Biliary tract excretion of cefazolin, cephalothin, and cephaloridine in the presence of biliary tract disease.

The biliary tract excretion of three cephalosporins, cefazolin, cephaloridine, and cephalothin, was compared in patients with biliary tract disease. In the absence of obstruction, mean antibiotic levels in bile from gall bladder and common duct in patients undergoing cholecystectomy were highest for cefazolin (17 and 31 mug/ml, respectively) than either cephaloridine (7 and 9 mug/ml) or cephalothin (1 and 4 mug/ml). Biliary tract levels generally paralleled serum levels. In no patient with cystic duct obstruction were any of the cephalosporins detectable in appreciable amounts in gall bladder bile. In patients with T-tube drainage given each of the three different cephalosporins on separate days, concentrations of cefazolin in bile were many-fold higher than either cephaloridine or cephalothin. Peak levels of cefazolin in T-tube bile averaged 51 mug/ml after intravenous and 26 mug/ml after intramuscular administration, whereas mean peak levels of cephalothin and cephaloridine were only 6 and 16 mug/ml, respectively. Here, too, T-tube levels reflected serum concentrations and obstruction to biliary flow impaired excretion of each of the drugs.