A pharmacokinetic/pharmacodynamic study of controlled-release oxycodone

A single-dose, analytically blinded, randomized, crossover study was conducted in 22 healthy male volunteers to compare the bioavailability of one 20 mg with two 10 mg controlled-release (CR) oxycodone tablets. In addition, pharmacodynamic effects were assessed using both objective and subjective measures for up to 48 hs after dosing. The two treatments were bioequivalent, with comparable rates (C-max of one 20 mg tablet was 109% of two 10 mg tablets; 90% confidence limits: 98.4%-120%) and extents (AUC(0 infinity): 107%; 100%-114%) of absorption. In addition, no significant differences between tablets were found for mean values of T-max, T/12abs, or T1/2elim. Correlations between plasma oxcycodone concentrations and most pharmacodynamic measures were significant. The strongest correlations were observed for pupil size (r = -0.53) and subjects' assessment of drug effect (r = 0.53), with changes in plasma concentration accounting for more than 25% of the observed changes in these variables. This study demonstrated bioequivalence of two 10 mg and one 20 mg CR oxcycodone tablet, with significant correlation between plasma oxcycodone concentrations and pharmacodynamic effects in normal volunteers. (C) U.S. Cancer Pain Relief Committee, 1997.