Imipenem Monohydrate

Imipenem (N-Formimidoyl thienamycin) (MK-0787) is a new beta-lactam carbapenem antibiotic. When it is combined with the renal dipeptidase inhibitor cilastatin (MK-0791) the combination is known as primaxin. In this study 28 adult patients (24 males and 4 females) with acute bacterial pneumonia were treated with primaxin. Twenty-one patients were evaluable and 20 (95%) were clinically cured of their pneumonia. Bacteriological cures were demonstrated in 84% of the cases. One patient with a susceptible Pseudomonas aeruginosa failed. Major complications or toxic reactions included antibiotic associated diarrhoea in one patient; hypotension in one patient; increased grand mal seizures in one patient and elevated liver function studies in one patient. Results of this study suggest that primaxin will be useful in the treatment of a variety of serious Gram-positive and Gram-negative pneumonias. The true incidence of possible toxic reactions with this drug is not known at this time and awaits further experience.

Fundamental and clinical studies on imipenem/cilastatin sodium (MK-0787/MK-0791) were performed in pediatric patients with infections. Results obtained were summarized below. The mean plasma half-life of MK-0787 was 0.84 hour with a dosage of 10 mg/kg and 0.90 hour with a dosage of 20 mg/kg. Mean plasma half-lives of MK-0791 were 0.40 hour and 0.71 hour for dosages of 10 mg/kg and 20 mg/kg, respectively. Urinary recovery of both MK-0787 and MK-0791 was high. The antibacterial activity of MK-0787 against clinically isolated organisms was determined. The MK-0787 was bactericidal against a broad spectrum of both Gram-positive and Gram-negative pathogens. The MK-0787/MK-0791 was administered to 32 pediatric patients with various infections. The overall clinical efficacy rate was 96.9%. Side effects observed were loose stools in one patient, diarrhea in another and slight elevations of platelet and direct bilirubin, and eosinophilia were observed in 3 patients, respectively.

Fundamental and clinical studies were performed on a newly developed carbapenem antibiotic, imipenem/cilastatin sodium (MK-0787/MK-0791), and results were summarized as follows. The antibacterial activity of MK-0787 at an inoculum of 10(6) cells/ml against strains of S. aureus which were sensitive or resistant to cefazolin (CEZ), E. coli, P. mirabilis, K. pneumoniae, S. marcescens and P. aeruginosa were determined and compared with activities of ceftazidime (CAZ), CEZ, cefmetazole (CMZ), ceftizoxime (CZX), latamoxef (LMOX), cefamandole (CMD), cefoperazone (CPZ), cefsulodin (CFS) and piperacillin (PIPC). The peak MIC of MK-0787 was less than or equal to 0.024 micrograms/ml against S. aureus, which were sensitive or resistant to CEZ, 0.10 micrograms/ml against E. coli, P. mirabilis, or K. pneumoniae, 0.39 micrograms/ml against S. marcescens and 1.56 micrograms/ml against P. aeruginosa. The antibacterial activity of MK-0787 against these bacteria was, on the whole, superior to that of CAZ, CEZ, CMZ, CZX, LMOX, CMD, CPZ, CFS or PIPC. The pharmacokinetics of MK-0787/MK-0791 was studied in 10 children at dose levels of 10 mg/10 mg/kg and 20 mg/20 mg/kg by a 30-minute intravenous drip infusion.