A 48-year-old man with long-standing gout and multiple tophi has serum urate of 9.8 mg/dL despite allopurinol 600 mg/day. He has normal renal function (eGFR 72). What is the most appropriate next step?
- A Switch to febuxostat or add uricosuric agent (probenecid) ✓
- B Add colchicine indefinitely and continue allopurinol
- C Start pegloticase infusions immediately
- D Reduce allopurinol to 300 mg/day and reassess
Correct answer: A. Switch to febuxostat or add uricosuric agent (probenecid)
Explanation
When allopurinol at maximum tolerated/appropriate dose fails to achieve serum urate target (<6 mg/dL), switching to febuxostat (a non-purine XO inhibitor) or adding a uricosuric agent such as probenecid (in normal renal function) is the recommended next step. Pegloticase (IV pegylated uricase) is reserved for refractory tophaceous gout unresponsive to all oral ULT, not first-line after allopurinol failure. Reducing allopurinol would worsen control. Colchicine does not lower urate.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.