Do NOT use Allopurinol if:

• you are allergic to any ingredient in Allopurinol.

Contact your doctor or health care provider right away if any of these apply to you.

Some medical conditions may interact with Allopurinol. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have kidney or liver disease, heart problems (eg, congestive heart failure), bone marrow problems, high blood pressure, or diabetes.

Some medicines may interact with Allopurinol. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Amoxicillin or ampicillin because the risk of developing a skin rash may be increased
• Chlorpropamide because the risk of low blood sugar may be increased
• Dicumarol or oral anticoagulants (eg, warfarin) because the risk of bleeding may be increased by Allopurinol
• Thiazide diuretics (eg, hydrochlorothiazide) or uricosurics (eg, probenecid) because they may increase the risk of Allopurinol's side effects
• Cyclosporine or thiopurines (eg, azathioprine, mercaptopurine) because the risk of their side effects may be increased by Allopurinol.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Allopurinol may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Important safety information:

• Allopurinol may cause drowsiness. This effect may be worse if you take it with alcohol or certain medicines. Use Allopurinol with caution. Do not drive or perform other possible unsafe tasks until you know how you react to it.
• You may experience an increase in gout attacks for several months after you begin taking Allopurinol. Your doctor may give you another medicine (colchicine) to help decrease these gout attacks. Contact your doctor if you experience frequent or severe gout attacks.
• It may take 2 to 6 weeks to receive the full benefit of Allopurinol.
• Do NOT take more than the recommended dose or use for longer than prescribed without checking with your doctor.
• Allopurinol is not useful for relieving an acute gout attack.
• Follow the diet and exercise program given to you by your health care provider.
• Lab tests, including uric acid levels and kidney and liver function, may be performed while you use Allopurinol. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
• Pregnancy and breast feeding: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Allopurinol while you are pregnant. Allopurinol is found in breast milk. If you are or will be breast-feeding while you use Allopurinol, check with your doctor. Discuss any possible risks to your baby.

All medicines may cause side effects, but many people have no, or minor, side effects.

Check with your doctor if any of these most common side effects persist or become bothersome:

Diarrhea; nausea.

Seek medical attention right away if any of these severe side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blood in urine or painful urination; dark urine; fever, chills, or sore throat; irritation of the eyes; joint pain; loss of appetite; red, swollen, blistered, or peeling skin; stomach pain; unexplained weight loss; unusual bruising or bleeding; unusual muscle pain or weakness; yellowing of the skin or eyes.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.