Which opioid along with Subutex makes up the two best known of the thevinol, orvinol, or bridged oripavine derivatives?
Bentley compounds The Bentley compounds are a class of semi-synthetic opioids that were first synthesized by K. W. Bentley by Diels-Alder reaction of thebaine with various dienophiles. The compounds are also known as thevinols, orvinols, or bridged oripavine derivatives, due to the characteristic 6,14-"endo"-etheno- bridge and substitution at the 7α position. Buprenorphine and etorphine are perhaps the best known of the family, which was the first series of extremely potent μ-opioid agonists, with some compounds in the series having over many thousands of times the analgesic potency of morphine.
Methylnaltrexone Methylnaltrexone (MNTX, brand name Relistor), used in form of methylnaltrexone bromide (INN, USAN, BAN), is one of the newer agents of peripherally acting μ-opioid antagonists that act to reverse some of the side effects of opioid drugs such as constipation without affecting analgesia or precipitating withdrawals. Because MNTX is a quaternary ammonium cation, it cannot cross the blood–brain barrier, and so has antagonist effects throughout the body, counteracting effects such as itching and constipation, but without affecting opioid effects in the brain such as analgesia. However, since a significant fraction (up to 60%) of opioid analgesia can be mediated by opioid receptors on peripheral sensory neurons, particularly in inflammatory conditions such as arthritis, traumatic or surgical pain, MNTX may increase pain under such circumstances.