Hydrocodone, also known as dihydrocodeinone, is a semi-synthetic opioid used to treat pain and as a cough suppressant. It is taken by mouth. Typically it is dispensed as the combination acetaminophen/hydrocodone or ibuprofen/hydrocodone for pain severe enough to require an opioid and in combination with homatropine methylbromide to relieve cough. It is also available by itself in a long-acting form sold under the brand name Zohydro ER, among others, to treat severe pain of a prolonged duration. Hydrocodone is a controlled drug: in the United States a Schedule II Controlled Substance.
Morphine, formerly also called morphia, is an opiate that is found naturally in opium, a dark brown resin produced by drying the latex of opium poppies. It is mainly used as an analgesic. There are numerous methods used to administer morphine: oral; sublingual; via inhalation; injection into a muscle, injection under the skin, or injection into the spinal cord area; transdermal; or via rectal suppository. It acts directly on the central nervous system (CNS) to induce analgesia and alter perception and emotional response to pain. Physical and psychological dependence and tolerance may develop with repeated administration. It can be taken for both acute pain and chronic pain and is frequently used for pain from myocardial infarction, kidney stones, and during labor. Its maximum effect is reached after about 20 minutes when administered intravenously and 60 minutes when administered by mouth, while the duration of its effect is 3–7 hours. Long-acting formulations of morphine are sold under the brand names MS Contin and Kadian, among others. Generic long-acting formulations are also available.
Opioids are a class of drugs that derive from, or mimic, natural substances found in the opium poppy plant. Opioids work in the brain to produce a variety of effects, including pain relief. As a class of substances, they act on opioid receptors to produce morphine-like effects.
Nalbuphine, sold under the brand names Nubain among others, is an opioid analgesic which is used in the treatment of pain. It is given by injection into a vein, muscle, or fat.
An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors.
Morphinan is the prototype chemical structure of a large chemical class of psychoactive drugs, consisting of opiate analgesics, cough suppressants, and dissociative hallucinogens, among others. Typical examples include compounds such as morphine, codeine, and dextromethorphan (DXM). Despite related molecular structures, the pharmacological profiles and mechanisms of action between the various types of morphinan substances can vary substantially. They tend to function either as μ-opioid receptor agonists (analgesics), or NMDA receptor antagonists (dissociatives).
The μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(mu)-opioid peptide (MOP) receptors. The prototypical μ-opioid receptor agonist is morphine, the primary psychoactive alkaloid in opium and for which the receptor was named, with mu being the first letter of Morpheus, the compound's namesake in the original Greek. It is an inhibitory G-protein coupled receptor that activates the Gi alpha subunit, inhibiting adenylate cyclase activity, lowering cAMP levels.
Desmetramadol, also known as O-desmethyltramadol (O-DSMT), is an opioid analgesic and the main active metabolite of tramadol. Tramadol is demethylated by the liver enzyme CYP2D6 to desmetramadol in the same way as codeine, and so similarly to the variation in effects seen with codeine, individuals who have a less active form of CYP2D6 will tend to have reduced analgesic effects from tramadol. Because desmetramadol itself does not need to be metabolized to induce an analgesic effect, it can be used in individuals with low CYP2D6 activity unlike tramadol.
Nalorphine, also known as N-allylnormorphine, is a mixed opioid agonist–antagonist with opioid antagonist and analgesic properties. It was introduced in 1954 and was used as an antidote to reverse opioid overdose and in a challenge test to determine opioid dependence.
Dezocine, sold under the brand name Dalgan, is an atypical opioid analgesic which is used in the treatment of pain. It is used by intravenous infusion and intramuscular injection.
Ciramadol (WY-15,705) is an opioid analgesic that was developed in the late 1970s and is related to phencyclidine, tramadol, tapentadol and venlafaxine. It is a mixed agonist-antagonist for the μ-opioid receptor with relatively low abuse potential and a ceiling on respiratory depression which makes it a relatively safe drug. It has a slightly higher potency and effectiveness as an analgesic than codeine, but is weaker than morphine. Other side effects include sedation and nausea but these are generally less severe than with other similar drugs.
Propiram is a partial μ-opioid receptor agonist and weak μ antagonist analgesic from the ampromide family of drugs related to other drugs such as phenampromide and diampromide. It was invented in 1963 in the United Kingdom by Bayer but was not widely marketed, although it saw some limited clinical use, especially in dentistry. Propiram reached Phase III clinical trials in the United States and Canada.
Metofoline (INN), also known as methofoline (USAN), is an opioid analgesic drug discovered in the 1950s by a team of Swiss researchers at Hoffmann-La Roche.
Xorphanol (INN), also known as xorphanol mesylate (USAN), is an opioid analgesic of the morphinan family that was never marketed.
In pharmacology the term agonist-antagonist or mixed agonist/antagonist is used to refer to a drug which under some conditions behaves as an agonist while under other conditions, behaves as an antagonist.
β-Chlornaltrexamine (β-CNA) is a non-selective irreversible antagonist of the μ-opioid receptor (MOR), the δ-opioid receptor (DOR), and the κ-opioid receptor (KOR), which forms a covalent bond to the binding sites of these receptors and has ultra-long-lasting opioid antagonist effects. Although it is predominantly antagonistic, β-CNA also shows some irreversible mixed agonist–antagonist activity at the MOR and KOR and some associated analgesic effects. Its alkylating group is a bis(chloroalkyl)amino-residue similar to that of the nitrogen mustards.
An opiate is an alkaloid substance derived from opium. It differs from the similar term opioid in that the latter is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain. Opiates are alkaloid compounds naturally found in the opium poppy plant Papaver somniferum. The psychoactive compounds found in the opium plant include morphine, codeine, and thebaine. Opiates have long been used for a variety of medical conditions, with evidence of opiate trade and use for pain relief as early as the eighth century AD. Most opiates are considered drugs with moderate to high abuse potential and are listed on various "Substance-Control Schedules" under the Uniform Controlled Substances Act of the United States of America.
Proxorphan (INN), also known as proxorphan tartate (USAN), is an opioid analgesic and antitussive drug of the morphinan family that was never marketed. It acts preferentially as a κ-opioid receptor partial agonist and to a lesser extent as a μ-opioid receptor partial agonist.
Benzhydrocodone (INN) is an opioid prodrug of the morphinan class. Its chemical structure consists of hydrocodone coupled with benzoic acid. Benzhydrocodone itself is inactive and acts as a prodrug to hydrocodone upon cleavage of the benzoate portion of the molecule.
β-Funaltrexamine (β-FNA) is an irreversible opioid antagonist that was used to create the first crystal structure of the μ-opioid receptor (MOR). It is selective for antagonism of the MOR over the δ-opioid receptor (DOR) and κ-opioid receptor (KOR). Chemically, it is a naltrexone derivative with a methyl-fumaramide group in the 6-position. In addition to its MOR irreversible antagonism, β-FNA is a reversible agonist of the κ-opioid receptor (KOR) and produces KOR-mediated analgesic effects in animals. This has limited its usefulness and contributed to the development of methocinnamox as a more selective functionally irreversible antagonist of the MOR with no significant opioid agonistic actions.
