What is Samidorphan?
Samidorphan is a µ-opioid receptor antagonist that also has partial agonist activity at κ- and δ-opioid receptors in vitro. It has µ-opioid antagonist effects that last up to 24 hours and hasgreater affinity for the µ-opioid receptor than both naltrexone and buprenorphine. In May 2021, olanzapine/samidorphan was approved by the United States Food and Drug Administration after samidorphan was shown to decrease olanzapine-associated weight gain. It is contraindicated in opioid-dependent patients due to its ability to precipitate withdrawal.
Nicholus M. Warstadt, Zachary P. Schmitz & Samara E. Soghoian (2022) Olanzapine/samidorphan precipitated opioid withdrawal in a patient taking transdermal fentanyl, Clinical Toxicology, 60:7, 891-892, DOI: 10.1080/15563650.2022.2049286