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.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

This medicine is a hyperuricemic agent used to treat gout and to prevent certain kidney stones from reforming. It may also be used to treat other conditions as determined by your doctor.

Allopurinol is also sometimes used to treat seizures, pain caused by pancreas disease, and certain infections. It is also sometimes used to improve survival after bypass surgery, to reduce ulcer relapses, and to prevent rejection of kidney transplants. Talk to your doctor about the possible risks of using this medication for your condition. This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

Before taking allopurinol,

tell your doctor and pharmacist if you are allergic to allopurinol or any other medications.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention any of the following: amoxicillin (Amoxil, Trimox); ampicillin (Polycillin, Principen); anticoagulants ('blood thinners') such as warfarin (Coumadin); cancer chemotherapy drugs such as cyclophosphamide (Cytoxan) and mercaptopurine (Purinethol); chlorpropamide (Diabinese); diuretics ('water pills'); medications that suppress the immune system such as azathioprine (Imuran) and cyclosporine (Neoral, Sandimmune); other medications for gout such as probenecid (Benemid) and sulfinpyrazone (Anturane); and tolbutamide (Orinase). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have or have ever had kidney or liver disease or heart failure.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking allopurinol, call your doctor.
you should know that allopurinol may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
ask your doctor about the safe use of alcoholic beverages while you are taking allopurinol. Alcohol may decrease the effectiveness of allopurinol.