Allopurinol

From PharmDatabase.org

Generic name: Allopurinol
Brand names: Aloprim, Purinol, Zyloprim
Related Medical Conditions: Gout, Gouty Arthritis, Kidney Stones
Related Groups: Antigout Agent, Antihyperuricemic, Xanthine Oxidase Inhibitor

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Allopurinol Articles

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Contents 1 What is Allopurinol? 2 Allopurinol Usage and Dosage 3 Allopurinol Side Effects 4 Other Drugs Interaction 5 Allopurinol Storage 6 Articles

What is Allopurinol?

Allopurinol is used to treat gout, chronic gout (gouty arthritis), high levels of uric acid in the body caused by certain cancer medications, and kidney stones. This condition is caused by too much uric acid in the blood. Allopurinol is in a class of medications called xanthine oxidase inhibitors. It works by reducing the production of uric acid in the body. High levels of uric acid may cause gout attacks or kidney stones. Allopurinol is used to prevent gout attacks, not to treat them once they occur.

Allopurinol will not relieve a gout attack that has already started. Also, it does not cure gout, but it will help prevent gout attacks. However, it works only after you have been taking it regularly for a few months. Allopurinol will help prevent gout attacks only as long as you continue to take it.

Allopurinol is available only with your doctor's prescription in the following dosage form:

Oral

• Tablets (U.S. and Canada)

Parenteral

• Injection (U.S.)

Allopurinol Usage and Dosage

If this medicine upsets your stomach, it may be taken after meals. If stomach upset (indigestion, nausea, vomiting, diarrhea, or stomach pain) continues, check with your doctor.

In order for this medicine to help you, it must be taken regularly as ordered by your doctor.

To help prevent kidney stones while taking allopurinol, adults should drink at least 10 to 12 full glasses (8 ounces each) of fluids each day unless otherwise directed by their doctor. Check with the doctor about the amount of fluids that children should drink each day while receiving this medicine. Also, your doctor may want you to take another medicine to make your urine less acidic. It is important that you follow your doctor's instructions very carefully.

For patients taking allopurinol for chronic gout:

• After you begin to take allopurinol, gout attacks may continue to occur for a while. However, if you take this medicine regularly as directed by your doctor, the attacks will gradually become less frequent and less painful. After you have been taking allopurinol regularly for several months, the attacks may stop completely.
• Allopurinol is used to help prevent gout attacks. It will not relieve an attack that has already started. Even if you take another medicine for gout attacks, continue to take this medicine also.

The dose of allopurinol will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of allopurinol. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take each day and the number of times that you take the medicine every day depend on the strength of the medicine, on the dose that you need, and on the reason you are taking allopurinol. Up to 300 milligrams (mg) of allopurinol can be taken at one time. Doses larger than 300 mg a day should be divided into smaller amounts that are taken two, three, or even four times a day.

For the oral dosage form (tablets):

• For gout:
  • Adults—At first, most people will take 100 mg a day. After about a week, your doctor will probably increase the dose gradually until the amount of uric acid in your blood has been lowered to normal levels. The total amount of allopurinol is usually not more than 800 mg a day. After the uric acid has remained at normal levels for a while, your doctor may lower your dose gradually until you are taking the smallest amount of medicine that will keep the uric acid from increasing again.
  • Children and teenagers—Use and dose must be determined by the doctor.
• For kidney stones:
  • Adults—100 to 800 mg a day, depending on the kind of kidney stones.
  • Children and teenagers—Use and dose must be determined by the doctor.
• For preventing or treating medical problems that may occur if certain treatments increase the amount of uric acid in the blood:
  • Adults—600 to 800 mg a day, starting one to three days before the treatment.
  • Children—The dose depends on the child's age
  • Children up to 6 years of age: 50 mg (one-half of a 100-mg tablet) three times a day.
  • Children 6 to 10 years of age: One 100-mg tablet three times a day or one 300-mg tablet a day.
  • Children 11 years of age and older: The dose may be the same as for adults.

For the parenteral dosage form (injection):

• For preventing or treating medical problems that may occur if certain treatments increase the amount of uric acid in the blood:
  • Adults—200 to 400 mg per square meter of body surface area (mg/m2) a day, injected into a vein. Starting one to two days before treatment, this dose may be given as a single dose or divided into smaller doses as determined by your doctor. Your doctor will check your uric acid level and may change your dose based on the level. However, the dose is usually not more than 600 mg per day.
  • Children—At first, 200 mg per square meter of body surface area (mg/m2) per day, injected into a vein. Starting one to two days before treatment, this dose may be given as a single dose or divided into smaller doses as determined by your doctor . Your doctor will check your uric acid level and may change your dose based on the level.

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Allopurinol Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Stop taking this medicine and check with your doctor immediately if any of the following side effects occur:

More common

• Skin rash or sores, hives, or itching

Rare

• Black, tarry stools; bleeding sores on lips; blood in urine or stools; chills, fever, muscle aches or pains, nausea, or vomiting—especially if occurring with or shortly after a skin rash; difficult or painful urination; pinpoint red spots on skin; redness, tenderness, burning, or peeling of skin; red and/or irritated eyes; red, thickened, or scaly skin; shortness of breath, troubled breathing, tightness in chest, or wheezing; sores, ulcers, or white spots in mouth or on lips; sore throat and fever; sudden decrease in amount of urine; swelling in upper abdominal (stomach) area; swelling of face, fingers, feet, or lower legs ; swollen and/or painful glands; unusual bleeding or bruising; unusual tiredness or weakness; weight gain (rapid); yellow eyes or skin

Also, check with your doctor as soon as possible if any of the following side effects occur:

Rare

• Loosening of fingernails; numbness, tingling, pain, or weakness in hands or feet; pain in lower back or side; unexplained nosebleeds

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

Less common or rare

• Diarrhea; drowsiness; headache; indigestion; nausea or vomiting occurring without a skin rash or other side effects; stomach pain occurring without other side effects; unusual hair loss

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Other Drugs Interaction

Taking ampicillin (Principen, Omnipen, others) or amoxicillin (Amoxil, Augmentin, Trimox, Wymox, others) may increase the risk that a rash will develop during allopurinol therapy. Tell your doctor that you are taking allopurinol if you need to take ampicillin or amoxicillin.

Thiazide diuretics (water pills) may increase the amount of allopurinol in your blood. Tell your doctor if you are taking a diuretic such as

• hydrochlorothiazide (Hydrodiuril, Hygroton, HCTZ, others),
• chlorothiazide (Diuril, others),
• chlorthalidone (Thalitone, others), or
• indapamide (Lozol).

Allopurinol may also increase the effects of the certain other drugs. Before taking allopurinol, tell your doctor if you are taking any of the following medicines:

• azathioprine (Imuran),
• mercaptopurine (Purinethol),
• drugs used to treat cancer,
• cyclosporine (Sandimmune, Neoral),
• chlorpropamide (Diabinese),
• warfarin (Coumadin), or

theophylline (Theochron, Theolair, Theo-Dur, others).

You may require a dosage adjustment or special monitoring if you are taking any of the drugs listed above.

Drugs other than those listed here may also interact with allopurinol. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.

Allopurinol Storage

To store this medicine: Keep out of the reach of children. Store away from heat and direct light. Do not store this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down. Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

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