The Pharmacokinetics of Oxycodone

Oxycodone is among the most commonly used opioid analgesics for the relief of moderate-to-severe pain and is pharmacodynamically comparable to morphine. Oxycodone is available in the United States in oral dosage forms and controlled-release tablets. Studies have demonstrated marked interindividual variation in the pharmacokinetics of oxycodone. The pharmacokinetics of oral oxycodone differs from oral morphine in that it has a higher bioavailability, a slightly longer half-life, and is hepatically metabolized by cytochrome P450 rather than undergoing glucuronidation. Understanding oxycodone pharmacokinetics favors safe and effective use of this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and May 2004 relevant to the pharmacokinetics of oxycodone. These publications were reviewed and the literature summarized regarding unique and clinically important elements of oxycodone disposition including its absorption profile (immediate release, controlled release, rectal administration, and intranasal administration), distribution, and its metabolism/excretion. Special populations, including children and those with liver/renal failure, have a unique oxycodone pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.