Pharmacokinetics of cefoxitin administered intramuscularly to rabbits with experimentally-induced renal impairment

The pharmacokinetics of Cefoxitin were studied in rabbits with normal renal function and with varying degrees of renal impairment induced experimentally by uranyl nitrate. All animals received a single intramuscular (i.m.) dose of 40 mg kg-1 of the antibiotic. The concentrations of Cefoxitin were determined in plasma, urine, and bile by a microbiologic plate diffusion method. The antibiotic follows a two-compartment open kinetic model. In rabbits with renal impairment there is a decrease in alpha, beta, K12, K21, Ka and an increase in Vd and the (AUC)infinity zero with respect to the values obtained for rabbits with normal renal function. Linear relationships are established between log beta and log K13 and the serum creatinine. Biliary excretion of Cefoxitin is increased in states of renal impairment. A linear relationship is established between the percentage of the dose excreted in the bile and the serum creatinine.