Allopurinol is a xanthine oxidase inhibitor used in the treatment of gout. Levels of allopurinol and oxypurinol in urine are useful for confirming adherence.
Monitoring adherence in patients treated for gout, HPRT deficiency or APRT deficiency. The test also measures urinary purine levels. In patients with purine overproduction due to HPRT deficiency, levels of insoluble xanthine in urine should be monitored, and if above the limit of solubility, the dose of allopurinol reduced to minimise the risk of a xanthine nephropathy. Allopurinol is also used in the treatment of APRT deficiency to prevent the formation of insoluble 2,8-dihydroxyadenine.