Allopurinol
Anti-gout Preparations · Xanthine oxidase inhibitor
Indications
For the main clinical manifestations of urate/uric acid deposition. These are gouty arthritis, skin tophi and/or renal involvement through crystal deposition or stone formation. Such clinical manifestations occur in: Idiopathic gout; uric acid lithiasis; acute uric acid nephropathy; neoplastic disease and myelo-proliferative disease after cytotoxic therapy; and certain enzyme disorders which lead to over-production of urate.
Dosage
The dosage should be adjusted by monitoring serum urate concentrations and urinary urate/uric acid levels at appropriate intervals. Dosage frequency: Once a day after a meal or after food. Should the daily dosage exceed 300 mg and gastrointestinal intolerance be manifested, a divided doses regimen may be appropriate. Adults: 2 to 10 mg/kg body wt/day or 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: Prophylaxis of hyperuricaemia associated with cancer chemotherapy, prophylaxis of hyperuricaemic nephropathy, enzyme disorders causing increased serum urate e.g. Lesch-Nyhan Syndrome: 1 mth-15 yr, 10-20 mg/kg daily (max 400 mg daily), preferably after food; 15-18 yr, initially 100 mg daily, increased according to response, max 900 mg daily (doses over 300 mg daily given in divided doses);…
Adverse Effects
Skin reactions; withdraw if occur. Nausea. Acute gout, raised TSH.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Risk cannot be ruled out. Lactation: Caution advised or effect undetermined. Contraindications: Acute gout. Precautions: Elderly. Renal or hepatic dysfunction, hypertension, cardiac insufficiency, thyroid disorders. When initiating therapy give also colchicine or an anti- inflammatory agent for 1 month. Ensure adequate fluid intake.
Interactions
Anticoagulants, chlorpropamide, mercaptopurine or azathioprine, ampicillin, amoxicillin, salicylates, cyclophosphamide, other cytotoxics, theophylline, cyclosporin, phenytoin, didanosine, aluminium hydroxide, diuretics, ACE inhibitors.
Advice to Patient
Take immediately after meals. Contact prescriber if there is unrelieved nausea or vomiting, skin rash/lesions, pain on urination, blood in urine or stool, numbness of extremities, pain or irritation of the eyes, swelling of mouth/lips/tongue, easy bruising or bleeding, unusual fatigue, change in colour of urine or stool, yellowing of skin or eyes. Avoid alcohol during therapy. Take sufficient amount of fluids (2-3 litres per day) to maintain hydration, unless restricted by the prescriber.
Pharmacokinetics
Onset of action: Gout: Decrease in serum and uric acid: 2 to 3 days; Peak effect: 1 week or longer; normal serum urate levels achieved typically within 1 to 3 weeks. Cancer therapy-induced hyperuricemia: Median time to plasma uric acid control: 27 hours. Absorption: Oral: 90% from GI tract. Metabolism: Rapidly oxidized to active metabolites, primarily oxypurinol. Bioavailability: Approx. 49% to 53%. Half-life elimination: Parent drug: Approx. 1 to 2 hours; oxypurinol: Approx. 15 hours. Time to peak, serum: Oral: Allopurinol: 1.5 hours; oxypurinol: 4.5 hours. Excretion: Urine (76% as oxypurinol, 12% as unchanged drug); feces (approx.20%)
Brands with this active ingredient
Compiled by Healify Pharmacy from published drug references. How we compile it →
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