Buprenorphine

**Definition:** A derivative of the opioid alkaloid THEBAINE that is a more potent and longer lasting analgesic than MORPHINE. It appears to act as a partial agonist at mu and kappa opioid receptors and as an antagonist at delta receptors. The lack of delta-agonist activity has been suggested to account for the observation that buprenorphine tolerance may not develop with chronic use.

**Tree numbers:** - D03.132.577.249.150 - D03.605.497.150 - D03.633.400.686.150 - D04.615.723.795.150