APO-ALLOPURINOL

What it is

APO-ALLOPURINOL contains allopurinol and is available in 100 mg and 300 mg tablet strengths.

Approved indications

— Gouty arthritis, skin tophi and renal involvement through crystal deposition or stone formation. — Idiopathic gout. — Uric acid lithiasis. — Acute uric acid nephropathy. — Neoplastic disease and myeloproliferative disease with high cell turnover rates where high urate levels occur either spontaneously or after cytotoxic therapy. — Certain enzyme disorders which lead to overproduction of urate including hypoxanthine guanine phosphoribosyltransferase (including Lesch-Nyhan syndrome), glucose-6-phosphatase (including glycogen storage disease), phosphoribosylpyrophosphate synthetase and phosphoribosylpyrophosphate amidotransferase. — Management of 2,8-dihydroxyadenine (2,8-DHA) renal stones related to deficient activity of adenine phosphoribosyl transferase. — Management of recurrent mixed calcium oxalate renal stones in the presence of hyperuricosuria, when fluid, dietary and similar measures have failed.

Dosing overview

APO-ALLOPURINOL may be taken orally once a day after a meal. If the daily dosage exceeds 300 mg and gastrointestinal intolerance occurs, a divided dose regimen may be appropriate. In elderly patients, the lowest dosage which produces satisfactory urate reduction should be used, with particular attention to dosage advice in renal disorders. In patients with impaired renal function, treatment should be initiated with a maximum dose of 100 mg/day and increased only if the serum and/or urinary urate response is unsatisfactory.

Key safety warnings

APO-ALLOPURINOL should be withdrawn immediately when a skin rash or other evidence of sensitivity occurs. Allopurinol should be discontinued at the first appearance of skin rash or signs indicating an allergic reaction. A skin rash may be followed by more severe hypersensitivity reactions including exfoliative, urticarial and purpuric lesions, Stevens-Johnson syndrome, drug rash with eosinophilia and systemic symptoms (DRESS), toxic epidermal necrolysis, generalised vasculitis, irreversible hepatotoxicity and rarely death. APO-ALLOPURINOL treatment should not be started until an acute attack of gout has completely subsided, as further attacks may be precipitated. In the early stages of treatment, acute gouty arthritis may be precipitated. Prophylaxis with a suitable anti-inflammatory agent or colchicine (0.5 mg three times a day) for at least one month is advisable. The HLA-B*5801 allele is associated with the risk of developing allopurinol-related hypersensitivity syndrome and Stevens-Johnson syndrome/toxic epidermal necrolysis. The frequency varies by ethnic population: up to 20% in Han Chinese, 8–15% in Thai, about 12% in Korean, and 1–2% in Japanese or European populations. Screening for HLA-B*5801 should be considered before starting treatment in patient subgroups where prevalence is high. The occurrence of hypersensitivity reactions to allopurinol may be increased in patients with decreased renal function receiving thiazides and allopurinol concurrently. Such combinations should be administered with caution and patients should be observed closely.

Contraindications

APO-ALLOPURINOL should not be administered in individuals known to be hypersensitive to allopurinol or to any other ingredients of the product. APO-ALLOPURINOL should not be given concomitantly with iron salts to patients with idiopathic haemochromatosis, nor should it be given to the immediate relatives of such patients. APO-ALLOPURINOL is contraindicated in children with the exception of those with hyperuricaemia secondary to malignancy or with Lesch-Nyhan syndrome, because safety and efficacy have not been established in other conditions.

Regulatory history

APO-ALLOPURINOL 300 mg tablet blister pack (ARTG 269638) and 100 mg tablet bottle (ARTG 269652) were first listed on the Australian Register of Therapeutic Goods on 22 February 2017.