Archive for Agents for Gout

Allopurinol Drug – How does Allopurinol Works?

Allopurinol – Type of Drug – Some Interactions occurring with Allopurinol

Type of Drug:

Agent for gout; xanthine oxidase inhibitor.

How the Allopurinol Product Works:

Gout is a hereditary form of arthritis caused by increased uric acid levels in the blood. Allopurinol prevents the formation of uric acid in the body by inhibiting an enzyme (xanthine oxidase) involved in the production of uric acid.

Uses of The Allopurinol:

To prevent the signs and symptoms of primary or secondary gout (eg, acute attacks, tophi, joint destruction, uric acid kidney stones, kidney damage).

To manage uric acid elevations in serum (hyperuricemia) and urine (uricosuria) in patients treated for leukemia, lymphoma, and other malignancies.


Do not use in the following situations: Allergy or severe reaction to allopurinol.

Use with caution in the following situations:

Acute attacks of gout may increase during the early stages of allopurinol use. The attacks usually become shorter and less severe after several months of therapy. Even with adequate therapy, it may require several months to deplete the uric acid pool sufficiently to control acute episodes.

Fluid intake: Drink a sufficient amount of fluid to yield a urinary output of at least 2 quarts a day and to maintain a neutral or slightly alkaline urine. This will help prevent the formation of kidney stones while taking allopurinol.

Allergy: Discontinue at the first appearance of rash or other signs of an allergic reaction. In some instances, rash may be followed by more severe reactions such as itching; hives; red lesions; and loss of hair, skin, or fingernails.

Pregnancy: These are no adequate and well-controlled studies in pregnant woman. Use only if clearly needed and potential benefits to the mother outweigh the possible hazard to the fetus.

Breastfeeding: Allopurinol appears in breast milk. Consult your doctor before you begin breastfeeding.

Children: Allopurinol is rarely used in children with the exception of those with hyperuricemia secondary to malignancy or to certain rare inborn errors of purine metabolism.

Lab Tests: Lab tests will be required during treatment with allopurinol. Tests may include uric acid level, blood counts, and kidney and liver function tests.

Drug Interactions:

Tell your doctor or pharmacist if you are taking or if you are planning to take any over-the-counter or prescription medications or dietary supplements with allopurinol. Doses of one or both drugs may need to be modified or a different drug may need to be prescribed. The following drugs and drug classes interact with allopurinol.

  • Aamoxicillin (eg, Amoxil)
  • Ampicillin (eg, Principen)
  • Anticoagulants (eg, dicumarol)
  • Azathioprine (eg, Imuran)
  • Chlorpropamide (eg, oiabinese)

Side Effects:

Every drug is capable of producing side effects. Many allopurinol users experience no, or minor, side effects. The frequency and severity of side effects depend on many factors including dose, duration of therapy, and individual susceptibility. Possible side effects include:

Digestive Tract: Stomach upset; diarrhea; nausea.

Skin: Chills; rash; scaling or sloughing of skin.

Other: Acute gout attacks; joint pain; drowsiness.

Guidelines for Use:

  • Gout and secondary hyperuricemia (maintenance) – The average dose of allopurinol is 200 to 300 mg/day for patients with mild gout and 400 to 600 mg/day for those with moderate-to-severe gout. The dose may be administered in divided doses or as a single equivalent dose with the 300 mg tablet. Daily doses more than 300 mg should be administered in divided doses. The minimum effective dose is 100 to 200 mg/day, and the maximum recommended dose is 800 mg/day. It is recommended that the patient be started with a low dose (100 mg) and increased at weekly intervals by 100 mg until a serum uric acid level of 6 mg/dL or less is attained, not exceeding the maximum recommended dose.
  • Prevention of uric acid kidney disease during the vigorous chemotherapy of tumors – 600 to 800 mg/day for 2 or 3 days along with a high fluid intake.
  • Recurrent kidney stones in patients with high levels of uric acid in the urine – 200 to 300 mg/day in single or divided doses.
  • Secondary hyperuricemia in children – Children 6 to 10 years of age with secondary hyperuricemia (increased uric acid in the blood) associated with severe diseases may be given 300 mg/day, while those less than 6 years of age are generally given 150 mg/day.
  • To minimize stomach upset, take after meals.
  • If a dose is missed, simply take your next dose at the regularly scheduled time. Do not attempt to make up for the missed dose.
  • May take 2 to 6 weeks to become effective. Do not skip doses or stop taking this drug prematurely.
  • Drink plenty of fluids while taking allopurinol, at least 10 to 12 full (8 oz) glasses a day, to prevent kidney stones.
  • May cause drowsiness. Use caution while driving or performing other tasks requiring alertness, coordination, or physical dexterity.
  • Discontinue allopurinol and notify your doctor immediately at the first sign of appetite loss, weight loss, rash, painful urination, blood in the urine, irritation of the eyes, or swelling of the lips or mouth.
  • Avoid large doses of vitamin C as this may increase the possibility of kidney stone formation.
  • Allopurinol does not treat acute gout attacks. Other medications (eg, colchicine, indomethacin) are used to treat the acute attack.
  • Lab tests will be required to monitor therapy. Be sure to keep appointments.
  • Store at 59° to 77° F in a dry place. Protect from light.

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