ALLOPURINOL allopurinol tablet -ALOPRIM,ZYLOPRIM
Allopurinol is known chemically as 1,5-dihydro-4H -pyrazolo [3,4-d ]pyrimidin-4-one. It is xanthine oxidase inhibitor which is administered orally. Each scored white tablet contains 100 mg allopurinol and the inactive ingredients colloidal silicon dioxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose and sodium starch glycolate. Each scored orange tablet contains 300 mg allopurinol and the inactive ingredients colloidal silicon dioxide, FD&C Yellow No. Lake, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium starch glycolate. Its solubility in water at 37?C is 80 mg/dL and is greater in an alkaline solution.
CLINICAL PHARMACOLOGY
Allopurinol 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 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 of xanthine to uric acid, the end product of purine metabolism in man. Allopurinol is metabolized to the corresponding xanthine analogue, oxipurinol (alloxanthine), which also is an inhibitor of xanthine oxidase.
INDICATIONS AND USAGE
THIS IS NOT AN INNOCUOUS DRUG. IT IS NOT RECOMMENDED FOR THE TREATMENT OF ASYMPTOMATIC HYPERURICEMIA.
Allopurinol 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 pharmacokinetics
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
info. for Patients
Patients should be informed of the following:
They should be cautioned to discontinue allopurinol and to consult their physician immediately at the first sign of skin rash, painful urination, blood in the urine, irritation of the eyes, or swelling of the lips or mouth. They should be reminded to continue drug therapy prescribed for gouty attacks since optimal benefit of allopurinol may be delayed for two to six weeks. They should be encouraged to increase fluid intake during therapy to prevent renal stones. If single dose of allopurinol is occasionally forgotten, there is no need to double the dose at the next scheduled time. There may be certain risks associated with the concomitant use of allopurinol and dicumarol, sulfinpyrazone, mercaptopurine, azathioprine, ampicillin, amoxicillin, and thiazide diuretics, and they should follow the instructions of their physician. Due to the occasional occurrence of drowsiness, patients should take precautions when engaging in activities where alertness is mandatory. Patients may wish to take allopurinol after meals to minimize gastric irritation.
