, so it affects and is affected by many medicines.
Hormonal contraceptives and hormone replacement therapy
Carbamazepine can reduce hormone exposure and contraceptive effectiveness.
Warfarin and direct-acting oral anticoagulants
It may reduce anticoagulant exposure and effectiveness, requiring specialist review and monitoring.
Common questions about carbamazepine
Answers are fully visible for fast scanning and source review.
Can carbamazepine cause a serious rash?
Rarely, it can cause severe skin reactions. A painful, blistering or peeling rash, especially with mouth sores, fever or breathing difficulty, needs emergency assessment.
Can I switch brands or formulations?
Do not switch without professional advice, particularly for epilepsy. Exposure can differ and affect seizure control or adverse effects.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.