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Rheumatoid arthritis — SCE Rheumatology MCQ

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ModeratePharmacologyRheumatoid arthritisSCE Rheumatology

A 34-year-old woman with rheumatoid arthritis has stable low disease activity on leflunomide 20 mg daily. Pregnancy-compatible disease-modifying therapy has been arranged, and she wishes to attempt conception as soon as the licensed leflunomide elimination procedure permits. Her pregnancy test is negative, and she currently uses a combined oral contraceptive. Which preconception plan is most appropriate?

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

Reveal the answer and explanation

Correct answer: E — Stop leflunomide; use non-oral contraception; give colestyramine 8 g three times daily for 11 days; obtain two A771726 levels <0.02 mg/L ≥14 days apart; wait 1.5 months from the first low level.

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

Leflunomide must be stopped before planned conception because its active metabolite, A771726, is suspected to cause serious birth defects and persists through enterohepatic recycling. The licensed accelerated elimination regimen is colestyramine 8 g three times daily for 11 days; activated powdered charcoal 50 g four times daily for 11 days is an alternative. Clearance requires two A771726 concentrations below 0.02 mg/L, sampled at least 14 days apart. Fertilisation must be deferred until 1.5 months after the first concentration below this threshold. Because colestyramine may impair absorption of oestrogens and progestogens, an alternative to oral contraception is required during washout. B is incorrect because a single low concentration does not verify clearance, and 14 days is not the specified post-threshold interval. C has the correct elimination and testing schedule, but oral contraceptive reliability cannot be guaranteed during washout; it also substitutes the second result for the specified 1.5-month interval from the first low result. D is inappropriate because, without accelerated elimination, A771726 may remain above the threshold for about 2 years rather than 3 months. E applies an insufficient colestyramine dose for the licensed leflunomide washout procedure; the reduced 4 g three-times-daily alternative appears in teriflunomide product information, not this leflunomide SmPC.

Reference: Leflunomide 10 mg film-coated tablets — Summary of Product Characteristics (27 July 2026) — https://www.medicines.org.uk/emc/product/101936/smpc Leflunomide Specific Patient Information (Approved July 2026) — https://www.medicines.org.uk/emc/rmm/107108/Document