Lofentanil

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Lofentanil
Lofentanil.svg
Lofentanil molecule ball.png
Clinical data
Other namesLofentanil; methyl (3S,4R)-1-(2-phenylethyl)-4 -(phenyl-propanoylamino)-3-methylpiperidine-4-carboxylate
ATC code
  • none
Legal status
Legal status
Identifiers
  • methyl (3S,4R)-3-methyl-1-(2-phenylethyl)-4-[phenyl(propionyl)amino]piperidine-4-carboxylate
CAS Number
PubChem CID
ChemSpider
UNII
ChEMBL
Chemical and physical data
Formula C25H32N2O3
Molar mass 408.542 g·mol−1
3D model (JSmol)
  • O=(CC)N(c1ccccc1)[C@@]2(C(OC)=O)CCN(C[C@H]2C)CCc3ccccc3
  • InChI=1S/C25H32N2O3/c1-4-23(28)27(22-13-9-6-10-14-22)25(24(29)30-3)16-18-26(19-20(25)2)17-15-21-11-7-5-8-12-21/h5-14,20H,4,15-19H2,1-3H3/t20-,25+/m1/s1 Yes check.svgY
  • Key:IMYHGORQCPYVBZ-NLFFAJNJSA-N Yes check.svgY
 X mark.svgNYes check.svgY  (what is this?)    (verify)

Lofentanil or lofentanyl 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 (4-carbomethoxyfentanyl), only slightly more potent. Lofentanil can be described as 3-methylcarfentanil, or 3-methyl-4-carbomethoxyfentanyl. While 3-methylfentanyl is considerably more potent than fentanyl itself, lofentanil is only slightly stronger than carfentanil. [1] [2] This suggests that substitution at both the 3 and 4 positions of the piperidine ring introduces steric hindrance which prevents μ-opioid affinity from increasing much further. As with other 3-substituted fentanyl derivatives such as ohmefentanyl, the stereoisomerism of lofentanil is very important, with some stereoisomers being much more potent than others.

Lofentanil is very similar to carfentanil in effects, but has a longer duration of action. [3] This makes it unsuitable for most practical applications, with carfentanil being the preferred agent for tranquilizing large animals, and short-acting derivatives such as sufentanil or remifentanil being preferred for medical use in human surgical procedures. The long duration and high lipophilicity of lofentanil has been suggested as an advantage for certain types of analgesia, [4] but the main application for lofentanil at the present time is research into opioid receptors. [5] [6] Its potency has led some to compare it to nerve agents as a chemical weapon since carfentanil's use in the Moscow hostage crisis.

Side effects of lofentanyl analogs are similar to those of fentanyl itself, which include itching, nausea, and potentially serious respiratory depression, which can be life-threatening. Fentanyl analogs have killed hundreds of people throughout Europe and the former Soviet republics since the most recent resurgence in use began in Estonia in the early 2000s, and novel derivatives continue to appear. [7] Side effects from lofentanil might be particularly problematic given its reportedly long duration of action. Another side effect which is characteristic of fentanyl and its derivatives is their tendency to rapidly induce tolerance, due to their high binding affinity triggering rapid internalization of chronically activated opiate receptors. [8] This might be expected to be a particular problem with lofentanil as it is not only one of the most potent drugs in the series, but also is longer acting than most other fentanyl analogues, meaning that development of tolerance triggered by receptor over-activation could be rapid.

In addition to acting on the μ-opioid receptor, lofentanil has also been found to act as a full agonist of the κ-opioid receptor (Ki = 8.2 nM; EC50 = 153 nM; Emax = 100%). [9]

See also

Related Research Articles

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Fentanyl is a highly potent synthetic piperidine opioid primarily used as an analgesic. It is 20 to 40 times more potent than heroin and 100 times more potent than morphine; its primary clinical utility is in pain management for cancer patients and those recovering from painful surgeries. Fentanyl is also used as a sedative. Depending on the method of delivery, fentanyl can be very fast acting and ingesting a relatively small quantity can cause overdose. Fentanyl works by activating μ-opioid receptors. Fentanyl is sold under the brand names Actiq, Duragesic and Sublimaze, among others.

<span class="mw-page-title-main">Carfentanil</span> Synthetic opioid analgesic

Carfentanil or carfentanyl, sold under the brand name Wildnil, is an extremely potent opioid analgesic used in veterinary medicine to anesthetize large animals such as elephants and rhinoceroses. It is typically administered in this context by tranquilizer dart. Carfentanil has also been used in humans to image opioid receptors. It has additionally been used as a recreational drug, typically by injection, insufflation, or inhalation. Deaths have been reported in association with carfentanil.

