title: Clearance of iopamidol, a non-ionic contrast medium, by CAPD in patients with end-stage renal failure.
abstract: In normal healthy subjects radiographic contrast media are cleared by the kidneys with a half-life of approximately 2 h and a total body clearance of 8 l/h. The mechanism of contrast clearance has not been previously investigated in chronic renal failure patients undergoing continuous ambulatory peritoneal dialysis (CAPD). A study was undertaken to investigate the pharmacokinetics of a non-ionic water soluble radiographic contrast medium (iopamidol) in 10 patients stabilized on CAPD. All patients (eight male, two female) aged 22-68 years (median 53 years) had injection of 30 ml of iopamidol 300 via a forearm vein to investigate subclavian vein patency following previous cannulation for haemodialysis. Venous blood samples, CAPD dialysate and urine were collected for seven days post injection. The mean plasma half-life was 37.9 h (SD 10.6) (range 24.1-57.2 h) for the CAPD patients and was greatly prolonged in comparison to healthy subjects. The total body clearance of iopamidol was also greatly reduced (0.377 l/h). CAPD removed an average of 53.6% of the administered dose (range 36.3-80.8%) whilst an average of 26.9% was excreted in the urine (range 1.3-56.3%). The combined renal and dialysate clearance was up to 93% of the administered dose over the period of the study. There is therefore some evidence for a small extra renal clearance of iopamidol in end-stage renal failure patients. This study has shown for the first time that patients with end-stage renal failure undergoing CAPD have significantly delayed elimination of contrast medium. This should be taken into consideration when extensive or prolonged investigations using contrast medium are proposed.
authors.affiliation: Department of Surgery, Leicester General Hospital, UK.
authors.forename: P K
authors.initials: PK
authors.lastname: Donnelly
authors.forename: N
authors.initials: N
authors.lastname: Burwell
authors.forename: A
authors.initials: A
authors.lastname: McBurney
authors.forename: J W
authors.initials: JW
authors.lastname: Ward
authors.forename: J
authors.initials: J
authors.lastname: Walls
authors.forename: E M
authors.initials: EM
authors.lastname: Watkin
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000493:pharmacokinetics*; D007668:Kidney / Q000378:metabolism; D007676:Kidney Failure, Chronic / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory
chemical_list: D007479:Iopamidol