Indications

Allopurinol is indicated for reducing urate/uric acid formation in conditions where urate/uric acid deposition has already occurred (e.g. gouty arthritis, skin tophi, nephrolithiasis). Allopurinol is indicated for management of 2,8-dihydroxyadenine (2,8-DHA) renal stones related to deficient activity ... Read more Allopurinol is indicated for reducing urate/uric acid formation in conditions where urate/uric acid deposition has already occurred (e.g. gouty arthritis, skin tophi, nephrolithiasis). Allopurinol is indicated for management of 2,8-dihydroxyadenine (2,8-DHA) renal stones related to deficient activity of adenine phospho ribosyltransferase. Allopurinol is indicated for the management of recurrent mixed calcium oxalate renal stones in the presence of hyperuricosuria, when fluid, dietary and similar measures have failed.

Composition

Pharmacology

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. Allopurinol is approximately 90% absorbed from the GI tract. Peak plasma levels generally occur at 1.5 hours to 4.5 hours. It has a plasma half life of about 1 to 2 hours. Approximately 20% of the ingested Allopurinol is excreted in the faeces.

Dosage & Administration

Adults : Allopurinol should be introduced at low dosage e.g. 100 mg/day to reduce the risk of adverse reactions and increased only if the serum urate response is unsatisfactory. Extra caution should be exercised if renal function is poor. The following dosage schedules are suggested: 100 to 200 mg daily in mild conditions, 300 to 600 mg daily in moderately severe conditions, 700 to 900 mg daily in severe conditions. Children : Children under 15 years: 10 to 20 mg/kg body weight/day up to a maximum of 400 mg daily. Use in children is rarely indicated, except in malignant conditions (especially leukaemia) and certain enzyme disorders such as Lesch-Nyhan syndrome. Elderly : In the absence of specific data, the lowest dosage which produces satisfactory urate reduction should be used. Dosage in renal impairment : In severe renal insufficiency, it may be advisable to use less than 100 mg per day or to use single doses of 100mg at longer intervals than one day.

Contraindications

Allopurinol tablet is contra-indicated in patients with known hypersensitive to allopurinol.

Side Effects

Rashes, gastro intestinal disorder’s, rearly malaise, headache, vertigo, drowsiness, visual and test disturbances, hypertension, alopecia, hepatotoxicity, neuropathy, gynaeconastia and blood disorders.

Pregnancy & Lactation

There is inadequate evidence of safety of Allopurinol in human pregnancy. Use in pregnancy only when there is no safer alternative and when the disease itself carries risk for the mother or unborn child. There are no data concerning the effects of allopurinol or its metabolites on the breast-feed baby.

Precautions & Warnings

Allopurinol should be withdrawn immediately when a skin rash or other evidence of sensitivity occurs. Reduced doses should be used in patients with hepatic or renal impairment. Patients under treatment for hypertension or cardiac insufficiency may have some concomitant impairment of renal function and allopurinol should be used with care in this group.

Therapeutic Class

Drugs used in Gout

Storage Conditions

Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.