Diprenorphine
Encyclopedia
Diprenorphine is an opioid antagonist
used to reverse the effects of the super-potent opioid analgesics such as etorphine
and carfentanil
that are used for tranquilizing large animals in veterinary medicine.
Diprenorphine is the strongest opiate antagonist that is commercially available (some 100 times more potent as an antagonist than nalorphine
), and is used for reversing the effects of very strong opioids for which the binding affinity is so high that naloxone
does not effectively or reliably reverse the narcotic effects. These super-potent opioids are not used in humans because the dose for a human is so small that it would be difficult to measure properly, so there is an excessive risk of overdose leading to fatal respiratory depression. However conventional opioid derivatives are not strong enough to rapidly tranquilize large animals such as elephants and rhinos, so drugs such as etorphine or carfentanil are available for this purpose.
Diprenorphine is considered the specific antagonist for etorphine and carfentanil, and is normally used to remobilise animals once veterinary procedures have been completed,. Because diprenorphine also has some agonistic properties of its own, it should not be used on humans in the event that they are accidentally exposed to etorphine or carfentanil. Naloxone or naltrexone are the preferred human antagonists.
In theory, diprenorphine could also be used as an antidote for treating overdose of certain opioid derivatives which are used in humans, such as buprenorphine
, for which the binding affinity is so high that naloxone does not reliably reverse the narcotic effects. However, diprenorphine is not generally available in hospitals; instead a vial of diprenorphine is supplied with etorphine or carfentanil specifically for reversing the effects of these drugs, so use of diprenorphine for treating e.g. a buprenorphine overdose is not carried out in practice, although it would work in theory.
Opioid antagonist
An opioid antagonist is a receptor antagonist that acts on opioid receptors.Naloxone and naltrexone are commonly used opioid antagonist drugs which are competitive antagonists that bind to the opioid receptors with higher affinity than agonists but do not activate the receptors...
used to reverse the effects of the super-potent opioid analgesics such as etorphine
Etorphine
Etorphine is a semi-synthetic opioid possessing an analgesic potency approximately 200 times that of morphine. It was first prepared in 1960 from oripavine, which does not generally occur in opium poppy extract but rather in "poppy straw" and in related plants, Papaver orientale and Papaver...
and carfentanil
Carfentanil
Carfentanil or carfentanyl is an analogue of the popular synthetic opioid analgesic fentanyl, and is one of the most potent opioids known . Carfentanil was first synthesized in 1974 by a team of chemists at Janssen Pharmaceutica which included Paul Janssen...
that are used for tranquilizing large animals in veterinary medicine.
Diprenorphine is the strongest opiate antagonist that is commercially available (some 100 times more potent as an antagonist than nalorphine
Nalorphine
Nalorphine trade names Lethidrone and Nalline. Nalorphine acts at two opioid receptors, at the mu receptor it has antagonistic effects and at the kappa receptors it exerts agonistic characteristics. It is used to reverse opioid overdose and in a challenge test to determine opioid dependence....
), and is used for reversing the effects of very strong opioids for which the binding affinity is so high that naloxone
Naloxone
Naloxone is an opioid antagonist drug developed by Sankyo in the 1960s. Naloxone is a drug used to counter the effects of opiate overdose, for example heroin or morphine overdose. Naloxone is specifically used to counteract life-threatening depression of the central nervous system and respiratory...
does not effectively or reliably reverse the narcotic effects. These super-potent opioids are not used in humans because the dose for a human is so small that it would be difficult to measure properly, so there is an excessive risk of overdose leading to fatal respiratory depression. However conventional opioid derivatives are not strong enough to rapidly tranquilize large animals such as elephants and rhinos, so drugs such as etorphine or carfentanil are available for this purpose.
Diprenorphine is considered the specific antagonist for etorphine and carfentanil, and is normally used to remobilise animals once veterinary procedures have been completed,. Because diprenorphine also has some agonistic properties of its own, it should not be used on humans in the event that they are accidentally exposed to etorphine or carfentanil. Naloxone or naltrexone are the preferred human antagonists.
In theory, diprenorphine could also be used as an antidote for treating overdose of certain opioid derivatives which are used in humans, such as buprenorphine
Buprenorphine
Buprenorphine is a semi-synthetic opioid that is used...
, for which the binding affinity is so high that naloxone does not reliably reverse the narcotic effects. However, diprenorphine is not generally available in hospitals; instead a vial of diprenorphine is supplied with etorphine or carfentanil specifically for reversing the effects of these drugs, so use of diprenorphine for treating e.g. a buprenorphine overdose is not carried out in practice, although it would work in theory.