Indications: gout prophylaxis, hyperuricaemia

Cautions: administer prophylactic colchicine or NSAID (not aspirin or salicylate) until at least 1 month after hyperuricaemia corrected; ensure adequate fluid intake (2 liters/day); render urine alkaline if uric acid overload is high; caution in hepatic disease; reduce dose in renal impairment (in renal failure adjustment of dosage is necessary during dialysis). In neoplastic conditions, treatment with allopurinol (if required) should be commenced before cytotoxic drugs are given; pregnancy and breast-feeding.

Contra-indications: not a treatment for acute gout; if patient is receiving allopurinol when attack occurs continue as normal and treat attack separately.

Side Effects: rashes, fever (withdraw therapy). If the rash is mild the drug can be re-introduced with caution and discontinued immediately if rash recur; malaise, vertigo, headache, symptomless xanthine deposits in muscle, alopecia, hepatotoxicity.

Drug Interactions: Anticoagulants—Allopurinol may increase the chance of bleeding; Azathioprine or Mercaptopurine Allopurinol may cause higher blood levels of azathioprine or mercaptopurine.

Dose: initially, 100mg daily as a single dose, after meals

gradually increased over 1-3 weeks according to the plasma or urinary uric acid concentration, to about 300mg daily.

Usual maintenance dose, 200-600mg, rarely 900mg daily, divided into doses of not more than 300mg.

Child, (in neoplastic conditions, enzyme disorders), 10- 20mg/kg daily.

Breast feeding: Allopurinol passes into the breast milk