Population pharmacokinetics and analgesic potency of oxycodone

Area of Science:

• Pharmacology
• Anesthesiology
• Clinical Pharmacy

Background:

• Intravenous oxycodone is frequently used for postoperative pain management.
• Characterizing its pharmacokinetic and pharmacodynamic properties is essential for effective dosing.
• Specific concentration thresholds for analgesia in major open intra-abdominal surgery are not well-defined.

Purpose of the Study:

• To characterize the population pharmacokinetics of intravenous oxycodone.
• To determine the minimum effective concentration (MEC) and minimum effective analgesic concentration (MEAC) of oxycodone for major open intra-abdominal surgery.

Main Methods:

• A prospective study involving population pharmacokinetic analysis and an analgesic-potency study.
• Patients received intravenous oxycodone (0.1 mg/kg).
• Pain was assessed using a visual analogue scale, with blood samples collected to determine MEC and MEAC at specific pain thresholds.

Main Results:

• Population pharmacokinetics were described by a three-compartment model, with lean body mass and age as covariates.
• Median MEC ranged from 31.5 to 63.4 ng/mL, and median MEAC ranged from 74.1 to 76.1 ng/mL.
• The study identified specific MEC and MEAC values for oxycodone in this surgical population.

Conclusions:

• The minimum effective analgesic concentration (MEAC) for intravenous oxycodone in major intra-abdominal open surgery is approximately 75 ng/mL.
• The analgesic potency (MEC) was found to be around 60 ng/mL.
• These values can guide titration strategies for effective postoperative pain control.