First‑Line Urate‑Lowering Therapy for Gout: Allopurinol Recommendations

First‑Line Agent Selection

The American College of Rheumatology (2020) strongly recommends allopurinol as the preferred first‑line urate‑lowering therapy for all patients with gout, including those with chronic kidney disease (CKD) stage ≥ 3 (moderate‑quality evidence). 1
Xanthine oxidase inhibitors (allopurinol or febuxostat) are strongly preferred over probenecid for patients with moderate‑to‑severe CKD (stage ≥ 3). 1

Start allopurinol at ≤ 100 mg/day (≤ 50 mg/day in patients with CKD stage ≥ 3) and titrate every 2–4 weeks. This “start low, go slow” strategy is strongly recommended to minimize the risk of allopurinol hypersensitivity syndrome and gout flares. (moderate‑quality evidence) 1
Increase the dose by 100 mg increments every 2–4 weeks until serum urate falls below 6 mg/dL (or below 5 mg/dL when tophi are present). 1

Begin colchicine prophylaxis (0.6 mg once or twice daily) concurrently with allopurinol and continue for at least 6 months, or for 3 months after the serum urate target is reached when no tophi are present. This prophylaxis is strongly recommended to prevent acute gout flares triggered by urate mobilization. (moderate‑quality evidence) 1

Probenecid may be initiated at 500 mg once or twice daily with dose titration as needed, but only after xanthine oxidase inhibitors are ineffective, not tolerated, or contraindicated. 1
Probenecid is strongly recommended against in patients with moderate‑to‑severe CKD (stage ≥ 3); xanthine oxidase inhibitors remain the preferred agents. 1
Absolute contraindications for probenecid include a history of nephrolithiasis or uric‑acid kidney stones. 1

Severe allopurinol hypersensitivity syndrome (AHS) is an absolute contraindication; although rare, it carries a mortality rate of 25–30%. 2
Patients who carry the HLA‑B*58:01 allele (particularly individuals of Korean or Han Chinese ancestry) have a markedly increased risk of AHS and should be screened before initiating allopurinol. (moderate‑quality evidence) 1
Do not start allopurinol at high doses (≥ 300 mg/day); high initial doses significantly increase the risk of hypersensitivity reactions and acute gout flares. (moderate‑quality evidence) 1

Do not cap allopurinol at 300 mg/day based solely on renal function; this practice often fails to control hyperuricemia. (moderate‑quality evidence) 1
Do not use probenecid as a first‑line agent; it is less effective than allopurinol and contraindicated in CKD stage ≥ 3. 1
Do not initiate urate‑lowering therapy without concurrent colchicine (or other) prophylaxis, as this markedly raises the risk of acute gout flares. 1

Probenecid is ineffective and contraindicated in patients with an estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m² because uricosuric agents require adequate glomerular filtration to promote uric acid excretion. 3

Febuxostat does not require dose adjustment in patients with mild‑to‑moderate renal impairment. 3