Buprenorphine is preferred over methadone for office-based management of opioid dependence partly because of its safety profile in overdose. The pharmacodynamic property responsible for this safety advantage is:

• A Low affinity for the mu-opioid receptor, allowing easy displacement by naloxone
• B Full agonist activity limited by slow dissociation from kappa receptors
• C Pure antagonist action at the mu receptor without any agonist effect
• D Partial agonist activity at the mu receptor producing a ceiling effect on respiratory depression ✓

Explanation

Buprenorphine is a high-affinity partial agonist at the mu-opioid receptor. Its intrinsic activity is lower than that of full agonists such as methadone, so beyond a certain dose there is a ceiling on respiratory depression, the main cause of opioid overdose death. Its very high receptor affinity actually makes displacement by naloxone difficult, which is why higher naloxone doses may be needed, ruling out option A. It retains enough agonist activity to suppress withdrawal, unlike a pure antagonist.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

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Written and medically reviewed by the StethoPrep medical team.