Lamotrigine
Mood stabiliser
Indications
Bipolar depression — preventionEpilepsy
Adult dose
Slow titration: 25 mg OD weeks 1–2, 50 mg OD weeks 3–4, 100 mg OD week 5, 200 mg OD week 6. Halve doses if on valproate; double if on enzyme inducer.
Common side effects
HeadacheRash (early)DizzinessDiplopiaNausea
Serious side effects
Stevens-Johnson syndrome / TEN (rapid titration → higher risk)DRESSAseptic meningitisHaemophagocytic lymphohistiocytosis
Contraindications
Previous severe rash on lamotrigine
Monitoring
- Counsel re: rash — stop and seek urgent review if any rash in first 8 weeks
Notable interactions
- Valproate — doubles lamotrigine levels (halve dose, slow titration)
- Carbamazepine, phenytoin, rifampicin — halve levels
- Combined oral contraceptive lowers levels by ~50%
Curated reference based on BNF, Maudsley Prescribing Guidelines and NICE. Verify against current BNF and local guidelines before prescribing.