Carfentanil or carfentanyl, sold under the brand name Wildnil, is a very potent
opioid
Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...
analgesic
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...
which is used in
veterinary medicine
Veterinary medicine is the branch of medicine that deals with the prevention, management, diagnosis, and treatment of disease, disorder, and injury in animals. Along with this, it deals with animal rearing, husbandry, breeding, research on nutri ...
to
anesthetize
''Fear of a Blank Planet'' is the ninth studio album by British progressive rock band Porcupine Tree and their best selling before 2009's '' The Incident''. It was released on 16 April 2007 in the UK and the rest of Europe by Roadrunner, 2 ...
large animals such as
elephant
Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantida ...
s and
rhinoceros
A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct specie ...
es.
It is typically administered in this context by
tranquilizer dart.
Carfentanil has also been used in humans for
imaging
Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image).
Imaging technology is the application of materials and methods to create, preserve, or duplicate images.
...
of
opioid receptor
Opioid receptors are a group of inhibitory G protein-coupled receptors with opioids as ligands. The endogenous opioids are dynorphins, enkephalins, endorphins, endomorphins and nociceptin. The opioid receptors are ~40% identical to somatostatin ...
s.
It has additionally been used as a
recreational drug
Recreational drug use indicates the use of one or more psychoactive drugs to induce an altered state of consciousness either for pleasure or for some other casual purpose or pastime by modifying the perceptions and emotions of the user. When a ...
, typically by
injection,
insufflation
In religious and magical practice, insufflation and exsufflation are ritual acts of blowing, breathing, hissing, or puffing that signify variously expulsion or renunciation of evil or of the devil (the Evil One), or infilling or blessing with go ...
, or
inhalation
Inhalation (or Inspiration) happens when air or other gases enter the lungs.
Inhalation of air
Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic (though there are exceptions ...
.
Deaths have been reported in association with carfentanil.
Effects and
side effect
In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...
s of carfentanil in humans are similar to those of other opioids and include
euphoria
Euphoria ( ) is the experience (or affect) of pleasure or excitement and intense feelings of well-being and happiness. Certain natural rewards and social activities, such as aerobic exercise, laughter, listening to or making music and d ...
,
relaxation,
pain relief
Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professional ...
,
pupil constriction,
drowsiness
Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep ...
,
sedation
Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of drugs which can be used for sedation include isoflurane, diethyl ether, ...
,
slowed heart rate,
low blood pressure
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the di ...
,
lowered body temperature,
loss of consciousness
Loss may refer to:
Arts, entertainment, and media Music
* ''Loss'' (Bass Communion album) (2006)
* ''Loss'' (Mull Historical Society album) (2001)
*"Loss", a song by God Is an Astronaut from their self-titled album (2008)
* Losses "(Lil Tjay son ...
, and
suppression of breathing.
The effects of carfentanil, including
overdose
A drug overdose (overdose or OD) is the ingestion or application of a drug or other substance in quantities much greater than are recommended. , can be reversed by the
opioid antagonist
An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors.
Naloxone and naltrexone are commonly used opioid antagonist drugs which are competitive antagonists that bind to the ...
s
naloxone
Naloxone, sold under the brand names Narcan (4 mg) and Kloxxado (8 mg) among others, is a medication used to reverse or reduce the effects of opioids. It is commonly used to counter decreased breathing in opioid overdose. Effects begin withi ...
and
naltrexone
Naltrexone, sold under the brand name Revia among others, is a medication primarily used to manage alcohol or opioid use disorder by reducing cravings and feelings of euphoria associated with substance use disorder. It has also been foun ...
, though higher or multiple doses than usual may be necessary compared to other opioids.
Carfentanil is a
structural analogue of the
synthetic Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to:
Science
* Synthetic chemical or compound, produced by the process of chemical synthesis
* Synthetic ...
opioid analgesic
fentanyl
Fentanyl, also spelled fentanil, is a very potent synthetic opioid used as a pain medication. Together with other drugs, fentanyl is used for anesthesia. It is also used illicitly as a recreational drug, sometimes mixed with heroin, cocain ...
