Lamotrigine — consultant viva

Station structure

Time: 8–10 minutes. Depth: consultant teaching registrar. Expect named trials, product-table titration logic, and automatic SCAR stop rules without inventing exact national tablet strengths as universal law.[1][7][10]

Core questions and model points

1. Where does lamotrigine sit in bipolar care? Depression-pole maintenance and modest acute bipolar depression effect; not acute antimanic monotherapy. Name Bowden/Calabrese 18-month trials and Goodwin pooled polarity message; Geddes meta for acute depression magnitude.[1][2][3][4][10]

2. How do you titrate safely in monotherapy? Start low (classic 25 mg daily × 2 weeks → 50 mg daily × 2 weeks → stepwise to individualised target often ~200 mg/day). Slow titration is the rash-risk intervention. Cite dosing guideline culture (Messenheimer/Guberman).[7][9]

3. What changes with valproate? Valproate inhibits LTG metabolism (Yuen) → use slower/lower co-therapy table. Classic fail is monotherapy schedule on VPA.[5][9]

4. What about combined OCPs? Reduce LTG levels; counsel on start and stop of ethinylestradiol-containing contraception; adjust dose/monitor efficacy and toxicity accordingly (Sabers/Christensen/Sidhu lineage).[6]

5. Day-12 fever and oral erosions? Stop lamotrigine immediately; SJS/TEN pathway; no push-through titration; document future contraindication to casual rechallenge.[7]

6. Missed 10 days at 200 mg? Re-titrate from low dose per product guidance — do not resume 200 mg abruptly.[9]

7. Pregnancy counselling? EURAP comparative malformations: LTG more favourable than valproate, not zero risk; level changes across pregnancy/postpartum; perinatal partnership; valproate hierarchy if pregnancy possible.[8]

Examiner traps

• Calling LTG first-line acute mania treatment.[1]
• Ignoring valproate or OCP interactions.[5][6]
• Watching mucosal rash while continuing the drug.[7]
• Claiming absolute teratogenic safety.[8]