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]

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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<span class="mw-page-title-main">Opioid</span> Psychoactive chemical

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

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

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

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">Dihydroetorphine</span> Opioid analgesic drug

Dihydroetorphine was developed by K. W. Bentley at McFarlan-Smith in the 1960s and is a potent opioid analgesic used mainly in China. It is a derivative of the better-known opioid etorphine, a very potent veterinary painkiller and anesthetic medication used primarily for the sedation of large animals such as elephants, giraffes, and rhinos.

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

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

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

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

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<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">Metkefamide</span> Chemical compound

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

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<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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