Individuals who have kidney disease or other ailments who regularly take aspirin or acetaminophen may be boosting their risk of developing kidney failure.

Researchers report that such patients who were regular users -- those who took these painkillers at least twice a week for 2 months -- were two to three times more likely to have the beginning stages of chronic kidney failure, compared with individuals who did not use these painkillers on a regular basis.

This study and others have found that the risk is minimal in those without pre-existing kidney disease.

Individuals who used either drug regularly were 2.5 times more likely to be diagnosed with chronic renal failure, compared with individuals who did not use these painkillers. The risk rose in tandem with the amount of either drug taken over a lifetime, the investigators found.

In looking at only participants with diabetes -- a major underlying cause of kidney failure -- regular aspirin and acetaminophen use were still linked to an increased risk.

The results support those of other studies that have found an association between regular use of painkillers and an increased risk of chronic kidney failure in susceptible individuals.

The results are consistent with exacerbating effects of acetaminophen and aspirin on chronic renal failure, practically regardless of accompanying disease.

The New England Journal of Medicine December 20, 2001;345:1801-1808