Buprenorphine, used in opioid dependence treatment, has a lower risk of respiratory depression than full agonists at high doses due to:

• A Ceiling effect — partial agonism at μ-receptors limits maximal respiratory depression even at high doses ✓
• B κ-receptor antagonism that counteracts respiratory depression caused by μ-agonism
• C Very short half-life preventing accumulation to toxic levels
• D Active metabolite that antagonises μ-receptors in the respiratory centre

Explanation

Buprenorphine is a partial agonist at μ-opioid receptors with very high receptor affinity but submaximal intrinsic efficacy. At μ-receptors in the respiratory centres, its partial agonism produces a ceiling effect — increasing doses beyond a certain point do not produce proportionally greater respiratory depression, unlike full agonists (morphine, fentanyl). Combined with its κ-antagonism (which reduces dysphoria) and long half-life, it makes an effective and safer maintenance agent.

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

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Written and medically reviewed by the StethoPrep medical team.