Relative potency of controlled-release oxycodone and controlled-release morphine in a postoperative pain model

Area of Science:

• Pharmacology
• Pain Management
• Clinical Trials

Background:

• Postoperative pain management often involves opioids.
• Understanding the relative potency of different opioid formulations is crucial for effective treatment.
• Controlled-release formulations offer sustained pain relief.

Purpose of the Study:

• To compare the relative analgesic potency of single doses of oral controlled-release oxycodone and oral controlled-release morphine.
• To establish a basis for converting between these opioid formulations.

Main Methods:

• A randomized, double-blind trial involving 169 women with moderate to severe postoperative pain.
• Administration of single oral doses of controlled-release oxycodone (20 mg or 40 mg) or controlled-release morphine (45 mg or 90 mg).
• Pain assessments conducted over 12 hours post-dosing.

Main Results:

• Controlled-release oxycodone demonstrated 1.8 times greater potency for total analgesic effect and 2.2 times greater potency for peak effect compared to controlled-release morphine.
• Comparable analgesic effects were observed between oxycodone 20 mg and morphine 45 mg, and oxycodone 40 mg and morphine 90 mg.
• Onset of analgesia occurred within 1 hour for most patients, with faster peak relief noted for controlled-release oxycodone at higher doses. Side effect profiles were similar for both opioids.

Conclusions:

• Oral controlled-release oxycodone is approximately twice as potent as oral controlled-release morphine.
• A recommended conversion ratio of 1:2 (oxycodone:morphine) is suggested when switching patients from oral morphine to oral oxycodone.
• This finding aids in optimizing opioid therapy and ensuring adequate pain control during transitions between formulations.