Urate-loweringPrescription only
Allopurinol
Tablet
Quick Summary
Allopurinol reduces how much uric acid the body makes.
Gout
High uric acid with kidney stones
Medical Uses
Gout: Preventing attacks.
High uric acid with kidney stones: Some cases.
How it's taken
Take once a day after food. Start low and increase as advised; attacks can briefly increase at first.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Rash
Stop and seek advice.
Stomach upset
Sometimes.
Gout flares
At the start.
Interactions
Azathioprine
Dangerous combination.
Warfarin
Bleeding risk.
Critical Warnings
Severe skin reactions
Black Box Warning: Stop immediately for rash, especially with fever or blisters.
Kidney problems
Dose adjustment.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Allopurinol: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Allopurinol: a medicine to treat gout(opens in a new tab) · NHS