For epilepsy and trigeminal neuralgia · Written by the Lyng Pharmacy team, based on NHS and BNF guidance · Updated August 2026
Also sold asTegretol
Type of medicineAntiepileptic
Available asTablets, modified-release tablets, liquid, suppositories
How you get itPrescription only
Carbamazepine treats epilepsy and is the first-line treatment for trigeminal neuralgia. It is a powerful enzyme inducer, which means it speeds up the breakdown of a long list of other medicines — including contraception.
How to take it
Usually twice daily, with or after food. Modified-release tablets are swallowed whole.
Doses are built up gradually to reduce dizziness and drowsiness. Never stop suddenly — in epilepsy this can trigger seizures.
Stay on the same brand where possible; switching is generally avoided in epilepsy.
Interactions — the big one
Carbamazepine reduces the effectiveness of hormonal contraception, including the combined pill, progestogen-only pill, patch, ring and implant. Alternative contraception such as the copper coil or an injection is usually needed — discuss this before starting.
It also lowers levels of warfarin, DOACs, some antidepressants, statins, corticosteroids, some HIV medicines and many others. Tell every prescriber and pharmacist that you take it, and check before starting anything new including over-the-counter and herbal products.
Grapefruit juice raises carbamazepine levels and is best avoided.
What to report
Any rash, particularly with fever, ulcers or blistering — stop and seek help immediately. Serious skin reactions are more common in people of Han Chinese, Thai and some other Asian backgrounds, who may be tested for the HLA-B*1502 gene before starting
Sore throat, fever, mouth ulcers, unexplained bruising or bleeding — possible blood disorder
Yellowing of the eyes or skin
Confusion, unsteadiness or worsening seizures
Blood tests check full blood count, liver function and sodium. Low sodium is a recognised effect — report headache, confusion, nausea or unusual drowsiness.
Carbamazepine carries risks in pregnancy; discuss plans with your specialist well in advance, and take folic acid if advised.
Always read the label. This page is general information, not advice for your situation. Doses, warnings and interactions differ between products and between people. Check the leaflet inside your medicine, and ask our pharmacist if anything is unclear — that conversation is free and takes two minutes.
Questions about Carbamazepine?
1 Lyng Lane, West Bromwich B70 7RW · Mon–Fri 8:30am–6pm, Sat 9am–1pm · 0121 500 5756
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