(1S,2S,6R,14R,16R)-5-(cyclopropylmethyl)-16-(2-hydroxy-3,3-dimethylbutan-2-yl)-15-methoxy-13-oxa-5-azahexacyclo[13.2.2.12,8.01,6.02,14.012,20]icosa-8(20),9,11-trien-11-ol;hydrochloride
Buprenorphine Hydrochloride is the hydrochloride salt form of buprenorphine, a synthetic phenanthrene with narcotic analgesic activity. Buprenorphine hydrochloride is a partial agonist at the mu-opioid receptor and an antagonist at the kapa-opioid receptor in the central nervous system. However, under the conditions of recommended use it behaves as a classic mu-opioid agonist, mimicking the actions of endogenous peptides at CNS opioid receptors. The agonist action results in a raised pain threshold and increased tolerance to pain.  However, it also causes sedation, physical dependence, and respiratory depressant effects and decreases heart rate and blood pressure.