Some Antibiotics May Injure Male Kidneys

Renal failure risks rise with antibiotics known as fluoroquinolones

(RxWiki News) Antibiotics fight off a broad range of bacterial infections. In middle-aged and older men, however, certain kinds of antibiotics may cause the kidneys to start shutting down.

A new study suggests that, for males aged 40 through 85, taking commonly prescribed antibiotics known as fluoroquinolones may more than double the risk of acute kidney injury that must be treated in a hospital.

"Ask your pharmacist about infection-fighting medications."

Steven T. Bird, PharmD, MS, a US Food and Drug Administration (FDA) researcher, was lead author of this study.

The researchers compared 1,292 patients taking either ciprofloxacin, gatifloxacin, gemifloxacin, levofloxacin, moxifloxacin or norfloxacin for skin, bone, joint, respiratory, gastrointestinal and other infections to 12,651 patients who were not taking those medications, which are part of a group of antibiotics known as fluoroquinolones.

The researchers selected their patients from a federal data bank of more than 68 million patients who filed prescription medication claims with their private insurers.

Men on dialysis or with a history of chronic kidney disease were excluded from the study, given that they already are susceptible to acute kidney injury.

The researchers found a two-fold spike in the risk for acute kidney injury among the 1,292 study participants. In addition, they found a four-fold increase in the risk for acute kidney injury among studied patients who were taking both the antibiotics and separate prescriptions to regulate blood pressure.

That injury, or renal failure, prevents the kidneys from doing their job of pushing out bodily wastes and toxins through urine, balancing body chemicals and helping stabilize blood pressure.

The study was prompted, in part, by many doctors' habit of prescribing fluoroquinolones without adequately considering the potential challenges they pose for patients, the researchers wrote.

“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 wrote.

Though there are additional fluoroquinolones, the researchers only included patients who were prescribed ciprofloxacin, gatifloxacin, gemifloxacin, levofloxacin, moxifloxacin and norfloxacin because those fluoroquinolones are taken by mouth and absorbed by the body quicker.

The medications have been credited for their fast absorption. Still, the FDA also has required drug-makers and pharmacists to list renal failure as a possible side effect on prescription medication labels.

While fluoroquinolones were a problem for some study participants, the researchers did not find higher risks for acute kidney injury among patients taking amoxicillin or azithromycin, two other commonly used antibiotics.

This study was published June 3 in the Canadian Medical Association Journal.

The research was funded by the McGill University Health Centre, Fonds de la Recherche en Santé du Québec and the Ministère de la Santé et des Services Sociaux in Canada and the US Agency for Healthcare Research and Quality.

No funders influenced the study, nor were involved in study design, the researchers reported.

The authors reported no financial investment or gain related to the study.

Review Date: 
May 29, 2013