Russo M E
Am J Hosp Pharm. 1980 May;37(5):702-4.
A case of a carbenicillin-tobramycin interaction resulting in laboratory test reports of subtherapeutic serum tobramycin levels in a 71-year-old man with renal failure is reported. The patient's Pseudomonas aeruginosa infection was treated with carbenicillin, 2 g every eight hours, and tobramycin, 80 mg after daily hemodialysis. The serum antibiotic levels were monitored using a microbiologic assay and a radioimmunoassay technique. At 30 minutes and five hours after the tobramycin was administered, microbiologic assay of serum levels indicated negligible tobramycin concentrations (2 micrograms/ml). Radioimmunoassay of tobramycin levels showed markedly higher concentrations (4.1 micrograms/ml at 30 minutes after infusion). The difference in assay results was attributed to greater inactivation occurring with the microbiologic assay, which was the less rapid technique. In vitro and in vivo factors influencing the occurrence and extent of the carbenicillin-tobramycin interaction are reviewed. When using an aminoglycoside-penicillin combination in patients with renal failure, it is important to use a rapid assay technique or one that inactivates one of the antibiotics before bioassay, and to be aware of the patient-related factors that can alter assay results.
报告了一例羧苄青霉素与妥布霉素相互作用的病例，该病例发生在一名患有肾衰竭的71岁男性身上，导致实验室检测报告显示血清妥布霉素水平低于治疗浓度。该患者的铜绿假单胞菌感染采用羧苄青霉素治疗，每8小时2克，妥布霉素在每日血液透析后使用80毫克。血清抗生素水平采用微生物学测定法和放射免疫测定技术进行监测。在给予妥布霉素后30分钟和5小时，血清水平的微生物学测定表明妥布霉素浓度可忽略不计（2微克/毫升）。妥布霉素水平的放射免疫测定显示浓度明显更高（输注后30分钟时为4.1微克/毫升）。测定结果的差异归因于微生物学测定中发生了更大程度的失活，该方法是速度较慢的技术。本文综述了影响羧苄青霉素与妥布霉素相互作用发生及程度的体外和体内因素。在肾衰竭患者中使用氨基糖苷类 - 青霉素联合用药时，重要的是使用快速测定技术或在生物测定前使其中一种抗生素失活的技术，并了解可能改变测定结果的患者相关因素。
