Cefazolin pharmacokinetics

The renal clearance of the drug is proportional to endogenous creatinine clearance, irrespective of the mechanisms (i.e., filtration, reabsorption, or secretion), and the creatinine clearance is used as an indicator of the severity of the disease. Furthermore, it is possible to predict the half-life of a drug in a patient with renal disease based on the creatinine clearance and on a knowledge of the pharmacokinetics of the drug in normal subjects, as illustrated with cefazolin in Fig. 3. 

Tosukhowong T, Eiam-Ong S, Thamutok K, Wittayalertpanya S, Na Ayudhya DP. Pharmacokinetics of intraperitoneal cefazolin and gentamicin in empiric therapy of peritonitis in continuous ambulatory peritoneal dialysis patients. Peril Dial Int 2001 21(6) 587-94. 

Manley HJ, Bailie GR, Frye R, Hess LD, McGoldrick MD. Pharmacokinetics of intermittent intravenous cefazolin and tobramycin in patients treated with automated peritoneal dialysis. J Am Soc Nephrol 2000 11(7) 1310-16. 

Sams, R.A. Ruoff, Jr., W. W. (1985) Pharmacokinetics and bioavailability of cefazolin in horses. American Journal of Veterinary Research, 46, 348-352. 

In addition to the species and model differences in these two studies, only the latter was done following multiple dosing. These differences could be resolved by calculation of the appropriate pharmacokinetic parameters. Bergan has made such calculations for cefazolin and several other cephalosporins in humans and found cefazolin to be the drug of choice in distributing to tissue fluids. 0 This conclusion was based on the apparent volume of tissue compartment, calculated from V j (steady state) and a comparison of the magnitudes of the transfer rate constants ki2 (entry into tissue) and k2i (exit from tissue). Of the cephalosporins studied, only cefazolin had a ratio greater than unity,... 

Barza M, Kane A, Baum J. Pharmacokinetics of intravitreal carbenicillin, cefazolin and gentamicin in rhesus monkeys. Invest Ophthalmol Vis Sci 1983 24 1602-1606. 

No interaction normalfy occurs between digoxin and amoxicillin, cefazolin, cefuroxime, flucloxacillin, phenoxymethylpenicillin or ticarcillin/clavulanic acid. No pharmacokinetic interaction occurs between ampicillin and digitoxin. In contrast, one early study found that cefradine increased serum levels of digoxin. 

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