<span class="mw-page-title-main">Sufentanil</span> Synthetic opioid analgesic drug

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<span class="mw-page-title-main">Ohmefentanyl</span> Opioid analgesic

Ohmefentanyl is an extremely potent opioid analgesic drug which selectively binds to the μ-opioid receptor.

<span class="mw-page-title-main">3-Methylfentanyl</span> Opioid analgesic

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<span class="mw-page-title-main">Diprenorphine</span> Chemical compound

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<span class="mw-page-title-main">3-Allylfentanyl</span> Opioid analgesic

3-Allylfentanyl is an opioid analgesic that is an analogue of fentanyl.

<span class="mw-page-title-main">14-Methoxymetopon</span> Chemical compound

14-Methoxymetopon is an experimental opioid drug developed by a team led by Professor Helmut Schmidhammer at the University of Innsbruck in the mid-1990s. It is a derivative of metopon in which a methoxy group has been inserted at the 14-position. It is a highly potent analgesic drug that is around 500 times stronger than morphine when administered systemically; however, when given spinally or supraspinally, it exhibits analgesic activity up to a million fold greater than morphine. It binds strongly to the μ-opioid receptor and activates it to a greater extent than most similar opioid drugs. This produces an unusual pharmacological profile, and although 14-methoxymetopon acts as a potent μ-opioid full agonist in regard to some effects such as analgesia, a ceiling effect is seen on other effects such as constipation and respiratory depression which is believed to involve interaction with the κ-opioid receptor

<span class="mw-page-title-main">Naloxazone</span> Chemical compound

Naloxazone 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 μ-opioid receptor, thus making it impossible for the molecule to unbind and blocking the receptor permanently until the receptor is recycled by endocytosis.

<span class="mw-page-title-main">Oxymorphazone</span> Opioid analgesic

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-arrestins, similar to the results of non-covalent binding by repeated doses of agonists with extremely high binding affinity such as lofentanil.

<span class="mw-page-title-main">Arylcyclohexylamine</span> Class of chemical compounds

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<span class="mw-page-title-main">Dextrallorphan</span> Chemical compound

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<span class="mw-page-title-main">4-Phenylfentanyl</span> Opioid analgesic

4-Phenylfentanyl is an opioid analgesic that is a derivative of fentanyl. It was developed during the course of research that ultimately resulted in super-potent opioid derivatives such as carfentanil, though it is a substantially less potent analogue. 4-Phenylfentanyl is around eight times the potency of fentanyl in analgesic tests on animals, but more complex 4-heteroaryl derivatives such as substituted thiophenes and thiazoles are more potent still, as they are closer bioisosteres to the 4-carbomethoxy group of carfentanil.

<i>N</i>-Methylnorcarfentanil Opioid analgesic

N-Methylnorcarfentanil (R-32395) is an opioid analgesic drug related to the highly potent animal tranquilizer carfentanil, but several thousand times weaker, being only slightly stronger than morphine. It was first synthesised by a team of chemists at Janssen Pharmaceutica led by Paul Janssen, who were investigating the structure-activity relationships of the fentanyl family of drugs. They found that replacing the phenethyl group attached to the piperidine nitrogen of fentanyl with a smaller methyl group, made it so much weaker that it was inactive as an analgesic in animals. However the same change made to the more potent analogue carfentanil retained reasonable opioid receptor activity, reflecting the higher binding affinity produced by the 4-carbomethoxy group.

<span class="mw-page-title-main">R-30490</span> Opioid analgesic

R-30490 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 by Paul Janssen, who were investigating the structure-activity relationships of the fentanyl family of drugs. R-30490 was found to be the most selective agonist for the μ-opioid receptor out of all the fentanyl analogues tested, but it has never been introduced for medical use in humans, although the closely related drug sufentanil is widely used for analgesia and anesthesia during major surgery.

<span class="mw-page-title-main">Butyrfentanyl</span> Synthetic opioid analgesic

Butyrfentanyl or butyrylfentanyl is a potent short-acting synthetic opioid analgesic drug. It is an analog of fentanyl with around one quarter of its potency. One of the first mentions of this drug can be found in document written by The College on Problem of Drug Dependence, where it is mentioned as N-butyramide fentanyl analog. This document also states that the article describing its clinical effects was published in 1987. It is an agonist for the μ-opioid receptors.

<span class="mw-page-title-main">Thiafentanil</span> Chemical compound

Thiafentanil is a highly potent opioid analgesic that is an analog of fentanyl, and was invented in 1986. Its analgesic potency is slightly less than that of carfentanil, though with a faster onset of effects, shorter duration of action and a slightly lesser tendency to produce respiratory depression. It is used in veterinary medicine to anesthetise animals such as impala, usually in combination with other anesthetics such as ketamine, xylazine or medetomidine to reduce the prevalence of side effects such as muscle rigidity.

References

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