Pharmacokinetics and Clinical Evaluation of Imipenem/Cilastatin Sodium in Pediatric Surgery

Pharmacokinetic and clinical studies on imipenem/cilastatin sodium (IPM/CS) in pediatric surgery were performed and the results obtained are summarized below. 1. Plasma and urinary levels of IPM/CS were measured in 9 neonate patients following drip-infusion for 1 hour of IPM/CS (dose of IPM 10 mg/kg for 5 patients, 20 mg/kg for 4 patients). In the 10 mg/kg group, peak plasma levels were observed at the end of infusion or after 1 hour of it. IPM 9.95~14.2 μ g/ml, CS 7.7~30.1 μ g/ml. In the 20 mg/kg group, peak levels were found at the end of the infusion, IPM 39.2~41.7 μ g/ml, CS 48.1~58.8 μ g/ml. In both groups, plasma levels of IPM/CS decreased rapidly, and plasma half-lives (T 1/2) in the 20 mg/ kg group were 0.9~1.2 hours (IPM) and 0.8~1.1 hours (CS). Urinary recovery rates were 17.7~ 28.7% (10 mg/kg), 21.1~36.9% (20 mg/kg) for IPM and 27.1~43.8% (10 mg/kg) and 21.5~76.5% (20 mg/kg) for CS. 2. Bile levels of IPM/CS were measured in 3 patients with congenital biliary atresia and 1 patient with neonatal hepatitis. Peak levels of IPM/CS in bile were noted 1 hour after the end of infusion, and they were 3.01~12.3 μ g/ml for IPM, and 2.5~13.1 μ g/ml for CS. Recovery rates in bile in 7 hours after the end of infusion were 0.03~0.12% (IPM), 0.01~0.12% (CS). 3. IPM/CS was administered to 9 patients as prophylaxis against postoperative infections and to 2 patients with postoperative cholangitis. No infectious complications were observed in patients after the prophylactic use. In 1 patient with cholangitis, clinical effect was good and organisms were eradicated. No clinical or laboratory adverse reactions due to the administration of IPM/CS were noted. It is concluded that IPM/CS is an effective and safe antibiotic in pediatric surgery.