Short-Term Use of Gentamicin Does Not Harm Kidneys, Study Finds

Short courses of gentamicin appear safe in patients with bacteremia, according to new research that examined whether the aminoglycoside would damage the kidneys if used for fewer than 3 days.

When used for long periods of time, aminoglycosides like gentamicin have been shown to be nephrotoxic. But the research regarding short-term use is less conclusive.

The discrepancies in previous research prompted investigators in Denmark to look more closely at the issue. For the retrospective, propensity score-matched study, the investigators focused on patients with bacteremia who stayed at a Danish hospital between 2010 and 2013 and received no more than 3 days of once-daily gentamicin doses. A total of 702 patients fit that description and were included in the study. These patients were compared with another 702 patients who did not receive gentamicin. All patients were tracked for renal function, renal recovery, and mortality.

The data showed gentamicin did not increase the risk of kidney problems.

“The reason why short courses of gentamicin are safe, is that it is the accumulated dose of gentamicin that determines the risk of nephrotoxicity,” study author Jonas Boel, PhD, MSc, of the University of Copenhagen, told Contagion®.

Dr. Boel said his study aligns with a 1998 study of aminoglycosides in elderly patients.

“Another older study investigated the effect of treatment length and risk of nephrotoxicity and found that treatment for up to 3 days was not linked to the adverse effect,” Dr. Boel said.

That study also found that shortening the course of aminoglycoside therapy significantly reduced the risk of toxicity in that vulnerable population.

In their study, Dr. Boel and colleagues used the Kidney Disease: Improving Global Outcomes (KDIGO) criteria to measure the impacts of gentamicin on kidney function. They found no significant variance between the rates of acute kidney injury in the gentamicin and nongentamicin cohorts, and a similar rate of renal function recovery in both groups. The 90-day all-cause mortality hazard ratio was 1.02.

In addition to administering gentamicin for 3 days or fewer, Dr. Boel said it is also important that the drug is given just once per day, instead of 3 times per day.

The study comes at a time when the use of gentamicin is increasing in Denmark, according to Dr. Boel.

“In Denmark, it is getting more popular, as a way to avoid using more broad-spectrum antibiotics,” he said, adding that he did not know whether the same trend was being seen in the United States. A 2016 study, however, found that the drug remained in wide use, primarily among young children and young adults.

If his study leads to an increase in the use of gentamicin, Dr. Boel said he hopes that it is done so with open eyes.

“...I hope it can help physicians to make a more informed decision regarding nephrotoxicity,” he said.

The study, “The effect of short-course gentamicin therapy on kidney function in patients with bacteraemia—a retrospective cohort study,” was published in the December issue of the European Journal of Clinical Microbiology and Infectious Diseases.