A PHARMACOKINETIC PHARMACODYNAMIC STUDY OF CONTROLLED-RELEASE OXYCODONE/

A single-dose, analytically blinded, randomized, crossover study was c onducted 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 objecti ve and subjective measures for up to 48 hs after dosing. The two treat ments were bioequivalent, with comparable rates (C-max of one 20 mg ta blet was 109% of two 10 mg tablets; 90% confidence limits: 98.4%-120%) and extents (AUC(0 infinity): 107%; 100%-114%) of absorption. In addi tion, no significant differences between tablets were found for mean v alues of T-max, T/12abs, or T1/2elim. Correlations between plasma oxcy codone concentrations and most pharmacodynamic measures were significa nt. 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 chan ges 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.