Partial Opioid Agonists
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Overview
Partial opioid agonists produce a limited opioid effect — enough to reduce withdrawal symptoms and cravings but with a ceiling effect that limits euphoria and respiratory depression. They are a cornerstone of medication-assisted treatment (MAT) for opioid use disorder.
How do partial opioid agonists work?
Partial opioid agonists bind to mu (μ) opioid receptors with high affinity but produce only partial receptor activation compared to full agonists like morphine or heroin. This ceiling effect means that increasing the dose beyond a certain point does not increase the opioid effect, reducing the risk of respiratory depression. Buprenorphine also acts as a kappa (κ) receptor antagonist, which may contribute to its antidepressant-like effects.
Drugs in this class
- Buprenorphine (Suboxone, Subutex, Sublocade, Buprenex, Zubsolv)