The drug allopurinol does not slow the rate of worsening kidney disease, despite being used in up to 20% of kidney patients, a clinical trial has found.

Allopurinol is known to be effective in treating gout, the painful condition of high urate levels often linked to renal failure. But investigators were surprised to find that it has no effect on kidney disease progression when compared to placebo, reported Professor David Johnson, medical director of Queensland Renal Transplant Service, Australia, and colleagues.

The widely held view that elevated blood urate levels are responsible for rapid kidney function decline may well be wrong, the researchers said.

“Based on our study results, it appears that elevated blood urate levels are most likely an indicator of reduced kidney function rather than a cause of reduced kidney function,” said Associate Professor Sunil Badve, a nephrologist from The George Institute for Global Health.

“[W]e believe there is no benefit in prescribing this medication unless there is an additional specific medical reason, such as gout,” Johnson said. 

“It is important, though, that people with kidney disease who are already taking a medication like allopurinol to lower blood urate levels don’t abruptly stop this treatment,” he added. “They should discuss their kidney care management with their doctor first.”

The two-year study involved 31 hospitals in Australia and New Zealand, and more than 360 patients with stage three or four chronic kidney disease. Participants were all at increased risk of further renal failure.

The study was published in The New England Journal of Medicine.