Pharmacokinetics and ventilatory effects of oxycodone before and after liver transplantation

The pharmacokinetics and ventilatory effects of oxycodone were studied in six volunteer patients with end-stage liver cirrhosis before and after orthotopic liver transplantation. Plasma samples and urine were collected for 24 hours after intravenous administration of 0.05 mg/kg oxycodone hydrochloride. Concentrations of oxycodone and its metabolites, noroxycodone and oxymorphone, were measured in plasma and urine. THe median elimination half-life of oxycodone was 13.9 hours (range, 4.6 to 24.4 hours) in patients with cirrhosis before transplantation and 3.4 hours (range, 2.6 to 5.1 hours) after transplantation (p < 0.05). Correspondingly, oxycodone clearance increased from 0.26 L/min (range, 0.15 to 0.73 L/min) before transplantation to 1.13 L/min (range, 0.71 to 3.98 L/min) after transplantation (p < 0.05). Oxycodone depressed ventilation more strongly before transplantation than after transplantation (p < 0.05). Care should be exercised when oxycodone is used in patients with end-stage disease.