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Drug Interaction — RACP Adult Medicine MCQ

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HardClinical PharmacologyDrug InteractionRACP Adult Medicine

A 45-year-old man on warfarin with an INR of 2.8 develops acute gout. He requires anti-inflammatory treatment. NSAIDs and colchicine are contraindicated. What is the safest option and what is an important interaction to consider?

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Correct answer: E — Prednisolone 25 mg daily – may potentiate warfarin effect (monitor INR closely)

Short-course oral prednisolone is the safest systemic option for gout when NSAIDs and colchicine are contraindicated. However, corticosteroids can potentiate the anticoagulant effect of warfarin through uncertain mechanisms (possibly affecting clotting factor synthesis). INR should be monitored more frequently (within 3–5 days) when prednisolone is commenced or ceased in a patient on warfarin. Intra-articular corticosteroid (option E) is ideal for monoarticular disease and avoids the systemic interaction.

Reference: AMH – 2025 – Corticosteroid-Warfarin Interaction; eTG – 2025 – Rheumatology