Lamictal (Lamotrigine): Uses, Rash Warnings and Interactions

Uses and the product covered

Lamictal 100 mg is a standard oral lamotrigine tablet. Lamotrigine is used for specified epilepsy indications and maintenance or prevention of mood episodes in bipolar I disorder, with age and treatment-role differences between the cited UK and US labels. It is not an established acute treatment for a manic or depressive episode. This profile concerns the ordinary tablet, rather than Lamictal XR, and does not provide instructions for switching between tablet types.

Rash and other urgent warnings

Lamotrigine can cause life-threatening skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis. A new rash, blistering, peeling skin, mouth sores, fever or swollen glands needs immediate medical assessment. Early hypersensitivity can occur without an obvious rash. Follow the product warning to stop at the first rash unless a clinician determines it is clearly unrelated; do not restart treatment on your own. Severe inflammation, liver or blood problems and aseptic meningitis are additional recognised risks.

Interactions that change treatment

Valproate increases lamotrigine exposure and the risk of rash. Carbamazepine, phenytoin and some other enzyme-inducing medicines lower exposure. Oestrogen-containing contraceptives can reduce lamotrigine concentrations; starting, stopping or changing them, including the hormone-free interval, can alter levels and treatment response. Other oestrogen products, including hormone replacement therapy, also require review. These are reasons for an individual monitoring plan, not a reason to adjust doses independently. After a substantial treatment interruption, restarting the previous dose may be unsafe.

Everyday safety, heart disease and pregnancy

Dizziness, headache, nausea, blurred or double vision and poor coordination may affect driving or balance. The US label warns about potentially serious rhythm problems in people with certain structural or functional heart diseases or arrhythmias; a cardiac history should be discussed before treatment. Report worsening mood or suicidal thoughts promptly. Pregnancy can change lamotrigine concentrations, and levels may change again after birth. Discuss pregnancy planning and breastfeeding with the treating team; lamotrigine enters breast milk and an exposed infant may need monitoring. Do not abruptly change epilepsy treatment without professional advice.

Sources and scope

• Lamictal tablets and chewable/dispersible tablets - UK Summary of Product Characteristics - Text revised 5 November 2025; emc updated 19 November 2025
• Lamictal lamotrigine tablets - US prescribing information and Medication Guide - US label revised October 2025; DailyMed updated 10 October 2025

Source check: 30 October 2026. This records a source check, not a clinical review by a doctor or pharmacist. This summary does not replace the current leaflet supplied with your medicine or an individual treatment review.