. It acts as an
ultrapotent and highly
selective agonist
An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ag ...
of the
μ-opioid receptor
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 ...
.
Carfentanil was first synthesized in 1974 by a team of chemists at
Janssen Pharmaceutica
Janssen Pharmaceuticals is a pharmaceutical company headquartered in Beerse, Belgium, and wholly-owned by Johnson & Johnson. It was founded in 1953 by Paul Janssen.
In 1961, Janssen Pharmaceuticals was purchased by New Jersey-based American ...
which included
Paul Janssen
Paul Adriaan Jan, Baron Janssen (12 September 1926 - 11 November 2003) was a Belgian physician. He was the founder of Janssen Pharmaceutica, a pharmaceutical company with over 20,000 employees which is now a subsidiary of Johnson & Johnson.
Ea ...
.
It was introduced into veterinary medicine in 1986.
Carfentanil is legally controlled in most jurisdictions.
Uses
Veterinary use
Chosen for its high
therapeutic index
The therapeutic index (TI; also referred to as therapeutic ratio) is a quantitative measurement of the relative safety of a drug. It is a comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes ...
, carfentanil was first sold in 1986 under the brand name "Wildnil" for use in combination with an
α2-receptor agonist as a
tranquilizing agent for large mammals like hippos, rhinos, and elephants.
Commercial production of Wildnil ceased in 2003; the drug is now available only in
compounded form.
Clinical use
Carfentanil has been used at doses of less than 7 μg as a
radiotracer
A radioactive tracer, radiotracer, or radioactive label is a chemical compound in which one or more atoms have been replaced by a radionuclide so by virtue of its radioactive decay it can be used to explore the mechanism of chemical reactions by tr ...
for
positron emission tomography
Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, ...
imaging
Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image).
Imaging technology is the application of materials and methods to create, preserve, or duplicate images.
...
of the
μ-opioid receptor
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 ...
in the brain in humans.
Pharmacology
Pharmacodynamics
Carfentanil acts as a highly
selective agonist
An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ag ...
of the
μ-opioid receptor
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 ...
.
It showed
affinity values (K
i) of 0.051 nM for the μ-opioid receptor, 4.7 nM for the
δ-opioid receptor
The δ-opioid receptor, also known as delta opioid receptor or simply delta receptor, abbreviated DOR or DOP, is an inhibitory 7-transmembrane G-protein coupled receptor coupled to the G protein Gi/G0 and has enkephalins as its endogenous lig ...
, and 13 nM for the
κ-opioid receptor
The κ-opioid receptor or kappa opioid receptor, abbreviated KOR or KOP, is a G protein-coupled receptor that in humans is encoded by the ''OPRK1'' gene. The KOR is coupled to the G protein Gi/G0 and is one of four related receptors that bind ...
in rat brain.
Thus, carfentanil displayed 90- and 250-fold selectivity for the μ-opioid receptor over the δ-opioid receptor and the κ-opioid receptor, respectively.
With human proteins, the affinities were 0.024 nM for the μ-opioid receptor, 3.3 nM for the δ-opioid receptor, and 43 nM for the κ-opioid receptor, demonstrating 140- and 1,800-fold selectivity for the μ-opioid receptor over the δ- and κ-opioid receptors, respectively.
Carfentanil appears to have higher affinity for the
μ1-opioid receptor over the
μ2-opioid receptor.
Carfentanil has approximately 10,000 times the
analgesic
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...
potency
Potency may refer to:
* Potency (pharmacology), a measure of the activity of a drug in a biological system
* Virility
* Cell potency, a measure of the differentiation potential of stem cells
* In homeopathic dilutions, potency is a measure of how ...
of
morphine
Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies ('' Papaver somniferum''). It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. T ...
