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Drugs reference index «Allopurinol»


Brand names: Zyloprim

Why is Allopurinol prescribed?

Zyloprim is used in the treatment of many symptoms of gout, including tophi (collection of uric acid crystals in the tissues, especially around joints), joint destruction, and uric acid stones. Gout is a form of arthritis characterized by increased blood levels of uric acid. Zyloprim works by reducing uric acid production in the body, thus preventing crystals from forming.

Zyloprim is also used to manage the increased uric acid levels in the blood of people with certain cancers, such as leukemia. It is also prescribed to manage some types of kidney stones.

Most important fact about Allopurinol

Zyloprim will not stop a gout attack that is already underway. However, when taken over a period of several months, Allopurinol will begin to reduce your symptoms. It's important to keep taking it regularly, even if it seems to have no immediate effect.

How should you take Allopurinol?

Take Zyloprim exactly as prescribed. Your doctor will probably start you on a low dosage, increasing it gradually each week until you reach the dosage that is best for you.

A typical starting dose is one 100-milligram tablet per day. You may want to take Zyloprim immediately after a meal to minimize the risk of stomach irritation.

You should avoid taking large doses of vitamin C because of the increased possibility of kidney stone formation.

While taking Zyloprim you should drink plenty of liquids—10 to 12 glasses (8 ounces each) per day—unless otherwise prescribed by your doctor.

To help prevent attacks of gout, you should also avoid beer, wine, and purine-rich foods such as anchovies, sardines, liver, kidneys, lentils, and sweetbreads.

If you have been taking colchicine and/or an anti-inflammatory drug, and others, to relieve your gout, your doctor will probably want you to continue taking Allopurinol while your Zyloprim dosage is being adjusted. Later, when you have had no attacks of gout for several months, you may be able to stop taking these other medications.

If you have been taking a drug that promotes the excretion of uric acid in the urine, such as probenecid or sulfinpyrazone, to try to prevent attacks of gout, your doctor will probably want to reduce or stop your dosage of Allopurinol while increasing your dosage of Zyloprim.

  • If you miss a dose...Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at once.
  • Storage instructions...Store at room temperature in a cool, dry place, away from light.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Zyloprim.

Because a skin reaction, the most common side effect of Zyloprim, may occasionally become severe or even fatal, you should stop taking Zyloprim if you notice even the beginnings of a rash. Such a rash may be itchy or scaly or may make your skin peel off in sheets; it may be accompanied by chills and fever, aching joints, or jaundice.

  • Side effects may include:Acute attack of gout, diarrhea, nausea, rash

Why should Allopurinol not be prescribed?

Do not take Zyloprim if you have ever had a severe reaction to it in the past.

Special warnings about Allopurinol

If you notice a rash or other signs of an allergic reaction, stop taking Zyloprim immediately and consult your doctor. In some people, a Zyloprim-induced rash may lead to a serious skin disease, generalized inflammation of a blood or lymph vessel, irreversible liver damage, or even death.

You may experience acute attacks of gout more often in the early stages of Zyloprim therapy, even when normal uric acid levels have been attained. These attacks will become shorter and less severe after several months of therapy.

A kidney problem may turn a normal dose of Zyloprim into an overdose. If you have a kidney disease, or a condition such as diabetes or high blood pressure that may affect your kidneys, your doctor should prescribe Zyloprim cautiously and order periodic blood and urine tests to assess your kidney function.

Because Zyloprim may make you drowsy, do not drive or perform hazardous tasks until you know how the medication affects you.

It may be 2 to 6 weeks before you see any results from Allopurinol.

Possible food and drug interactions when taking Allopurinol

If Zyloprim is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Zyloprim with the following:

AmoxicillinAmpicillinAzathioprineBlood thinnersCyclosporineDrugs for diabetesMercaptopurineProbenecidSulfinpyrazoneTheophyllineThiazide diureticsVitamin C

Special information if you are pregnant or breastfeeding

The effects of Zyloprim during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, notify your doctor immediately. Zyloprim should be taken during pregnancy only if it is clearly needed.

Zyloprim appears in breast milk; what effect it may have on a nursing baby is unknown. Caution is advised when Zyloprim is taken during breastfeeding.

Recommended dosage for Allopurinol


Your doctor will tailor the dosage of Zyloprim individually to control the severity of symptoms and to bring the uric acid levels to normal or near normal.


The usual starting dose is 100 milligrams once daily. Your doctor may increase your dose by 100 milligrams per day at 1-week intervals until desired results are attained. The average dose is 200 to 300 milligrams per day for mild gout and 400 to 600 milligrams daily for moderate to severe gout. The most you should take in a day is 800 milligrams.

Recurrent Kidney Stones

The usual dose is 200 to 300 milligrams daily, divided into smaller doses or taken as one dose.

Management of Uric Acid Levels in Certain Cancers

The usual dose is 600 to 800 milligrams daily for 2 to 3 days, together with a high fluid intake.


The usual recommended dose for children 6 to 10 years of age is 300 milligrams daily for the management of uric acid levels in certain types of cancer. Children under 6 years of age are generally given 150 milligrams daily.


Although no specific information is available regarding Zyloprim overdosage, any medication taken in excess can have serious consequences. If you suspect an overdose of Zyloprim, seek medical attention immediately.

  • Allopurinol Prescribing Information (FDA)
  • Allopurinol MedFacts Consumer Leaflet (Wolters Kluwer)
  • Allopurinol Professional Patient Advice (Wolters Kluwer)
  • allopurinol Concise Consumer Information (Cerner Multum)
  • allopurinol Intravenous Advanced Consumer (Micromedex) - Includes Dosage Information
  • Aloprim Prescribing Information (FDA)
  • Zyloprim Prescribing Information (FDA)

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