Pharmacokinetics of oxycodone after intravenous and subcutaneous administration in Japanese patients with cancer pain.

ABSTRACT In Japan, Oxycodone hydrochloride injection formulation has been approved in 2012. However, its pharmacokinetics has been poorly studied. The aim of this study is to evaluate the pharmacokinetics of oxycodone after intravenous and subcutaneous administration of oxycodone hydrochloride injection in Japanese patients with cancer pain. Noncompartmental analysis and population pharmacokinetic analysis were performed. We conducted a multicenter open-label study of oxycodone hydrochloride administered as constant infusion with the dose titrated individually according to the pain intensity in patients with cancer pain. Pharmacokinetic parameters for plasma oxycodone and its metabolites were estimated using pharmacokinetics of oxycodone was evaluated using a total of 344 plasma concentrations obtained from 89 patients. The estimated geometric mean clearance (CL) of oxycodone was 24.3 L per hour after constant intravenous infusion and 29.5 L per hour after constant subcutaneous infusion, respectively. Population pharmacokinetic analysis indicated that body surface area was the influencing factor on CL and there were no pharmacokinetic differences for CL between intravenous and subcutaneous infusion. These results provide important information for the clinical use of oxycodone injection.