While the cost for Zyvox was far greater than vancomycin, a drug that has been in use for nearly 50 years as a last resort for bacterial infections, the associated costs of treatment - such as placement of intravenous lines and extra home and hospital visits to perform the infusions -- made up the cost difference and more, Dr. Liu reported.

A major difference in costs between the 2 drugs was rehospitalizations. The average patient on vancomycin therapy spent $5,716 on hospital visits during the 35 days after the start of therapy while the Zyvox patients spent $3,945 on rehospitalization costs.

Overall, Zyvox outpatient treatment cost an average $8,922 while vancomycin outpatient IV treatment cost $13,552 per patients. Dr. Liu said the difference was statistically significant at the P < .0001 level.

Lead investigator Peggy McKinnon, PharmD, clinical pharmacist, Barnes-Jewish Hospital, St. Louis, Missouri, said, "This new information broadens our understanding of the benefits of oral linezolid. Using an oral agent eliminates the risk of intravenous complications, such a line infections, as well as the cost of intravenous administration. The study offers further evidence of the costs savings of oral linezolid to the health care system."

"Even though Zyvox is one of our most expensive antibacterial drugs, the costs for outpatient therapy is less expensive with Zyvox due to all the other costs associated with intravenous administration of vancomycin," said David Gilbert, MD, a former president of the IDSA and professor of medicine, Oregon Health Sciences University, Portland, Oregon. Dr. Gilbert was not involved with the study.

"Both patients and doctors prefer the oral medication," he said, but noted that the bottom line is whether Zyvox works as effectively as vancomycin in eradicating stubborn infections. "We have a long track history with vancomycin," he added. Dr. Gilbert said studies are underway comparing the efficacy of the 2 drugs.

In the study, Dr. Liu and colleagues extracted longitudinal claims data from more than 80 healthcare plans, seeking a retrospective cohort of adult patients with a pharmacy claim for Zyvox or vancomycin. Out of the 43 million unique subjects in the database, the researchers found 1048 patients for each of the 2 groups.

They found that oral Zyvox cost about $1,485 per patient for the 35-day period, while vancomycin costs were estimated at about $200 for the same time frame. But the other costs -- such as testing for adequate levels of vancomycin, checking kidney function -- overcame that pharmacy difference.

"Oral Zyvox provides for an opportunity to treat patients with infection in a less expensive setting than intravenous vancomycin, and is associated with a lower overall cost of care," Dr. Liu said.


[Presentation title: Impact of Oral Linezolid Vs. IV Vancomycin on Resource Utilization and Cost in the Outpatient Setting. Abstract 450]

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