Allopurinol (Zyloprim, Aloprim)

Allopurinol is used for treating gout caused by excessive levels of uric acid in the blood (hyperuricemia). It is a xanthine oxidase inhibitor and is similar to febuxostat (Uloric). Uric acid is a by product from the breakdown of certain proteins (purines) in the body by enzymes called xanthine oxidases. Hyperuricemia occurs when the body produces more uric acid than it can eliminate. The uric acid forms crystals in joints (gouty arthritis) and tissues, causing inflammation and pain. Elevated blood uric acid levels also can cause kidney disease and kidney stones. Allopurinol prevents the production of uric acid by blocking the activity of the enzymes that converts purines to uric acid. Uric acid levels usually begin to fall within 2-3 days of starting treatment and return to their original levels within 7-10 days after allopurinol is stopped. It may take several months of therapy before attacks of gout are controlled. The FDA approved allopurinol in August 1966.

What brand names are available for allopurinol?

Zyloprim, Aloprim

Is allopurinol available as a generic drug?

Yes

Do I need a prescription for allopurinol?

Yes

Allopurinol is used for preventing and/or treating acute attacks of gout, erosive destructive gouty joint disease, uric acid deposits in tissues (tophi), gouty kidney disease, and uric acid stones. Allopurinol also is used to prevent elevation of blood uric acid in patients undergoing chemotherapy for the treatment of certain cancers and in patients with recurrent calcium kidney stones and elevated uric acid levels.

Common side effects include:

• diarrhea,
• nausea,
• rash,
• itching, and
• drowsiness.

The dose of allopurinol for treating gout is 200-600 mg daily depending on severity. The dose for treating high uric acid blood levels due to chemotherapy is 100-800 mg daily starting 1 or 2 days before chemotherapy. It should be taken with food to avoid irritation of the stomach. In order to avoid formation of kidney stones, patients should drink plenty of fluids while taking allopurinol.

: Allopurinol increases blood levels of oral mercaptopurine (Purinethol) and azathioprine (Imuran) by reducing their breakdown in the body. Therefore, the dose of mercaptopurine and azathioprine should be reduced in order to avoid toxicity. There is an increased risk of skin rash in patients taking allopurinol in combination with penicillins. Allopurinol may increase the effect of warfarin by reducing its breakdown.

There are no adequate studies of allopurinol in pregnant women.

Allopurinol is excreted in breast milk. To avoid adverse effects in the infant, nursing mothers taking allopurinol should consider not breastfeeding.

What preparations of allopurinol are available?

Tablets: 100, 300 mg; Powder for injection: 500 mg

How should I keep allopurinol stored?

Tablets should be stored at room temperature between 15 C to 25 C (59 F to 77 F) and in a moisture proof, light- resistant container. Powder should be stored from 20 C to 25 C (68 F to 77 F) and not refrigerated.