Which MAT medication is a partial opioid agonist?

• A. Methadone
• B. Buprenorphine
• C. Naloxone
• D. Naltrexone

Answer: (B)

Partial opioid agonist activity means the medication activates mu-opioid receptors but only to a limited extent, providing withdrawal relief and cravings reduction with a built-in ceiling on effects like euphoria and respiratory depression. Buprenorphine fits this profile: it binds strongly to mu receptors with high affinity and activates them, but only partially, so patients gain enough relief without the full opioid effect. That ceiling lowers the risk of overdose and makes it safer for long-term maintenance in MAT. It’s also commonly prescribed with naloxone to discourage misuse. In contrast, methadone is a full opioid agonist and can produce the full opioid effect and greater overdose risk, while naloxone and naltrexone are antagonists that block opioid effects rather than activating receptors.