The effect of obstruction on the biliary excretion of cefoperazone and ceftazidime

The biliary excretion of cefoperazone and ceftazidime was studied by endoscopic cannulation of the common bile duct, in patients with complete biliary obstruction and in an unobstructed control group. Patients were given each drug prophylactically for 24 h before endoscopy and as a single dose at the time of cannulation. In unobstructed patients biliary excretion of ceftazidime was passive. At the time of cannulation bile contained 10% of the peak serum concentration, rising to 20% 90 min later. Cefoperazone excretion was active. At cannulation biliary concentrations were 200% of the serum peak, 900% at 60 min and 700% at 90 min. In obstructed patients, bile sampled immediately at decompression contained neither antibiotic. Passive excretion of both drugs occurred rapidly after relief of obstruction and biliary concentrations were 20% of maximum serum levels at 60 min. Twenty-four hours later passive excretion had further improved, but the active excretion mechanism of cefoperazone had still not recovered. We conclude that obstruction impairs active as well as passive biliary excretion of antibiotics, that drainage is essential for the control of sepsis in obstructed cholangitis, and that both cefoperazone and ceftazidime achieve similar and therapeutic concentrations in bile during the 24 h after decompression.