Naltrexone Administration and Perioperative Considerations

Introduction to Naltrexone

The American College of Physicians recommends holding oral naltrexone for 2-3 days prior to elective surgical procedures if opioids are expected to be used perioperatively, due to its opioid antagonist properties that can block analgesic effects and potentially precipitate withdrawal 1, 2
Naltrexone is a semisynthetic competitive opioid receptor antagonist with a plasma half-life of 4 hours, while its active metabolite (6-β-naltrexol) has a half-life of 13 hours 1

The American Society of Anesthesiologists recommends holding oral naltrexone for 2-3 days prior to elective surgical procedures if opioids are expected to be used perioperatively 1, 3
For extended-release injectable naltrexone, hold for 24-30 days after the last injection before elective surgical procedures 1, 2
If naltrexone is used in combination with naloxone, monitor for symptoms of opioid withdrawal 1

Naltrexone antagonizes mu (highest affinity), kappa, and delta opioid receptors 2
It prevents patients from experiencing the euphoric effects of narcotics and alcohol 2
May reset the reward pathway through an opponent process mechanism 2
When used for obesity treatment in combination with bupropion, naltrexone antagonizes an inhibitory feedback loop that would otherwise limit bupropion's anorectic properties 4, 5