Allopurinol is a xanthine oxidase inhibitor, an enzyme involved in the conversion of hypoxanthine and xanthine into uric acid. Allopurinol is metabolized to oxypurinol, an active metabolite that also inhibits xanthine oxidase. This reduces uric acid production and lowers uric acid concentrations in the blood and urine.
The medicine may be used as part of long-term urate-lowering therapy in patients who require control of elevated uric acid levels, including patients with:
Allopurinol is not intended for self-treatment of asymptomatic hyperuricemia. Treatment should be initiated and monitored by a healthcare professional based on uric acid levels, kidney function, comorbidities, and concomitant medicines.
Research and clinical evidence
Allopurinol is a well-established urate-lowering medicine with decades of clinical use. The American College of Rheumatology guidelines recommend allopurinol as the preferred first-line urate-lowering therapy for gout, including in patients with chronic kidney disease. Current recommendations support starting with a low dose and gradually adjusting treatment according to serum urate levels.
European regulatory guidance for clinical investigation of gout treatments also recognizes serum uric acid as an important efficacy endpoint for urate-lowering therapy and identifies allopurinol as an established active comparator in clinical trials.
Modern gout management emphasizes achieving and maintaining a target serum urate concentration through regular laboratory monitoring and individualized dose adjustment rather than treating symptoms alone.
Allopurinol is used for long-term reduction of uric acid production in conditions associated with excessive uric acid formation or accumulation.
Potential indications include:
Allopurinol inhibits xanthine oxidase, thereby reducing uric acid production. This helps control hyperuricemia and reduces the conditions that promote urate crystal deposition.
The medicine is taken orally after meals with an adequate amount of fluid. The dosage must be individualized by a healthcare professional according to serum uric acid levels, indication, age, and kidney function. Treatment is generally started at a low dose and gradually adjusted based on laboratory monitoring. Dose adjustment is required in patients with impaired kidney function.
Allopurinol is primarily intended for long-term uric acid control and is not a medicine for immediate relief of an acute gout attack. Gout flares may temporarily increase when urate-lowering therapy is initiated, and a healthcare professional may prescribe anti-inflammatory prophylaxis.
Rarely, severe and potentially life-threatening skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and DRESS syndrome, may occur. Treatment should be discontinued and urgent medical attention sought if a skin rash or other signs of hypersensitivity develop.
