Allopurinol is used to treat gout, high levels of uric acid in the body caused by certain cancer medications, and kidney stones. Allopurinol is in a class of medications called xanthine oxidase inhibitors. It works by reducing the production of uric acid in the body. High levels of uric acid may cause gout attacks or kidney stones. Allopurinol is used to prevent gout attacks, not to treat them once they occur.

Allopurinol comes as a tablet to take by mouth. It is usually taken once or twice a day, preferably after a meal. To help you remember to take allopurinol, take it around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take allopurinol exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on a low dose of allopurinol and gradually increase your dose, not more than once a week.

It may take several months or longer before you feel the full benefit of allopurinol. Allopurinol may increase the number of gout attacks during the first few months that you take it, although it will eventually prevent attacks. Your doctor may prescribe another medication such as colchicine to prevent gout attacks for the first few months you take allopurinol. Continue to take allopurinol even if you feel well. Do not stop taking allopurinol without talking to your doctor.

CHECK WITH YOUR DOCTOR AS SOON AS POSSIBLE if you experience a skin rash, skin sores, itching, hives, painful urination, blood in urine, fever, irritation of the eyes, or swelling of lips or mouth. If you notice other effects not listed above, contact your doctor, nurse, or pharmacist.

If overdose is suspected, contact your local poison control center or emergency room immediately.

DO NOT SHARE THIS MEDICINE with others for whom it was not prescribed. DO NOT USE THIS MEDICINE for other health conditions. KEEP THIS MEDICINE out of the reach of children. IF USING THIS MEDICINE FOR AN EXTENDED PERIOD OF TIME, obtain refills before your supply runs out.