Esketamine

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Ketamine
S-ketamine-2D-skeletal.png
S-ketamine-3D-balls.png
Systematic (IUPAC) name
(S)-2-(2-chlorophenyl)-2-(methylamino)cyclohexanone
Clinical data
AHFS/Drugs.com Consumer Drug Information
Legal status ?
Identifiers
CAS number 33643-46-8 N
ATC code N01AX14
PubChem CID 182137
DrugBank DB01221
ChemSpider 158414 N
UNII 50LFG02TXD YesY
ChEBI CHEBI:6121 YesY
ChEMBL CHEMBL742 YesY
Chemical data
Formula C13H16ClNO 
Mol. mass 237.725 g/mol
 N (what is this?)  (verify)
Main article: Ketamine

Esketamine (also (S)-ketamine or S(+)-ketamine) (brand: Ketanest S) is a general anaesthetic and a dissociative. It is the S(+) enantiomer of the drug ketamine, a general anaesthetic. Esketamine is primarily an NMDA receptor antagonist. As of July 2013, it is being tested in US FDA clinical trials as an antidepressant.

Pharmacology[edit]

Esketamine is approximately twice as potent as racemic ketamine.[1] Esketamine is eliminated from the human body more quickly than R(-)-ketamine or racemic ketamine, although R(-)-ketamine slows its elimination.[2]

A number of studies have suggested that esketamine has a more medically useful pharmacological action than R(-)-ketamine or racemic ketamine. Esketamine inhibits dopamine transporters eight times more than R(-)-ketamine.[3] This increases dopamine activity in the brain. At doses causing the same intensity of effects, esketamine is generally considered to be more pleasant by patients.[4][5] Patients also generally recover mental function more quickly after being treated with pure esketamine, which may be a result of the fact that it is cleared from their system more quickly.[1][6]

Esketamine has an affinity for the PCP binding site of the NMDA receptor 3-4 times higher than that of R(-)-ketamine. Unlike R(-)-ketamine, esketamine does not bind significantly to sigma receptors. Esketamine increases glucose metabolism in frontal cortex, while R(-)-ketamine decreases glucose metabolism in the brain. This difference may be responsible for the fact that esketamine generally has a more psychedelic or hallucinatory effect while R(-)-ketamine is reported to be more relaxing.[6] However, other studies have found no difference between the isomers in the patient's level of vigilance.[4]

Potential use as an antidepressant[edit]

Johnson & Johnson is developing a nasal spray formulation of esketamine as a treatment for depression in patients that have been unresponsive to other antidepressants. As of July 2013, Phase 1 clinical trial of intranasal esketamine sponsored by the Johnson & Johnson subsidiary Janssen Pharmaceutica is underway with 58 participants in Belgium.[7] AstraZeneca (AZN) is studying lanicemine, and Naurex Inc. and Cerecor Inc. are also in the process of developing new antidepressant drugs that act similarly to ketamine.[7]

Although most studies suggest that esketamine is preferable for medical uses, a 2013 study found that the antidepressant effect of R(-)-ketamine lasted longer than those of S(+)-ketamine in mice.[8]

See also[edit]

References[edit]

  1. ^ a b Himmelseher, S.; Pfenninger, E. (2008). "Die klinische Anwendung von S-(+)-Ketamin - eine Standortbestimmung". AINS - Anästhesiologie · Intensivmedizin · Notfallmedizin · Schmerztherapie 33 (12): 764–770. doi:10.1055/s-2007-994851. PMID 9893910.  edit
  2. ^ Ihmsen, H.; Geisslinger, G.; Schüttler, J. (2001). "Stereoselective pharmacokinetics of ketamine: R(-)-ketamine inhibits the elimination of S(+)-ketamine". Clinical pharmacology and therapeutics 70 (5): 431–438. doi:10.1067/mcp.2001.119722. PMID 11719729.  edit
  3. ^ Nishimura, M.; Sato, K. (1999). "Ketamine stereoselectively inhibits rat dopamine transporter". Neuroscience letters 274 (2): 131–134. doi:10.1016/S0304-3940(99)00688-6. PMID 10553955.  edit
  4. ^ a b Doenicke, A.; Kugler, J.; Mayer, M.; Angster, R.; Hoffmann, P. (1992). "Ketamine racemate or S-(+)-ketamine and midazolam. The effect on vigilance, efficacy and subjective findings". Der Anaesthesist 41 (10): 610–618. PMID 1443509.  edit
  5. ^ Pfenninger, E.; Baier, C.; Claus, S.; Hege, G. (1994). "Psychometric changes as well as analgesic action and cardiovascular adverse effects of ketamine racemate versus s-(+)-ketamine in subanesthetic doses". Der Anaesthesist. 43 Suppl 2: S68–S75. PMID 7840417.  edit
  6. ^ a b Vollenweider, F. X.; Leenders, K. L.; Oye, I.; Hell, D.; Angst, J. (1997). "Differential psychopathology and patterns of cerebral glucose utilisation produced by (S)- and (R)-ketamine in healthy volunteers using positron emission tomography (PET)". European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology 7 (1): 25–38. doi:10.1016/S0924-977X(96)00042-9. PMID 9088882.  edit
  7. ^ a b "From Party Drug To Antidepressant: Johnson & Johnson Vs. Rivals". Seeking Alpha. July 10, 2013. 
  8. ^ Zhang, J. C.; Li, S. X.; Hashimoto, K. (2014). "R (−)-ketamine shows greater potency and longer lasting antidepressant effects than S (+)-ketamine". Pharmacology Biochemistry and Behavior 116: 137–141. doi:10.1016/j.pbb.2013.11.033. PMID 24316345.  edit