Preventing Gout With Zyloprim (Allopurinol)

This treatment works by preventing buildup of uric acid

A woman taking a pill with a glass of water.
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Zyloprim (allopurinol) is a prescription drug used to prevent chronic gout. It is marketed under a number of different brand names include Lopurin and Alloprim.

Zyloprim works by blocking the production of a waste byproduct known as uric acid. Uric acid is produced when purines in certain foods (particularly meats and internal organs like liver or kidneys) are metabolized. Excessive concentrations of uric acid can cause crystals to form in the joints, causing the arthritis symptoms we associate with gout.

Zyloprim is used to control high uric acid levels caused by cancer chemotherapy and to prevent the development of kidney stones.


Zyloprim is available as a 100 milligram (mg) tablet. It is taken either once or twice daily depending on the dosage. It is best taken after a meal with lots of water to reduce the risk of stomach upset.

The ideal dosage is determined by how effectively it reduces the uric acid levels in the blood. The dose may be gradually increased in increments of 100 mg until the optimal uric acid level is achieved. Doctors can monitor these levels with routine blood tests.

The typical dosage of Zyloprim is between 200 to 300 milligrams per day. In some cases, 400 to 600 milligrams may be prescribed to treat moderate to severe tophaceous gout. The maximum daily dose is 800 milligrams per day.

What to Expect

You will need to take Zyloprim as prescribed to ensure that therapeutic drug levels are maintained in the blood.

Inconsistent or inadequate dosing can undermine the benefits of treatment.

It may take several months before you achieve full relief of symptoms. In some cases, there may even be an increase in the number of gout attacks as your body tries to counteract the effects of the drug. But, In time and with persistent, your body will gradually adapt.

During the initial phase of treatment, the drug Colcrys (colchicine) may be prescribed to help reduce the risk of gout attacks.

Drug Interactions

People who take any of following drugs should tell their doctor as they may interfere with the effectiveness of Zyloprim:

In most cases, dose adjustment can correct any adverse interactions.

Side Effects

Zyloprim may sometimes cause side effects which are typically mild and resolve on their own. The most common include:

  • Upset stomach
  • Diarrhea
  • Drowsiness
  • Rash

Zyloprim can sometimes cause liver toxicity, resulting in tiredness, weight loss, loss of appetite, jaundice (yellowing of the eyes and skin), and pain in the upper right abdominal area. Regular liver enzyme testing can help avoid this.

While less common, Zyloprim has been known to cause hypersensitivity reactions in some, particularly Asians with advanced or chronic kidney disease. Genetic testing can be performed to assess if a person has the HLA-B*5801 mutation consistent with the risk of hypersensitivity.


Alcohol can undermine the benefits of treatment by increasing the uric acid salts associated with gout. As such, efforts should be made to reduce alcohol consumption.

Similarly, overuse of vitamin C can cause excessive urine acidity. Vitamin C supplementation should be limited to no more than 500 milligrams per day.

While there are no contraindications to using Zyloprim during pregnancy or breastfeeding, the data remains limited. Speak with your doctor if you are of child-bearing age to better understand the benefits and possible consequences of Zyloprim use.


U.S. National Library of Medicine. "Allopurinol." Medline Plus. Bethesda, Maryland; updated August 15, 2017.