Active Ingredient

Allopurinol

Allopurinol is a medication used to manage certain medical conditions related to excess uric acid in the body. It is commonly prescribed for individuals who have problems with recurrent gout or certain kinds of kidney stones.

This medication works by reducing the production of uric acid, thereby helping to prevent painful attacks and complications.

Written By Douglas C. Goldberg, MD

Reviewed By Philip Schein, MD

Last Updated 28 Nov 2025

Available Allopurinol Brands

Allopurinol

Strengths 100 mg, 300mg

Zyloprim

Strengths 100mg, 300mg

Allopurinol Uses

Allopurinol is typically used to treat conditions associated with high levels of uric acid.

Prevention of gout attacks
Management of chronic gout
Treatment of kidney stones caused by uric acid
Management of high uric acid levels due to cancer therapy

How Allopurinol Works

Allopurinol works by inhibiting an enzyme called xanthine oxidase. This enzyme is responsible for converting purines into uric acid in the body.

By blocking this enzyme, allopurinol reduces the amount of uric acid produced, helping to prevent the formation of uric acid crystals that can cause pain and inflammation.

Common side effects of Allopurinol

Not everyone experiences side effects from allopurinol, and many are mild and temporary.

Skin rash
Nausea
Diarrhea
Drowsiness
Stomach upset
Headache

If you experience serious or persistent symptoms, contact your doctor for advice.

Frequently Asked Questions

What is the main use of allopurinol?

Allopurinol is primarily used to manage conditions associated with high uric acid levels, such as gout and certain types of kidney stones.

How long does it take for allopurinol to work?

The effects of allopurinol can vary, but it may take a few weeks to see a significant reduction in uric acid levels.

Is it safe to take allopurinol long-term?

Allopurinol is often used for long-term management of uric acid levels, but regular monitoring by a healthcare provider is important.

Can I take allopurinol with other medications?

It’s important to inform your doctor about all medications you are taking, as allopurinol may interact with other drugs.

What should I do if I miss a dose of allopurinol?

If you miss a dose, take it as soon as you remember unless it’s almost time for your next dose. Do not double up on doses.