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Generic Name: allopurinol (AL oh PURE i nol)
Brand Names: Zyloprim, Lopurin, Aloprim

Medically reviewed on Oct 14, 2018

What is allopurinol?

Allopurinol reduces the production of uric acid in your body. Uric acid buildup can lead to gout or kidney stones.

Allopurinol is used to treat gout or kidney stones, and to decrease levels of uric acid in people who are receiving cancer treatment.

Allopurinol may also be used for purposes not listed in this medication guide.

Important Information

You should not use allopurinol if you have ever had a serious allergic reaction to it. Stop taking the medicine and call your doctor at once if you have any signs of skin rash, no matter how mild.

Allopurinol can lower blood cells that help your body fight infections. This can make it easier for you to bleed from an injury or get sick from being around others who are ill. Your blood may need to be tested often. Visit your doctor regularly.

Avoid drinking alcohol. It can make your condition worse. Allopurinol may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Before taking this medicine

You should not take allopurinol if you are allergic to it.

To make sure allopurinol is safe for you, tell your doctor if you have ever had:

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.

How should I take allopurinol?

Take allopurinol exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Take each dose with a full glass of water. To reduce your risk of kidney stones forming, drink 8 to 10 full glasses of fluid every day, unless your doctor tells you otherwise.

Take with food if allopurinol upsets your stomach.

You may have gout attacks more often when you first start taking allopurinol. Your doctor may recommend other gout medication to take at this time. Keep using your medication as directed and tell your doctor if your symptoms do not improve after 6 weeks of treatment.

You may need to follow a special diet while using allopurinol. Follow all instructions of your doctor or dietitian. Learn about the foods to eat or avoid to help control your condition.

Store at room temperature away from moisture and heat.

Allopurinol dosing information

Usual Allopurinol Adult Dose for Gout:

Initial: 100 mg orally once a day.
Maintenance: 200 to 300 mg (mild gout) orally once a day or 400 to 600 mg/day (moderately severe tophaceous gout) in divided doses.

Usual Adult Dose for Hyperuricemia Secondary to Chemotherapy:

Parenteral: 200 to 400 mg/m2/day to a maximum of 600 mg/day
Oral: 600 to 800 mg/day for 1 to 3 days with consumption of at least 2 L of fluid/day.

200 to 300 mg/day orally until patient no longer at high risk for developing hyperuricemia.

Usual Adult Dose for Calcium Oxalate Calculi with Hyperuricosuria:

Initial: 200 to 300 mg orally once a day.
Maintenance: 300 mg/day or less.

Usual Adult Dose for Congestive Heart Failure:

Study (n=11) to prevent the formation of superoxide free radicals and improve endothelial function (in NYHA class II to III chronic heart failure): 300 mg orally daily for 1 month

Usual Adult Dose for Cardiothoracic Surgery:

Studies: Coronary Artery Bypass Graft Surgery
600 mg orally one day prior to surgery and another 600 mg orally the day of surgery.

Usual Adult Dose for Leishmaniasis:

Study (n=31 - Cutaneous leishmaniasis: 20 mg/kg/day plus low-dose meglumine antimoniate (30 mg/kg/day) for 20 days.

Case Reports - Visceral leishmaniasis, post renal transplant: 300 mg daily plus meglumine antimoniate (50 mg/kg/day)

Usual Adult Dose for Mania:

Case Reports -- Mania (bipolar I) associated with hyperuricemia: 300 mg orally daily.

Usual Adult Dose for High Risk Percutaneous Transluminal Angioplasty:

Study (n=38) - Primary Percutaneous Transluminal Coronary Angioplasty (PTCA):
400 mg orally administered immediately after admission to the emergency department (approximately 60 minutes before reperfusion) and after primary PTCA was completed.

Usual Adult Dose for Reactive Perforating Collangenosis:

Case Report: 100 mg orally daily.

Usual Pediatric Dose for Hyperuricemia Secondary to Chemotherapy:

Parenteral :
Less than or equal to 10 years: 200 mg/m2/day in 1 to 3 equally divided doses not to exceed 600 mg/24 hours. All doses greater than 300 mg should be given in equally divided doses.
Greater than 10 years: 200 to 400 mg/m2/day administered in 1 to 3 equally divided doses, not to exceed 600 mg/24 hours.

Less than 6 years: 150 mg/day orally in 3 divided doses.
6 to 10 years: 300 mg/day orally in 2 to 3 divided doses.
Greater than 10 years: 600 to 800 mg/day in 2 to 3 equally divided doses

Usual Pediatric Dose for Leishmaniasis:

Greater than 5 years old
Study (n=31) - Cutaneous leishmaniasis: 20 mg/kg/day plus low-dose meglumine antimoniate (30 mg/kg/day) for 20 days.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking allopurinol?

Avoid driving or hazardous activity until you know how allopurinol will affect you. Your reactions could be impaired.

Avoid drinking alcohol. It may worsen your condition.

Allopurinol side effects

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

Stop using this medicine and call your doctor at once if you have:

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

  • flu symptoms, joint pain, easy bruising, unusual bleeding;

  • painful urination, blood in the urine;

  • little or no urination;

  • numbness, tingling, burning pain;

  • worsening gout symptoms; or

  • liver problems - loss of appetite, weight loss, stomach pain (upper right side), itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common allopurinol side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect allopurinol?

Tell your doctor about all your other medicines, especially:

This list is not complete. Other drugs may interact with allopurinol, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use allopurinol only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.