What is Allopurinol?
Allopurinol is a medication used to lower uric acid levels in the blood. It is the most commonly prescribed long-term treatment for gout. High levels of uric acid cause the formation of crystals in the joints, which leads to painful gout attacks. By reducing uric acid production, allopurinol helps prevent these attacks and, over time, dissolves existing crystals.
Who is it For?
Allopurinol is recommended for people who:
- Have frequent gout attacks (two or more per year)
- Have tophaceous gout (visible uric acid crystal deposits)
- Have gout-related kidney problems
- Have kidney stones caused by uric acid
How to Take it
Allopurinol is taken as a daily tablet, usually starting at 100mg and gradually increasing. It must be taken long-term — it is not a cure and should not be stopped without medical advice. Importantly, allopurinol should not be started during an acute gout attack, as it can initially worsen symptoms. It should be started once the attack has fully resolved.
Side Effects
- Rash — if you develop a rash, stop taking it and see your doctor immediately, as a rare but serious allergic reaction (Stevens-Johnson syndrome) is possible
- Nausea and stomach upset
- Increased frequency of gout attacks when first starting (this should settle)
- Drowsiness
Monitoring
Regular blood tests are needed to check uric acid levels and kidney function. The target uric acid level is usually below 300–360 micromol/L. Drinking plenty of water (at least 2 litres a day) is recommended to help flush uric acid from the body.