PURINOL

ALLOPURINOL

Aallopurinol reduces serum and urinary uric acid concentrations. Its use should be individualized for each patient and requires an understanding of its mode of action and pharma-cokinetics. Allopurinol is indicated in: The management of patients with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy). The management of patients with leukemia, lymphoma and malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels. Treatment with Allopurinol should be discontinued when the potential for overproduction of uric acid is no longer present. The management of patients with recurrent calcium oxalate calculi whose daily uric acid excretion exceeds 800 mg/day in male patients and 750 mg/day in female patients. Therapy in such patients should be carefully assessed initially and reassessed periodically to determine in each case that treatment is beneficial and that the benefits outweigh the risks.

Drugs used in Gout

Allopurinol is a xanthine oxidase inhibitor which is administered orally. It acts on purine catabolism without disrupting the biosynthesis of purines. It reduces the production of uric acid by inhibiting the biochemical reactions immediately preceding its formation. Allopurinol is a structural analogue of the natural purine base, hypoxanthine. It is an inhibitor of xanthine oxidase, the enzyme responsible for the conversion of hypoxanthine to xanthine and xanthine to uric acid, the end product of purine metabolism.

Adults: Mild gout: 200 to 300 mg/day. Moderately severe tophaceous gout: 400 to 600 mg/day. The minimal effective dosage is 100 to 200 mg daily and the maximal recommended dosage is 800 mg daily. To reduce the possibility of flare-up of acute gouty attacks, it is recommended that the patient start with a low dose of Allopurinol (100 mg daily) and increase at weekly intervals by 100 mg until a serum uric acid level of 6 mg/day or less is attained but without exceeding the maximal recommended dosage. Recurrent calcium oxalate stones: 200 to 300 mg/day. Children: Age 6-10 years: In secondary hyperuricemia associated with malignancies may be given 300 mg Allopurinol daily. Age under 6 years: generally given 150 mg daily.

Anticoagulant: Allopurinol prolongs the half life of the anticoagulant, dicumarol. Diuretic: Concomitant use of Allopurinol and thiazide diuretics may contribute to the enhancement of Allopurinol toxicity. Cytotoxic agent: Enhanced bone marrow suppression by cyclophosphamide and other cytotoxic agent has been reported among patients with neoplastic disease.

Patients who have developed a severe reaction to allopurinol should not be restarted the drug. Allopurinol should be withdrawn immediately when a skin rash or other evidence or sensitivity occurs. Dosage reduction should be considered in the presence of severe hepatic or renal disorder.

The most frequent adverse reaction to allopurinol is skin rash such as, pruritic maculopapular skin eruptions, sometimes scaly or exfoliative. Some patients with the most severe reaction, also had fever, chill, arthralgias, cholestatic jaundice, eosinophilia and mild leukocytosis or leukopenia.

No adequate data had found in pregnant women. This drug should be used during pregnancy only if clearly indicated. Allopurinol has been found in breast milk, caution should be exercised when Allopurinol is administered to a lactating mother.

Store in a place which protects from heat & light.