Allopurinol

Allopurinol is primarily used to prevent gout attacks by lowering uric acid levels in the blood. It is also used to reduce the risk of uric acid kidney stones and to manage raised uric acid levels in people receiving chemotherapy for certain cancers.

Allopurinol begins to lower uric acid levels within a few days of starting treatment. However, it usually takes several months — often three to six months or longer — for uric acid levels to stabilise in the target range and for gout attacks to become less frequent. It is important to keep taking it every day during this time, even if you experience a gout flare in the early weeks.

No. Allopurinol is a preventative medicine and will not relieve an acute gout attack that is already in progress. In fact, starting allopurinol during an acute flare can make the attack worse. Treatment should only be started once an acute attack has fully resolved. If you are experiencing a gout attack, speak to your prescriber about appropriate treatment such as NSAIDs, colchicine, or steroids.

Alcohol — particularly beer, spirits, and other drinks high in purines — can raise uric acid levels and trigger gout attacks. While allopurinol reduces uric acid production, regularly drinking alcohol can counteract its effects. It is advisable to limit alcohol consumption and stay well hydrated. Speak to your prescriber if you are unsure.

For most people with gout, allopurinol is a lifelong treatment. Stopping it allows uric acid levels to rise again, which leads to the return of gout attacks. Do not reduce or stop your treatment without medical advice. Regular blood tests to monitor uric acid levels are recommended during treatment.

Stop taking allopurinol immediately and contact your prescriber or seek medical attention. A skin rash can be a sign of a serious allergic reaction. In rare cases, allopurinol can cause severe skin conditions such as Stevens-Johnson Syndrome (SJS) or Toxic Epidermal Necrolysis (TEN), which require urgent medical treatment. Do not restart allopurinol without explicit medical advice.

Allopurinol can interact with several medicines. It increases the effects of azathioprine and mercaptopurine (used in cancer and autoimmune conditions), which can be dangerous. It can also interact with warfarin, ciclosporin, some diuretics, and ACE inhibitors. Always tell your prescriber and pharmacist about all medicines, supplements, and herbal remedies you are taking before starting allopurinol.

Allopurinol is generally not recommended during pregnancy or breastfeeding. If you are pregnant, planning to become pregnant, or breastfeeding, you must discuss this with your prescriber before starting or continuing treatment. They will weigh the potential risks and benefits and advise you on the safest course of action.