Allopurinol: Uses, Side Effects

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:

  • kidney disease;
  • liver disease;
  • diabetes;
  • congestive heart failure;
  • high blood pressure; or
  • if you are receiving chemotherapy.

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.


Side effects

Get emergency medical help if you have signs of an allergic reaction to allopurinol (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

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:

  • drowsiness;
  • rash;
  • abnormal liver function tests;
  • nausea, vomiting, diarrhea;
  • headache; or
  • changes in your sense of taste.

What other drugs will affect allopurinol?

Tell your doctor about all your other medicines, especially:

  • azathioprine or mercaptopurine;
  • chlorpropamide;
  • cyclosporine;
  • an antibiotic such as ampicillin or amoxicillin;
  • a blood thinner such as warfarin, Coumadin, Jantoven; or
  • a diuretic or “water pill”.

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.


Keyword: allopurinol.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.