Pharmacokinetics of ampicillin/sulbactam in patients undergoing spinal microneurosurgical procedures

The fixed combination of ampicillin (2 g)/sulbactam (1 g) was administered as perioperative prophylaxis at induction of anesthesia in 20 patients undergoing spinal microneurosurgery. It was noteworthy that after the short infusion ampicillin and sulbactam penetrated rapidly from blood into the different tissues affected by the surgical procedures. The following mean concentrations were measured in tissues: muscle 32.3+/-6.5 mg/kg ampicillin and 18.6+/-2.9 mg/kg sulbactam (11.1 min), ligament 39.5+/-11.1 mg/kg ampicillin and 25+/-6.5 mg/kg sulbactam (13.8 min), bone 12+/-3.6 mg/kg ampicillin and 7+/-0.8 mg/kg sulbactam (20.6 min), disk 10.2+/-3.3 mg/kg ampicillin and 7.3+/-1.8 mg/kg sulbactam (44.2 min). The mean time of sampling is given in brackets. For a period of at least 2 h the levels of both drugs measured in serum and in the different tissues were above the MICs for bacteria involved in postoperative wound infections. The administration of ampicillin/sulbactam apparently achieved sufficiently, high antibiotic concentrations, even in bradytrophic tissues such as ligament, bone, and disk, and seemed to meet the pharmacological criteria for perioperative prophylaxis in spinal microneurosurgery.