SAN DIEGO — Cefazolin was associated with fewer adverse events and had similar efficacy compared with nafcillin for the treatment of methicillin-susceptible Staphylococcus aureus, according to data presented at ICAAC 2015.
“These results are important to the health care system because nafcillin can be up to 10 times the cost of cefazolin, and with continually rising health care costs and tight budgets, cheaper alternatives are necessary,” Maggie Monogue, PharmD, clinical pharmacy fellow at Hartford Hospital Center for Anti-Infective Research and Development, said in a press release.
During a press conference, Monogue and Jessica Ortwine, PharmD, from Parkland Health and Hospital System, reported that infective endocarditis guidelines recommend cefazolin as an alternative to nafcillin for patients with a penicillin allergy. Previous studies demonstrated that cefazolin may result in higher treatment failure rates due to specific enzymes associated with the agent. However, retrospective data from prior studies that compared nafcillin with cefazolin showed similar efficacy between the antibiotics.
To clarify these findings, researchers conducted a retrospective, noninferiority study comparing data from 142 patients hospitalized with MSSA bacteremia who either received cefazolin (n = 71) or nafcillin (n = 71) for at least 72 hours.
The treatment failure rate — defined as switching antibiotics due to adverse events or a lack of clinical improvement, MSSA-related relapse within 90 days or mortality within 30 days — for patients who received nafcillin was 14% compared with 8.4% among patients assigned cefazolin. Of note, no treatment failures were reported in the cefazolin arm among patients with endocarditis, pneumonia, deep abscesses or osteomyelitis.
The researchers also found that nafcillin was associated with more adverse events than cefazolin (19.7% vs. 7%; P = .027).
“With nafcillin, we saw a significantly greater amount of nephrotoxic effects,” Mongue said during the conference. “This also has been seen in previous studies. Why that occurs is not completely 100% understood.”
Cefazolin was less expensive than nafcillin, and Monogue estimated that over the 3-year observation period, cost savings were almost $100,000 — money that could be applied to other resources, she said.
“These findings, coupled with cost savings involved with using cefazolin over nafcillin, make it an appealing first-line agent for most MSSA bloodstream infections,” Monogue said in the release. – by Stephanie Viguers
Monogue ML, et al. Abstract S-912. Presented at: Interscience Conference on Antimicrobial Agents and Chemotherapy; Sept. 17-21, 2015; San Diego.
Disclosures: Monogue and Ortwine report no relevant financial disclosures.