, 4,000 times the potency of
heroin
Heroin, also known as diacetylmorphine and diamorphine among other names, is a potent opioid mainly used as a recreational drug for its euphoric effects. Medical grade diamorphine is used as a pure hydrochloride salt. Various white and bro ...
, and 20 to 100 times the potency of fentanyl in animal studies.
The effects of carfentanil are reversed by
μ-opioid receptor antagonists like
naloxone
Naloxone, sold under the brand names Narcan (4 mg) and Kloxxado (8 mg) among others, is a medication used to reverse or reduce the effects of opioids. It is commonly used to counter decreased breathing in opioid overdose. Effects begin withi ...
and
naltrexone
Naltrexone, sold under the brand name Revia among others, is a medication primarily used to manage alcohol or opioid use disorder by reducing cravings and feelings of euphoria associated with substance use disorder. It has also been foun ...
, though higher than normal doses of these agents may be necessary in humans due to the extremely high potency of carfentanil.
Pharmacokinetics
A
lipophilic
Lipophilicity (from Greek λίπος "fat" and φίλος "friendly"), refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such non-polar solvents are themselves lipo ...
chemical that can easily cross the
blood–brain barrier
The blood–brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of the central nervous system where ne ...
, carfentanil has a very rapid
onset of action
Onset of action is the duration of time it takes for a drug's effects to come to prominence upon administration. With oral administration, it typically ranges anywhere from 20 minutes to over an hour, depending on the drug in question. Other meth ...
and is longer acting than fentanyl.
Its
elimination half-life
Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the b ...
in humans was 42 to 51 minutes following an
intravenous bolus
Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...
at an average dose of 1.34 μg (19 ng/kg).
However, in a case study of recreational exposure, the half-lives of carfentanil and its
metabolite
In biochemistry, a metabolite is an intermediate or end product of metabolism.
The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, ...
norcarfentanil were estimated to be 5.7 hours and 11.8 hours, respectively.
Chemistry
![Fentanyl numbering](https://upload.wikimedia.org/wikipedia/commons/a/aa/Fentanyl_numbering.svg)
Carfentanil is an
analogue of
fentanyl
Fentanyl, also spelled fentanil, is a very potent synthetic opioid used as a pain medication. Together with other drugs, fentanyl is used for anesthesia. It is also used illicitly as a recreational drug, sometimes mixed with heroin, cocain ...
and is also known as (4-methoxycarbonyl)fentanyl. Related analogues of fentanyl include
4-phenylfentanyl,
lofentanil (3-methylcarfentanyl),
N-methylcarfentanil,
R-30490
R-30490 (also known as 4-methoxymethylfentanyl) is an opioid analgesic related to the highly potent animal tranquilizer carfentanil, and with only slightly lower potency. It was first synthesised by a team of chemists at Janssen Pharmaceutica led ...
(4-methoxymethylfentanyl),
sufentanil, and
thiafentanil.
History
Increase in illicit use
![Fentanyl](https://upload.wikimedia.org/wikipedia/commons/5/53/Fentanyl._2_mg._A_lethal_dose_in_most_people.jpg)
Over three hundred cases of overdose related to fentanyl and fentanyl analogues were reported between August and November 2016 in several of the United States, including
Ohio
Ohio () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Of the List of states and territories of the United States, fifty U.S. states, it is the List of U.S. states and territories by area, 34th-l ...
,
West Virginia
West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the ...
,
Indiana
Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th ...
,
Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...
and
Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...
.
In 2017, a
Milwaukee
Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee i ...
,
Wisconsin
Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...
, man died from a carfentanil overdose, likely taken unknowingly with another illegal drug such as
heroin
Heroin, also known as diacetylmorphine and diamorphine among other names, is a potent opioid mainly used as a recreational drug for its euphoric effects. Medical grade diamorphine is used as a pure hydrochloride salt. Various white and bro ...
or
cocaine
Cocaine (from , from , ultimately from Quechuan languages, Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly recreational drug use, used recreationally for its euphoria, euphoric effects. It is primarily obtained from t ...
