cilastatin--imipenem-drug-combination and Body-Weight

Observations on 1,754 patients treated with imipenem/cilastatin in phase III dose-ranging studies in the United States were reviewed to determine risk factors for seizures. The patients were moderately to severely ill with numerous background disorders known to be associated with an increased risk of seizures. Fifty-two patients (3 percent) had seizures and in 16 (0.9 percent) of them the seizures were judged by the investigators to be possibly, probably, or definitely related to imipenem/cilastatin. An incidence of seizure of 2 to 3 percent was noted among patients treated with other antibiotics (usually including a beta-lactam in the regimen) at times when imipenem/cilastatin was not being given. The average time of onset of seizures for patients receiving imipenem/cilastatin was seven days after start of therapy. As with other beta-lactam antibiotics, central nervous system lesions and disorders including seizures and renal insufficiency were found to be strong risk factors for seizures. Imipenem/cilastatin dosages in excess of those currently recommended by the manufacturer, particularly in patients with renal insufficiency, were also associated with an increased risk of seizures. There was an association with Pseudomonas aeruginosa infection that remained statistically significant even after controlling for imipenem/cilastatin dosage as well as for the other factors indicated. A high background incidence of seizures in general in a group of severely ill patients makes it both difficult to assess the etiology of a seizure and important to consider the risk factors when choosing the appropriate dose of an antibiotic. Guidelines are presented for appropriate dosing of imipenem/cilastatin in relation to renal function, body weight, and infecting pathogen.

Topics: Anti-Bacterial Agents; Bacterial Infections; Body Weight; Central Nervous System Diseases; Cilastatin; Cilastatin, Imipenem Drug Combination; Clinical Trials as Topic; Cyclopropanes; Drug Combinations; Female; Humans; Imipenem; Kidney Function Tests; Male; Regression Analysis; Retrospective Studies; Risk Factors; Seizures; Thienamycins; Time Factors; United States

The nephrotoxicity of vancomycin and cisplatin and the protective effects of fosfomycin and imipenem-cilastatin on renal function have been studied in rats. The renal clearance of vancomycin after the induction of renal dysfunction was also evaluated by calculating the glomerular filtration rate (GFR) and its secretory clearance. Plasma concentrations of creatinine and urea nitrogen increased dose-dependently after vancomycin injection. No such increases were observed after co-treatment with fosfomycin or imipenem-cilastatin. Changes of N-acetyl-beta-D-glucosaminidase activity in the urine of vancomycin-treated rats were not remarkable compared with those in cisplatin-treated animals. The reduced renal clearance of vancomycin in rats with acute renal failure induced by vancomycin was because of a decrease in both GFR and secretory clearance. However, the changes in GFR and secretory clearance were not proportional-the change in GFR was more pronounced than that of secretory clearance in the experimental groups. In addition, the renal clearance of vancomycin was maintained at the control level after co-administration of fosfomycin or imipenem-cilastatin with vancomycin. These results suggest that vancomycin impairs glomerular filtration more markedly than renal tubular function as compared with cisplatin. Co-administration with fosfomycin or imipenem-cilastatin confers significant protection against the nephrotoxic effects of vancomycin.

Topics: Acetylglucosaminidase; Animals; Anti-Bacterial Agents; Antineoplastic Agents; Body Weight; Cilastatin; Cilastatin, Imipenem Drug Combination; Cisplatin; Creatinine; Dose-Response Relationship, Drug; Drug Combinations; Fosfomycin; Glomerular Filtration Rate; Imipenem; Kidney; Male; Nitrogen; Rats; Rats, Wistar; Vancomycin; Weight Gain