NEW YORK (Reuters Health) – Initial low-dose gentamicin given as part of the treatment for Staphylococcus aureus bacteremia and endocarditis can cause kidney dysfunction and should not be routinely used, according to a report in the March 15th issue of Clinical Infectious Diseases.

In an international study of 236 patients with S. aureus bacteremia and native valve endocarditis, decreased creatinine clearance was seen in 22% of patients treated with low-dose gentamycin versus just 8% of patients who were managed without the drug (p = 0.005).

Multivariate analysis confirmed that gentamycin use, along with age over 64 years, were independent predictors of decreased creatinine clearance.

The subjects were randomized to either standard therapy with anti-staphylococcal penicillin or vancomycin, plus low-dose gentamycin in all but seven cases, or to daptomycin monotherapy, lead author Dr. Sara E. Cosgrove, from The Johns Hopkins Hospital, Baltimore, and colleagues explain. Before study enrollment, 21 patients in the daptomycin arm and 22 in the standard therapy arm received initial low-dose gentamycin.

Overall, 19% of vancomycin recipients, 17% of penicillin recipients, and 7% of those given daptomycin experienced an adverse renal event. The corresponding rates of decreased creatinine clearance were 22%, 25%, and 8%.

Summing up, the researchers write: “Clinically significant decreases in creatinine clearance occurred earlier and were sustained through the end of therapy in patients who received initial low-dose gentamycin than in patients who received no gentamycin. None of the 7 patients who received standard therapy alone experienced a decrease in renal function.”

They conclude, “On the basis of evidence of potential harm and the lack of evidence for clinically significant benefit, we recommend against the routine use of initial low-dose gentamicin in the management of most cases of S. aureus bacteremia and native valve endocarditis, particularly in elderly and diabetic patients and in patients with even mild baseline renal dysfunction.”

Reference:
Clin Infect Dis 2009;48:713-720.