Comparative Pharmacokinetics of Cefazolin, Cephalothin, Cephacetril, and Cephapirine after Intravenous Administration

Abstract

The pharmacokinetics of cephazolin given in intravenous dosages of 0.5 and 1.0 g and cephapirine, cephacetril and cephalothin in 1.0 g doses have been compared. The cefazolin appears to have favourable pharmacokinetic properties.

Absorption, Distribution and Elimination of Cefazolin in Patients with Normal Renal Function

“…Since few points were available for the k, estimation, it is im portant to note that the values were consis tent with the serum curve profiles observed during the first part of the observation peri od. Estimates of the lag-time revealed negli gible values in all patients, a finding that corresponds with earlier reports [2],…”

“…The fact that the distribution coefficient in this study is slightly higher than the / y derived from a previous intrave nous study [2] suggests incomplete absorp tion of cefazolin from an intramuscular de pot. Similar experience has been made with ampicillin [1].…”

“…These 4 patients had t'/2 values significantly above those observed in other studies [3,5,8], and also above the values of the other patients in this study ( p < 0 .0 1 ) . The lower mean t'/2 is of the same order as demonstrated previously in subjects with normal renal function [2,3,8]. The cause for the prolonged half-life in the 4 patients mentioned is not obvious.…”

“…When compared to previous studies on healthy volunteers [2], the present results suggest that the serum half-life of cefazolin is less predictable in bed-ridden patients suffering from infections. Nevertheless, it is significant that cefazolin was well tolerated by all patients [13].…”

“…The mean curve peak values in the two first cited works were 60 and 52.2 ± 25.4 //g/ml, respectively, as com pared to 69.2 ± 19.7,«g/ml in the present study. The cause of the higher serum con centrations found in our patients must be sought in their tV, values, which were some what higher than in previous studies of pa tients with uncompromised excretion capac ity [2,5]. Figure 1 shows The absorption constant after intramus cular administration has been derived from curve fitting of the data.…”