The Food and Drug Administration has issued an alert about a higher rate of deaths associated with the antibiotic linezolid in a recent study of patients with catheter-related bloodstream infections.
For patients infected with gram-positive organisms, there was no difference in death rates between patients on linezolid (Zyvox) and patients on a comparator antibiotic. “In contrast, mortality was higher in patients treated with linezolid who were infected with gram-negative organisms alone, with both gram-positive and gram-negative organisms, or who had no infection when they entered the study,” according to the FDA advisory.
Linezolid is not approved for treating catheter-related bloodstream infections, catheter-site infections, or for treating infections caused by gram-negative bacteria, the FDA cautioned.
The open-label trial enrolled 726 seriously ill patients aged 13 years and older with intravascular catheter-related bloodstream infections, including those with catheter-site infections. Almost half the patients were in an intensive care unit, and 26% were intubated. Patients were randomized to either linezolid 600 mg intravenously or orally every 12 hours, or to 1 g of vancomycin administered every 12 hours for 7–28 days. Those on vancomycin could be switched to oxacillin or dicloxacillin if the pathogen was methicillin susceptible, and could also receive concomitant therapy for gram-negative infections.
Up to 84 days after receiving the first dose of the drug, mortality was 21.5% in patients on linezolid and 16% in patients on a comparator antibiotic. In patients with gram-positive infections only, mortality was similar for patients on linezolid and those on a comparator (16.7% vs. 17.2%, respectively).
But among those with gram-negative organisms only, 27% of patients taking linezolid died, vs. 9% of those on a comparator. Among patients with gram-positive and gram-negative pathogens, 35% of those on linezolid died, vs. 18% of those on a comparator. Among patients with no infection at baseline, 26% of those on linezolid died, vs. 13% of those on a comparator.
The FDA cautioned that the advisory is based on a preliminary analysis of the data, and that the agency has not come to any final conclusions about the implications of this new study.
Information for health care professionals is available at www.fda.gov/medwatch/safety/2007/safety07.htm#Zyvoxwww.fda.gov/medwatch