skip to main content

Mepacrine in Lupus — SCE Rheumatology MCQ

Instant feedback + full explanation. One question, done properly.

ModerateRheumatology PharmacologyMepacrine in LupusSCE Rheumatology

A 40-year-old woman with systemic lupus erythematosus has persistent active cutaneous disease despite photoprotection, appropriate topical treatment and adherent hydroxychloroquine therapy at 5 mg/kg/day actual body weight. Mepacrine is being considered. Which statement best describes its pharmacological role in this situation?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — It is an antimalarial that may be added to hydroxychloroquine for refractory cutaneous lupus without adding hydroxychloroquine-type retinal toxicity.

Mepacrine, also called quinacrine, is an antimalarial with immunomodulatory activity. It may be used by specialist services as an adjunct to hydroxychloroquine when cutaneous lupus remains active despite adequate dosing, adherence, photoprotection and topical therapy. Published series and reviews support additional cutaneous benefit from the combination. Unlike hydroxychloroquine and chloroquine, mepacrine is not associated with their characteristic retinal toxicity, so adding it does not require increasing hydroxychloroquine exposure. It is neither a corticosteroid nor a biologic, and combination antimalarial therapy is not inherently contraindicated. Important adverse effects include yellow discoloration of the skin and gastrointestinal intolerance; serious haematological toxicity is rare. Availability may limit its use in UK practice.

Reference: Teboul A, Arnaud L, Chasset F. Recent findings about antimalarials in cutaneous lupus erythematosus: What dermatologists should know. Journal of Dermatology. 2024;51:895–903. https://pubmed.ncbi.nlm.nih.gov/38482997/