MTX Pancytopenia Emergency — SCE Rheumatology MCQ

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HardRheumatology EmergenciesMTX Pancytopenia EmergencySCE Rheumatology

A 50-year-old woman with RA on Methotrexate 20 mg weekly develops pancytopenia (Hb 72 g/L WCC 1.8 neutrophils 0.4 platelets 38). She has been feeling unwell for 1 week with sore throat and mouth ulcers. What immediate actions are required?

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Correct answer: D — Stop Methotrexate immediately administer IV Folinic acid (not folic acid) treat as neutropenic sepsis with empiric IV antibiotics and arrange urgent haematology review

Methotrexate-induced pancytopenia is a medical emergency. Immediate management includes: stop Methotrexate administer IV Folinic acid (Calcium folinate NOT folic acid as Folinic acid directly bypasses the folate block) start empiric IV broad-spectrum antibiotics (neutropenic sepsis protocol given febrile neutropenia risk) arrange urgent haematology review and consider G-CSF for severe neutropenia. Risk factors for Methotrexate myelotoxicity include renal impairment (reduced clearance) folate deficiency concomitant Trimethoprim (NEVER co-prescribe with Methotrexate) and drug interactions (PPIs NSAIDs at high doses). BSR 2025 csDMARD guidelines specify that Trimethoprim and Co-trimoxazole should be recorded as allergies to prevent inadvertent co-prescribing.

Reference: BSR 2025 csDMARD guidelines; BNF Folinic acid rescue