Buprenorphine is a morphinane alkaloid that is 7,8-dihydromorphine 6-O-methyl ether in which positions 6 and 14 are joined by a -CH2CH2- bridge, one of the hydrogens of the N-methyl group is substituted by cyclopropyl, and a hydrogen at position 7 is substituted by a 2-hydroxy-3,3-dimethylbutan-2-yl group. It is highly effective for the treatment of opioid use disorder and is also increasingly being used in the treatment of chronic pain. It has a role as an opioid analgesic, a mu-opioid receptor agonist, a delta-opioid receptor antagonist and a kappa-opioid receptor antagonist.