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Allopurinol Patient Tips

Medically reviewed by Carmen Pope, BPharm. Last updated on Aug 8, 2025.

1. How it works

2. Upsides

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Allopurinol is used to treat adults with gout or recurrent kidney stones, or to lower uric acid levels in adults and children with leukemia, lymphoma, or solid tumor malignancies who are receiving cancer treatment that increases uric acid levels. If a rash occurs while taking allopurinol, stop taking it immediately and seek urgent medical advice. May also cause diarrhea, nausea, and changes in laboratory tests.

5. Tips

6. Response and effectiveness

7. Interactions

Medicines that interact with allopurinol may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with allopurinol. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with allopurinol include:

The dosage of allopurinol should be reduced by one-third to one-fourth in people also receiving mercaptopurine (Purinethol) or azathioprine (Imuran).

Note that this list is not all-inclusive and includes only common medications that may interact with allopurinol. You should refer to the prescribing information for allopurinol for a complete list of interactions.

Related/similar drugs

References

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.

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