Disposition of cefonicid in orthopedic surgery patients

Ten patients undergoing hip reconstructive procedures were given a single prophylactic dose of cefonicid 15 mg/kg to evaluate intraoperative and perioperative drug disposition in the surgical setting. Timed postinfusion serum samples were collected over 24 hours and resulting concentration versus time data were subjected to noncompartmental pharmacokinetic analysis. Bone samples were obtained in eight of ten patients with mean bone concentrations of 13.3 micrograms/g (range 8.2-25.1). Postinfusion serum concentrations at five minutes postinfusion ranged from 200.8 to 316.7 micrograms/ml; the 12-hour mean was 19.1 micrograms/ml (range 4.0-48) and the 24-hour mean was 4.3 micrograms/ml (range 0.0-13.8). Protein binding at three sampling times ranged from 88 to 96.5 percent, increasing over time as total cefonicid concentrations fell. The mean half-life in our patients was 3.5 hours, compared with 4.8 hours in our four controls. These data indicate that altered protein binding and intraoperative events alter the disposition of cefonicid. Although differences in disposition parameters between patients and controls were not statistically significant, suboptimal serum cefonicid concentrations were observed in four orthopedic patients.