The pharmacokinetics of oxycodone in uremic patients undergoing renal transplantation.

STUDY OBJECTIVE

To determine the pharmacokinetics of oxycodone and the excretion of oxycodone and its metabolites noroxycodone and oxymorphone in uremic patients undergoing renal transplantation.

DESIGN

Open study of the pharmacokinetics and excretion of oxycodone.

SETTING

IV Department of Surgery, Helsinki University Central Hospital.

PATIENTS

10 uremic patients undergoing renal transplantation and 10 ASA status I patients undergoing general surgery.

INTERVENTIONS

Intravenous (IV) oxycodone chloride 0.07 mg/kg was administered 30 minutes before induction of standardized anesthesia. Sampling of blood and urine was conducted for 24 hours.

MEASUREMENTS AND MAIN RESULTS

The concentrations of oxycodone and noroxycodone in plasma and the 24 hour urine recoveries of the conjugated and unconjugated forms of oxycodone, noroxycodone, and oxymorphone were measured. Mean elimination half-life was prolonged in uremic patients due to increased volume of distribution and reduced clearance. Interindividual variation was very great. Plasma concentrations of noroxycodone were higher in uremic patients. Significantly smaller quantities of free oxycodone and noroxycodone and both free and conjugated oxymorphone were excreted in the urine in the uremic than in the control patients.

CONCLUSIONS

Elimination of oxycodone is impaired in end-stage renal failure.