. Carfentanil is most often taken with
heroin
Heroin, also known as diacetylmorphine and diamorphine among other names, is a potent opioid mainly used as a recreational drug for its euphoric effects. Medical grade diamorphine is used as a pure hydrochloride salt. Various white and bro ...
or by users who believe they are taking heroin. Carfentanil is added to or sold as heroin because it is less expensive, easier to obtain, and easier to manufacture than heroin.
Health professionals are concerned about the potential escalation of public health consequences of its recreational use.
Importation from China
Authorities in Latvia and Lithuania reported seizing carfentanil as an illicit drug in the early 2000s.
Around 2016, the United States and Canada reported a dramatic increase in shipment of carfentanil and other strong
opioid
Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...
drugs to customers in North America from Chinese chemical supply firms. In June 2016, the
Royal Canadian Mounted Police
The Royal Canadian Mounted Police (RCMP; french: Gendarmerie royale du Canada; french: GRC, label=none), commonly known in English as the Mounties (and colloquially in French as ) is the federal police, federal and national police service of ...
seized one kilogram of carfentanil shipped from China in a box labeled "printer accessories". According to the Canada Border Services Agency, the shipment contained 50 million lethal doses of the drug, more than enough to annihilate the entire population of the country, in containers labeled as
toner cartridge
A toner cartridge, also called laser toner, is the consumable component of a laser printer. Toner cartridges contain toner powder, a fine, dry mixture of plastic particles, carbon, and black or other coloring agents that make the actual image o ...
s for
HP LaserJet
LaserJet as a brand name identifies the line of laser printers marketed by the American computer company Hewlett-Packard (HP). The HP LaserJet was the first popular desktop laser printer. Canon supplies both mechanisms and cartridges for most HP ...
printers.
Carfentanil was not a controlled substance in China until 1 March 2017, and until then was manufactured legally and sold openly over the Internet, being actively marketed by several Chinese chemical companies.
Moscow theater hostage crisis
In 2012, a team of researchers at the British chemical and biological defence laboratories at
Porton Down
Porton Down is a science park in Wiltshire, England, just northeast of the village of Porton, near Salisbury. It is home to two British government facilities: a site of the Ministry of Defence's Defence Science and Technology Laboratory (Dstl ...
found carfentanil and
remifentanil
Remifentanil is a potent, short-acting synthetic opioid analgesic drug. It is given to patients during surgery to relieve pain and as an adjunct to an anaesthetic. Remifentanil is used for sedation as well as combined with other medications fo ...
in clothing from two British survivors of the 2002
Moscow theater hostage crisis
The Moscow theater hostage crisis (also known as the 2002 Nord-Ost siege) was the seizure of the crowded Dubrovka Theater by Chechen terrorists on 23 October 2002, which involved 850 hostages and ended with Russian security services killing o ...
and in the urine from a third survivor. The team concluded that the Russian military had used an
aerosol mist of carfentanil and remifentanil to subdue
Chechen hostage takers. Researchers had previously surmised from the available evidence that the Moscow
emergency services
Emergency services and rescue services are organizations that ensure public safety and health by addressing and resolving different emergencies. Some of these agencies exist solely for addressing certain types of emergencies, while others deal wit ...
had not been informed of the use of the agent, despite being instructed to bring
opioid antagonist
An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors.
