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Rheumatoid arthritis — SCE Rheumatology MCQ

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ModerateDisease-Modifying Antirheumatic DrugsRheumatoid arthritisSCE Rheumatology

A 34-year-old woman with rheumatoid arthritis has sustained low disease activity on leflunomide 20 mg daily. She wishes to attempt conception in approximately 4 months. A pregnancy-compatible alternative DMARD has been agreed, and she is using reliable contraception. Which strategy most appropriately manages leflunomide elimination before conception according to UK prescribing guidance?

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

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Correct answer: E — Stop leflunomide, give colestyramine 8 g three times daily for 11 days, document two A771726 levels below 0.02 mg/L at least 14 days apart, and wait 1.5 months from the first low level before conception

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

Leflunomide is unsuitable for pregnancy, and its active metabolite, A771726, may persist for a prolonged and unpredictable period because of enterohepatic recycling. Simply stopping treatment does not reliably achieve sufficiently low fetal exposure within this patient's desired timeframe. UK product information therefore permits accelerated elimination with colestyramine 8 g three times daily for 11 days. Clearance must then be verified by two A771726 concentrations below 0.02 mg/L obtained at least 14 days apart, with conception delayed until 1.5 months after the first qualifying result. A incorrectly applies an unverified fixed interval; three months does not replace accelerated elimination and biochemical confirmation in a woman planning pregnancy. B is inappropriate because leflunomide should be withdrawn and cleared before conception rather than continued until pregnancy is detected. C includes the correct washout regimen but one metabolite measurement is insufficient, and immediate conception omits the specified waiting interval. E resembles the alternative natural-elimination pathway, because concentrations may take approximately 2 years to fall, but UK prescribing information still requires two confirmatory measurements rather than assuming clearance. The pregnancy-compatible replacement DMARD should be established sufficiently early to maintain disease control while leflunomide is eliminated.

Reference: Guideline on prescribing drugs in pregnancy and breastfeeding Part 1: immunomodulatory anti-rheumatic drugs and corticosteroids (2022) — https://www.rheumatology.org.uk/guidelines/guidelines-details/pregnancy-and-breastfeeding-part-1 Leflunomide 20 mg film-coated tablets—Summary of Product Characteristics (14 November 2024) — https://www.medicines.org.uk/emc/product/5399/smpc