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Leflunomide toxicity — SCE Rheumatology MCQ

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HardRheumatological PharmacologyLeflunomide toxicitySCE Rheumatology

A 36-year-old woman with rheumatoid arthritis stopped leflunomide 3 weeks ago after deciding to try for pregnancy. She took the drug for 18 months and has active synovitis controlled by local steroid injections. Her partner asks whether conception can proceed now. Pregnancy testing is negative. What is the most appropriate management?

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

Reveal the answer and explanation

Correct answer: A — Cholestyramine washout before conception

Explanation lettering: B = shown as A · D = shown as B · A = shown as C · E = shown as D · C = shown as E

Give cholestyramine washout and confirm low leflunomide level is best because leflunomide has prolonged enterohepatic recirculation and requires a washout procedure with confirmation of low teriflunomide levels before conception. A is less suitable because restarting leflunomide maintains teratogenic exposure; C is less suitable because methotrexate is teratogenic and contraindicated when planning pregnancy; D is less suitable because rituximab is not a fertility-planning substitute for leflunomide washout; E is less suitable because 4 weeks is inadequate because drug persistence may be much longer. Clinical pearl: pregnancy questions often hinge on drug persistence rather than the last tablet date.

Reference: https://www.nice.org.uk/guidance/conditions-and-diseases/musculoskeletal-conditions