• Basic Info
• Top Questions
• Clinical Info
• Interactions

Before taking allopurinol, tell your doctor if you are using any of the following drugs:

• azathioprine (Imuran);

• chlorpropamide (Diabinese);

• cyclosporine (Gengraf, Sandimmune, Neoral);

• mercaptopurine (Purinethol);

• an antibiotic such as ampicillin (Principen, Omnipen, others) or amoxicillin (Amoxil, Augmentin, Trimox, Wymox);

• a blood thinner such as dicoumarol or warfarin (Coumadin); or

• a diuretic (water pill).

This list is not complete and there may be other drugs that can interact with allopurinol. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using allopurinol and call your doctor at once if you have any of these serious side effects:

• the first sign of any skin rash, no matter how mild;

• pain or bleeding when you urinate;

• urinating less than usual or not at all;

• fever, sore throat, and headache with a severe blistering, peeling, and red skin rash;

• bruising, severe tingling, numbness, pain, muscle weakness;

• easy bruising or bleeding, unusual weakness;

• fever, chills, body aches, flu symptoms;

• jaundice (yellowing of the skin or eyes); or

• seizure (convulsions).

Less serious side effects may include:

• nausea, vomiting, diarrhea;

• dizziness or drowsiness;

• increased sweating; or

• joint pain.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.