Xanthine oxidase inhibitors
Xanthine oxidase inhibitors are prescription medicines that lower the amount of uric acid in the blood. They are used to prevent gout attacks and, in some people, kidney stones. The two common ones are allopurinol and febuxostat. They are taken for the long term and only on a doctor's advice.
Pharmacist review in progress. This page is based on the sources listed below and is being checked by our registered pharmacist.
How do Xanthine oxidase inhibitors work?
These medicines block an enzyme called xanthine oxidase, which the body needs to make uric acid. With less uric acid made, the level in the blood falls and crystals in the joints can slowly dissolve.
Active ingredients of this type
These active ingredients belong to Xanthine oxidase inhibitors. They are listed A to Z.
- Allopurinol: Allopurinol is a prescription medicine that lowers uric acid in the blood.
- Febuxostat: Febuxostat is a prescription medicine for the long-term lowering of uric acid in adults with gout.
Common questions
Do these medicines treat a gout attack?
No. They lower uric acid over the long term to prevent attacks, and attacks can even increase in the first months. Ask your doctor what to take during an attack, and do not stop the medicine on your own.
Why do I need to keep taking it when I have no pain?
The medicine works by keeping uric acid low, and gout can return if it is stopped. Talk to your doctor before making any change.
What are the main safety warnings?
Allopurinol can cause a severe skin rash, so any rash needs urgent advice. Febuxostat carries a boxed warning about a higher risk of death from heart and blood vessel disease in people with existing heart disease. Tell your doctor about your history.
Sources
- Allopurinol: a medicine to prevent gout and kidney stones. NHS (UK)
- Febuxostat tablets: prescribing information (Macleods Pharmaceuticals, label revised 09/2023). DailyMed, US National Library of Medicine
- Adenuric (febuxostat): EPAR medicine overview. European Medicines Agency
- Gout. NHS (UK)
- ATC/DDD Index: M04AA Preparations inhibiting uric acid production. WHO Collaborating Centre for Drug Statistics Methodology
- National Formulary of India. Indian Pharmacopoeia Commission