Establishment to measure oxycodone in plasma with liquid chromatography-tandem mass spectrometry.

Oxycodone (OXY) is classified as a "strong opioid" in the World Health Organization system of cancer pain treatment. However, OXY also causes severe adverse reactions, such as respiratory depression. Thus, in order to adjust the dosage of OXY for well-managed pain relief with less toxicity, we tried establishing and validating a system for measuring plasma concentrations of OXY using liquid chromatography-tandem mass spectrometry (LC-MS/MS).