[Pharmacokinetics of controlled-release oxycodone in patients with cancer pain].

Oxycodone is a useful analgesic for cancer patients in pain. However, its pharmacokinetics have not been sufficiently examined and there is a lack of information, with very few reports on pharmacokinetics concerning the absorption process in particular. With this in mind, we studied the pharmacokinetics of controlled-release oxycodone (Oxy contin). We measured its serum concentration in patients with cancer pain, and calculated parameters derived using the nonlinear least-squared method program (MULTI). In the result, pharmacokinetic parameters calculated at CL/F were: 45.6+/-22.0 L/hr (Mean+/-SD), Vd/F: 473.0+/-19 6.7 L, t(1/2): 7.2+/- 6.2 hr, kel: 0.103+/-0.034, kal: 1.082+/-0.604, Lag time: 0.9 9+/-0.40 hr. In addition, the serum oxycodone concentration hardly rose until 1 hour after and just before medication, whereupon a rapid increase was evident after 1 hour. The pharmacokinetics of controlled-release oxycodone in patients with cancer pain were clarified in this study. Especially during the absorption process, the lag time was calculated specifically at about 1 hour, making it approximately equal to MS contin.