A 55-year-old man with long-standing tophaceous gout has serum urate of 10.8 mg/dL despite maximum tolerated allopurinol (600 mg/day). He has normal renal function and no contraindications. What is the NEXT appropriate step in urate-lowering therapy?
- A Increase allopurinol to 900 mg/day
- B Switch to or add febuxostat ✓
- C Add rasburicase
- D Administer pegloticase monthly injections as first rescue
Correct answer: B. Switch to or add febuxostat
Explanation
Febuxostat is a non-purine xanthine oxidase inhibitor that can be used when allopurinol fails or is not tolerated; it effectively lowers urate in patients refractory to maximum-dose allopurinol. Allopurinol above 800-900 mg/day is rarely used in practice and increases toxicity risk. Rasburicase is used for tumour lysis syndrome, not chronic gout. Pegloticase (recombinant pegylated uricase) is reserved for severe refractory tophaceous gout after failure of conventional urate-lowering agents, not a step before febuxostat trial.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.