Allopurinol: the most-used uric acid drug — how long, what dose, is it hard on the liver and kidneys?

Allopurinol blocks xanthine oxidase so the body makes less uric acid. It is the first-line gout drug worldwide and costs pennies.

Dosing

• Start 100 mg/day (50 mg with kidney disease).
• Increase 100 mg every 2–4 weeks until uric acid <360 µmol/L.
• Typical maintenance 200–400 mg; 100 mg is rarely enough.

How long?

Years, often lifelong. Stopping lets uric acid rebound within weeks.

Liver and kidneys

At the right dose it protects the kidneys. The rare danger is severe skin allergy (SJS) in the first 2 months, more common with gene HLA-B*5801 in Asians — screening is available.

Tips

1. Take after food with water.
2. Expect possible flares in month one; low-dose colchicine helps.
3. Rash, itching, fever → stop and see a doctor.
4. Retest every 2–4 weeks until on target.