Allopurinol is used to lower uric acid in the blood, to prevent attacks of gout. Allopurinol is not used to treat inflammatory arthritis or osteoarthritis. Allopurinol may cause a rash which, in rare cases, may develop into a serious skin reaction. If you experience a rash while using allopurinol, stop the medication immediately and consult your healthcare provider. A genetic test can help predict ahead of time whether you may be more likely to develop side effects from using allopurinol.
Allopurinol is used to lower uric acid in the blood, to prevent attacks of gout. Allopurinol is not used to treat inflammatory arthritis or osteoarthritis.
Allopurinol is taken orally in pill form.
Allopurinol is available in 100, 200 and 300 mg tablets.
The usual dose is between 100 – 600 mg taken once daily (Maximum dose: 800 mg/day).
If you have poor renal function, you may need a lower daily dose. Please discuss this with your healthcare provider.
In gout, uric acid crystals build up in the joints. Allopurinol works by lowering the amount of uric acid made by body cells.
Be patient, you will not feel the effects of allopurinol right away. It may take a few weeks to feel the effects of allopurinol. The chance of gout attacks may be higher for a few months after you start taking this medication. It is important to keep taking the medication unless told otherwise by a healthcare professional.
To provide symptom relief while you are waiting for allopurinol to work and to protect against gout flares, your prescriber may recommend you take a non-steroidal anti-inflammatory drug (NSAID) or colchicine.
Allopurinol should not be started for the first time during an acute gout attack as it may make the attack worse.
Allopurinol has not been well studied in pregnancy. Human data suggests that risks may be low, and that allopurinol may be safe, but before starting allopurinol tell your healthcare provider if you are pregnant or planning to become pregnant.
Allopurinol does pass into breast milk. Allopurinol is likely safe in breastfeeding/chestfeeding although human data is limited. Allopurinol is considered by the American Academy of Pediatrics to be compatible with breastfeeding/chestfeeding. Breastfed/chestfed infants of lactating parents receiving allopurinol should be monitored for signs of allopurinol side effects, such as rash. Infants whose parent requires treatment with allopurinol may also require periodic blood work.
Allopurinol interacts with a number of other medications. Please speak with your healthcare provider about whether any of the other medications you currently take interact with allopurinol.
Allopurinol may cause a rash which, in rare cases, may develop into a serious skin reaction. If you experience a rash while using allopurinol, stop the medication immediately and consult your healthcare provider.
Anyone who is hypersensitive to allopurinol or has had a previous allergic reaction to allopurinol should avoid the medication.
A common side effect of allopurinol is rash. Sometimes people can develop a more serious type of rash while taking allopurinol. If you develop a rash while taking allopurinol stop the medication and contact your healthcare provider.
Other common side effects include stomach upset and diarrhea.
A rare, but serious side effect of allopurinol is that the medication can cause an allergic reaction. Symptoms include fever, chills, nausea, vomiting, joint pain, and skin rash. If you develop any of these symptoms, stop the medication and contact your healthcare provider. Your risk of this reaction may be increased if you have decreased kidney function or if you take certain medications. Talk to your prescriber about your kidney function and the other medications you take before starting allopurinol.
Take your allopurinol as prescribed and contact your healthcare provider if you have any concerns while taking the medication.
To reduce stomach issues, take allopurinol with food or after a meal.
Poor renal function may limit the use of allopurinol. Its use may also cause severe skin adverse effects in individuals who have a variation in their genetics which predisposes them to these reactions. This genetic variation has been reported more frequently in Asian subpopulations such as Korean, Han-Chinese, or Thai descent.
A genetic test can help predict ahead of time whether you may be more likely to develop side effects from using allopurinol. Speak with your doctor or pharmacist about whether getting a pharmacogenomic test before taking allopurinol is appropriate for you.
Drinking alcohol can contribute to gout flares. It is best to avoid alcohol if you have gout.
Blood tests may be required every 3 – 6 months while you are talking allopurinol. This will help check your complete blood count, liver/kidney function and follow the activity of your gout.
Store this medication at room temperature (20 to 25 degrees Celsius) and keep it out of reach of children.
Contributors
This information was last updated in June 2024 with expert review and advice by:
Alan Low, BSc(Pharm), PharmD, ACPR, FCSHP, CCD, RPh
Clinical Professor, Faculty of Pharmaceutical Sciences, University of British Columbia
Pharmacy Lead and Primary Care Pharmacist, BioPro Biologics Pharmacy
Care Director, MedInfuse Health
Garrett Tang, PharmD, RPh
Pharmacist Services Coordinator, MedInfuse Health
We also thank previous expert contributor:
Jason Kielly, BSc(Pharm), PharmD
Assistant Professor, School of Pharmacy, Memorial University of Newfoundland
Clinical Pharmacist, Rheumatic Health Program, Eastern Health
