Effects of biliary obstruction on the penetration of ciprofloxacin and cefotaxime.

Objective To evaluate the biliary penetration of ciprofloxacin and cefotaxime in patients with obstructed bile ducts and to determine simple predictive markers of effective biliary concentrations of these drugs. Methods Sixty-two patients treated with endoscopic biliary drainage were prospectively included in a nonrandomized way and received intravenous ciprofloxacin (200 mg twice daily) or cefotaxime (1 g three times a day) for more than 24 h before exploration. Blood and bile samples were collected at the time of drainage. Ciprofloxacin and cefotaxime concentrations were measured using high-performance liquid chromatography. Biliary penetration was assessed by the bile-to-plasma ratio of the concentrations of both antibiotics. Results Biliary penetration ranged from 0.06 to 42.7 for ciprofloxacin and from 0.01 to 1.14 for cefotaxime. The ratio was more than one in only 10 patients (35%) and three patients (9%) in ciprofloxacin and cefotaxime groups, respectively. Biliary concentration of the drug was more than 10 times the minimal inhibitory concentration in only 10 patients (35%) and in 12 patients (35%) in ciprofloxacin and cefotaxime groups, respectively. Serum bilirubin, alkaline phosphatase or gamma-glutamyl-transpeptidase were not good predictive markers of the biliary diffusion of the antibiotics. Conclusion In patients with obstructed bile ducts, the biliary penetration of ciprofloxacin is poor and reaches effective biliary concentrations in a minority of patients. Cefotaxime biliary penetration is even poorer. No liver test can predict accurately the biliary penetration of the drugs.