Fluoroquinolones, including ciprofloxacin, levofloxacin and moxifloxacin, are common broad-spectrum antibiotics most often used to treat respiratory and urogenital infections. Case reports have indicated acute kidney injury with use, and prescription labels carry a warning of kidney failure. However, when oral fluoroquinolones are prescribed in clinical practice, kidney injury is usually not considered.

Researchers from the US and Canada undertook a study to determine the risk of acute kidney injury with the use of oral fluoroquinolones for adult men 40󈟁 years old enrolled in the US LifeLink Health Plan Claims Database between 2001 and 2011. There were 1292 cases of acute kidney disease and 12 651 controls in the study. Researchers excluded people who had a history of chronic kidney disease or dialysis because they can increase the risk of acute injury. They found that current use of oral fluoroquinolones increased the risk of acute kidney injury; the risk was highest with ciprofloxacin, followed by moxifloxacin. Past use did not increase the risk nor did the use of amoxicillin or azithromycin. They also found that concurrent use of an oral fluoroquinolone and a renin-angiotensin-system blocker, a popular class of cardiovascular medication, increases the risk of acute renal failure by 4.5 fold.

"We found a twofold increased risk of acute kidney injury requiring hospital admission with the use of fluoroquinolone antibiotics among adult men, using 2 analytic techniques," writes Dr. Mahyar Etminan, of the Child & Family Research Institute, Department of Pediatrics, University of British Columbia, and the Provincial Health Services Authority, with coauthors.

"The twofold differential in risk in current users suggests that acute kidney injury secondary to fluoroquinolone use is an acute adverse event."

The authors suggest that physicians need to be aware of the risks of kidney injury when prescribing these drugs. "Although it is clear that the risk of death due to serious infections outweighs the risks associated with the use of fluoroquinolones, the potential for acute kidney injury raises the importance of vigilant prescribing," they conclude.