Effects of Frusemide on uric acid and oxypurinol in patients with gout

An audit undertaken by Drs Stamp and Gow at Middlemore hospital showed that many patients were taking higher than recommended doses of allopurinol. Despite this many patients failed to achieve a low level of serum urate. While there was a correlation between renal function and plasma oxypurinol levels (the measurable breakdown product of allopurinol), there was no correlation between plasma oxypurinol and serum urate. Although the numbers from this audit were small it suggested that additional urate lowering did not occur with oxypurinol concentrations >100mmol/l. This pilot study aims to expand on the results of this audit by examining whether additional urate reduction can be achieved by increasing the dose of allopurinol in those with a low plasma oxypurinol concentration without an increase in adverse events.