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What is allopurinol?

Patients with large tumor masses, leukemia, or gout sometimes receive allopurinol (also called Zyloprimâ) which is a medicine used to decrease the level of uric acid in the blood. Allopurinol is available in the following forms:

  • A white 100-mg tablet taken by mouth
  • An orange 300-mg tablet taken by mouth
  • A white 20 mg/mL liquid taken by mouth
  • A clear liquid given by vein (IV)

Possible side effects of allopurinol

  • Feeling drowsy
  • Headache
  • Nausea, vomiting pain in abdomen, or diarrhea

Call the doctor right away if you have any of the following side effects:

  • Chills, fever, muscle aches, or sore throat
  • Joint pain or muscle aches
  • Nausea and vomiting along with a skin rash
  • Sudden decrease in amount of urine, pain while urinating, or blood in urine
  • Skin rash, redness, itching, or hives
  • Trouble breathing
  • Yellow skin or eyes

These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

In case of a severe side effect or reaction, call the doctor, nurse, or pharmacist at 901-595-3300. If you are outside the Memphis area, dial toll-free 1-866-2STJUDE (1-866-278-5833), and press 0 once the call is connected.

Special instructions for allopurinol

  • If you are receiving IV allopurinol and have pain or irritation at the injection site, report it right away to your nurse.
  • You should drink a lot of liquids while you are taking allopurinol. Your doctor or nurse will tell you how much liquid you should drink. You should keep a record of how much you drink and how often you urinate while you are receiving allopurinol.
  • Nausea and vomiting may be decreased if allopurinol is taken with a meal or right after a meal.
  • Store allopurinol tablets at room temperature.
  • Store allopurinol liquid in the refrigerator. Shake liquid well before taking each dose. Do not use after expiration date printed on the label.
  • Antacids may decrease how well allopurinol works. Do not take antacids while you are taking allopurinol.
  • Allopurinol may affect the way other medicines work, including these:
    • mercaptopurine (6-MP)
    • azathioprine
    • ampicillin
    • amoxicillin
    • didanosine
    • cyclosporine
    • warfarin
    • hydrochlorothiazide
    • captopril
    • enalapril

Always give a complete list of medicines you are taking to your doctor or pharmacist. Check with your doctor or pharmacist before taking any new vitamins, herbals, or other medicines.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

ATENCIÓN: si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1-866-278-5833 (TTY: 1-901-595-1040).

تنبيه: إذا كنت تتحدث باللغة العربية فيمكنك الاستعانة بخدمات المساعدة اللغوية المتوفرة لك مجانا. .يرجى الاتصال بالرقم. 5833-278-866-1  (الهاتف النصي: 1040-595-901-1).