Pharmacokinetics of azosemide in patients with T-drain after cholecystectomy

In an open clinical trial the pharmacokinetics of orally administered azosemide (2-Chloro-5-(1H-tetrazol-5-yl)-4-[(2- thienylmethyl)amino] benzene sulfonamide. Luret, CAS 27589-33-9) was surveyed in a group of 10 patients with T-drain after cholecystectomy. The mean peak concentration was reached after 2.35 h (SE: 0.25 h) and was 474 ng/ml (142 ng/ml). The plasma elimination half-life was estimated to be 6.37 h (1.7 h). In 24 h 5.4% of the dose was excreted unchanged via urine and bile. Only a small fraction of the dose (0.53%) was recovered as glucuronide from urine and bile. Approximately 2% (0.74%) of the dose was excreted unchanged via bile. No other metabolites were detected. Plasma AUCO-24h was 3113 micrograms.h/l. The renal clearance of 27 ml/min (8.8 ml/min) was 3 times higher than the biliary clearance of 10 ml/min (2.4 ml/min). Azosemide is rapidly but incompletely absorbed and shows a longer half-life when compared with other loop diuretics. Enterohepatical circulation and first-pass effect seem to be less significant because low amount of azosemide is excreted via bile.