Pharmacokinetics of Cefmenoxime in normal and impaired renal function

7 beta-[2-(2-Aminothiazol-4-yl)-(Z)-2-methoxy-iminoacetamido]-3-[(1- methyl-1H-tetrazol-5-yl)thiomethyl]-ceph-3-em-4-carboxylic acid hemihydrochloride (Cefmenoxime), a new cephalosporin with a broad spectrum of activity against gram-positive and gram-negative bacteria, was investigated pharmacokinetically. 10 healthy volunteers and 20 patients with renal disease each received 2 g of the substance i.v. The plasma levels were monitored for 6 h in healthy volunteers and for 24 h in the patients with renal disease. The analysis of the data showed that the majority of the curves could be properly evaluated only with the aid of a two-compartment model. Therefore a simple half-life cannot be given. Cefmenoxime is eliminated more rapidly than cefoperazone, but more slowly than cefotaxime. The area under the serum level curves (AUC) increases when renal function is impaired. There is a mathematical correlation between the AUC and the renal function parameters, plasma creatinine and glomerular filtration rate. This gives the dose reduction factors, allowing the calculation of the doses with the same AUC on restricted renal function as that observed in healthy persons after normal doses. Dosage recommendations are given in the form of tables regarding the questions 1. to what extent the dose may be reduced in impaired renal function without lowering the AUC and 2. what is the highest safe dose.