Naloxone and naltrexone are commonly used opioid antagonist drugs which are competitive antagonists that bind to the ...
s to the scene. Unaware that hundreds of patients had been exposed to high doses of strong opioids, the emergency workers failed to bring sufficient quantities of
naloxone
Naloxone, sold under the brand names Narcan (4 mg) and Kloxxado (8 mg) among others, is a medication used to reverse or reduce the effects of opioids. It is commonly used to counter decreased breathing in opioid overdose. Effects begin withi ...
and
naltrexone
Naltrexone, sold under the brand name Revia among others, is a medication primarily used to manage alcohol or opioid use disorder by reducing cravings and feelings of euphoria associated with substance use disorder. It has also been foun ...
to counteract the effects of carfentanil and remifentanil. As a result, one hundred twenty-five people exposed to the aerosol are confirmed to have died from
respiratory failure
Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide, or both cannot be kept at normal levels. A drop in the oxygen carried in the blood is known as hypoxemia; a rise ...
during the incident.
Potential as a chemical weapon
The toxicity of carfentanil in humans and its ready commercial availability has raised concerns over its potential use as a chemical
weapon of mass destruction
A weapon of mass destruction (WMD) is a chemical, biological, radiological, nuclear, or any other weapon that can kill and bring significant harm to numerous individuals or cause great damage to artificial structures (e.g., buildings), natura ...
by
rogue nation
"Rogue state" (or sometimes "outlaw state") is a term applied by some international theorists to states that they consider threatening to the world's peace. These states meet certain criteria, such as being ruled by Authoritarianism, authorita ...
s and
terrorist group
A number of national governments and two international organizations have created lists of organizations that they designate as terrorist. The following list of designated terrorist groups lists groups designated as terrorist by current and fo ...
s. The toxicity of carfentanil has been compared to that of
nerve gas
Nerve agents, sometimes also called nerve gases, are a class of organic chemicals that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by the blocking of acetylcholinesterase (AChE), an enzyme that ...
.
Society and culture
Legal status
China
Carfentanil has been controlled in China since 1 March 2017.
The
trade war
A trade war is an economic conflict often resulting from extreme protectionism in which states raise or create tariffs or other trade barriers against each other in response to trade barriers created by the other party. If tariffs are the exclus ...
between China and the United States has included controversy over the effectiveness of this control.
Germany
Carfentanil and it’s
stereoisomers
In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in ...
and
salts
In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively cha ...
are controlled by the
Betäubungsmittelgesetz
The Betäubungsmittelgesetz (BtMG), generally meaning Narcotics Law, is the controlled substances law of Germany. In common with the Misuse of Drugs Act of 1971 of the United Kingdom and Controlled Substances Acts of the US and Canada, it is a con ...
as a
anlage I
Anlage may refer to:
* Allele, a specific version of a gene, as used by Gregor Mendel
* Anlage Süd, a headquarters facility of the German Third Reich in Strzyżów, Poland
* Primordium, the initial clustering of embryonic cells from which a body ...
substance and can only be used with the special permission of the authorities
United States
Carfentanil is classified as
Schedule II under the
Controlled Substances Act
The Controlled Substances Act (CSA) is the statute establishing federal government of the United States, federal drug policy of the United States, U.S. drug policy under which the manufacture, importation, possession, use, and distribution of ...
in the United States with a
DEA
The Drug Enforcement Administration (DEA; ) is a United States federal law enforcement agency under the U.S. Department of Justice tasked with combating drug trafficking and distribution within the U.S. It is the lead agency for domestic en ...
ACSCN Administrative Controlled Substances Code Number (ACSCN) is a number assigned to drugs listed on the schedules created by the US Controlled Substances Act (CSA). The ACSCN is defined in 21 CFR § 1308.03(a).
Each chemical/drug on one of the schedu ...
of 9743 and a 2016 annual aggregate manufacturing quota of 19 grams (less than 0.7 oz.).
United Kingdom
Carfentanil has been specifically controlled as a Class A drug since 1986.
See also
*
Opioid potency comparison
References
{{Opioid receptor modulators
1974 introductions
Anilides
Belgian inventions
Carboxylate esters
Fentanyl
General anesthetics
Janssen Pharmaceutica
Methyl esters
Mu-opioid receptor agonists
Piperidines
Propionamides
Synthetic opioids
Veterinary drugs
Incapacitating agents