Buprenorphine is used for opioid dependence maintenance therapy and chronic pain. Its pharmacological profile—partial mu agonist and kappa antagonist—confers which advantage over full mu agonists like methadone?

• A Ceiling effect on respiratory depression, reducing fatal overdose risk; high receptor affinity means other opioids cannot easily displace it, reducing abuse potential ✓
• B Complete absence of physical dependence and no withdrawal syndrome on abrupt discontinuation
• C It is more effective than methadone for pain because partial agonism produces stronger analgesia at receptor saturation
• D No sedation or euphoria, making it completely free of misuse potential

Explanation

Buprenorphine's partial mu agonism produces a ceiling (plateau) effect: beyond a certain dose, further increases do not increase respiratory depression, markedly reducing the risk of fatal overdose compared with full agonists such as methadone or heroin. Its extremely high mu-receptor affinity (Kd ~1 nM) and slow receptor dissociation (long half-life ~24–72 hours) mean that if a patient on buprenorphine uses additional opioids, displacement from receptors is difficult, limiting abuse potential. Patients still develop physical dependence and will experience withdrawal on abrupt discontinuation.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.