Oxymorphazone
Encyclopedia
Oxymorphazone is an opioid
analgesic
drug related to oxymorphone
. Oxymorphazone is a potent and long acting μ-opioid
agonist
which binds irreversibly to the receptor, forming a covalent bond
which prevents it from detaching once bound. This gives it an unusual pharmacological profile, and while oxymorphazone is only around half the potency of oxymorphone, with higher doses the analgesic effect becomes extremely long lasting, with a duration of up to 48 hours. However, tolerance
to analgesia develops rapidly with repeated doses, as chronically activated opioid receptors are rapidly internalised
by β-arrestin
s, similar to the results of non-covalent binding by agonists with extremely high binding affinity
such as lofentanil
.
Opioid
An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...
analgesic
Analgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
drug related to oxymorphone
Oxymorphone
Oxymorphone or 14-Hydroxydihydromorphinone is a powerful semi-synthetic opioid analgesic first developed in Germany circa 1914, patented in the USA by Endo Pharmaceuticals in 1955 and introduced to the United States market in January 1959 and other countries around the same time...
. Oxymorphazone is a potent and long acting μ-opioid
Mu Opioid receptor
The μ-opioid receptors are a class of opioid receptors with high affinity for enkephalins and beta-endorphin but low affinity for dynorphins. They are also referred to as μ opioid peptide receptors. The prototypical μ receptor agonist is the opium alkaloid morphine; μ refers to morphine...
agonist
Agonist
An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...
which binds irreversibly to the receptor, forming a covalent bond
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
which prevents it from detaching once bound. This gives it an unusual pharmacological profile, and while oxymorphazone is only around half the potency of oxymorphone, with higher doses the analgesic effect becomes extremely long lasting, with a duration of up to 48 hours. However, tolerance
Tachyphylaxis
Tachyphylaxis is a medical term describing a decrease in the response to a drug due to previous exposure to that drug. Increasing the dose of the drug may be able to restore the original response. In this context tachyphylaxis is a synonym for drug tolerance...
to analgesia develops rapidly with repeated doses, as chronically activated opioid receptors are rapidly internalised
Endocytosis
Endocytosis is a process by which cells absorb molecules by engulfing them. It is used by all cells of the body because most substances important to them are large polar molecules that cannot pass through the hydrophobic plasma or cell membrane...
by β-arrestin
Arrestin
Arrestins are a small family of proteins important for regulating signal transduction.-Function:Arrestins were first discovered as a part of a conserved two-step mechanism for regulating the activity of G protein-coupled receptors in the visual rhodopsin system by Hermann Kühn and co-workers and...
s, similar to the results of non-covalent binding by agonists with extremely high binding affinity
Dissociation constant
In chemistry, biochemistry, and pharmacology, a dissociation constant is a specific type of equilibrium constant that measures the propensity of a larger object to separate reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into...
such as lofentanil
Lofentanil
Lofentanil is one of the most potent opioid analgesics known and is an analogue of fentanyl, which was developed in 1960. It is most similar to the highly potent opioid carfentanil , only slightly more potent. Lofentanil can be described as 3-methylcarfentanil, or 3-methyl-4-carbomethoxyfentanyl...
.
See also
- ChlornaltrexamineChlornaltrexamineChlornaltrexamine is an irreversible mixed agonist-antagonist for μ-opioid receptors, which forms a covalent bond to the active site. It is 22 times more potent than morphine...
, an irreversible mixed agonist-antagonist - NaloxazoneNaloxazoneNaloxazone is an irreversible μ opioid receptor antagonist which is selective for the μ1 receptor subtype. Naloxazone produces very long lasting antagonist effects as it forms a covalent bond to the active site of the mu-opioid receptor, thus making it impossible for the molecule to unbind and...
, an irreversible μ-opioid antagonist