Adverse drug reactions and pharmacovigilance — branching viva

Opening (warm-up)

Examiner. A 7-year-old is admitted with a rash that began two weeks after starting lamotrigine. Take me through your first thought. [5]

Candidate. My first thought is that any new symptom with a temporal relationship to a newly started medicine puts an adverse drug reaction on the differential. Lamotrigine is an aromatic anticonvulsant with a well-recognised risk of cutaneous reactions, including rare Stevens-Johnson syndrome, and the two-week latency fits. So I would assess the child immediately, stop the lamotrigine, and characterise the rash to separate a benign exanthem from a severe cutaneous adverse reaction. [1]