DOI: 10.12809/hkmj177089
© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
LETTER TO THE EDITOR
2-oxo-PCE: ketamine analogue on the streets
YK Chong, FHKCPath, FHKAM (Pathology)1,2;
Magdalene HY Tang, PhD1; CL Chan, MSc2; YK Li,
FHKCEM, FHKAM (Emergency Medicine)3; CK Ching, FRCPA, FHKAM
(Pathology)1,2; Tony WL Mak, FHKCPath, FHKAM (Pathology)1,2
1 Hospital Authority Toxicology
Reference Laboratory, Princess Margaret Hospital, Laichikok, Hong Kong
2 Chemical Pathology Laboratory,
Department of Pathology, Princess Margaret Hospital, Laichikok, Hong Kong
3 Accident and Emergency Department,
Princess Margaret Hospital, Laichikok, Hong Kong
Corresponding author: Dr Tong WL Mak (makwl@ha.org.hk)
Full
paper in PDF
To the Editor—New psychoactive substances
are recently emerged drugs that are chemically or pharmacologically
similar to conventional drugs of abuse. Our laboratory has repeatedly
identified new psychoactive substances in Hong Kong.1 2 3
We report the identification of 2-oxo-PCE
[2-phenyl-2-(ethylamino)-cyclohexanone, also known as
deschloro-N-ethyl-ketamine or deschloro-N-ethyl-norketamine] in urine
samples of multiple unrelated patients in October 2017 with suspected
ketamine abuse or related poisoning features. An unidentified substance
was detected in these samples by general toxicology screening using
high-performance liquid chromatography-diode array detection; further
investigations at our laboratory confirmed the unidentified substance as
2-oxo-PCE by liquid chromatography-tandem mass spectrometry. This compound
is not routinely covered by general toxicology screening and in our
experience does not cross-react with at least one bedside ketamine
immunoassay (ABON; Abon Biopharm [Hangzhou] Co Ltd, Hangzhou, PRC).
The drug, 2-oxo-PCE, is a new psychoactive
substance in the arylcyclohexylamine class, with structural similarity to
ketamine and methoxetamine. Historically, it was synthesised in 1962 in an
attempt to develop a short-acting phencyclidine derivative, a project that
culminated in the discovery of ketamine.4
Drugs of this class are known to possess N-methyl-D-aspartate receptor
antagonist activity with variable effects towards other receptors,4 resulting in dissociative effects clinically. The use
of this drug has been recently reported in Germany.5 To date, there have been no clinical poisoning reports
of this drug in the scientific literature, but user reports on the
internet show that 2-oxo-PCE causes a similar effect to ketamine, but is
more potent.
Ketamine is one of the most prevalent drugs of
abuse in Hong Kong. Our findings of 2-oxo-PCE in a cluster of unrelated
patients with suspected ketamine abuse give rise to the suspicion of
substitution of 2-oxo-PCE for ketamine in street supplies, possibly to
evade detection. In patients presenting with ketamine-like toxidrome but
with a negative urine toxicology result, the use of 2-oxo-PCE may need to
be considered. Analysis of 2-oxo-PCE in urine specimens is provided in our
laboratory and can be requested by clinicians in Hong Kong.
Declaration
All authors have disclosed no conflicts of
interest.
References
1. Lau NK, Chong YK, Tang MH, Ching CK, Mak
TW. Desoxy-D2PM: a novel psychoactive substance in convenience stores.
Hong Kong Med J 2016;22:515. Crossref
2. Tang M, Ching CK, Tse ML, et al.
Surveillance of emerging drugs of abuse in Hong Kong: validation of an
analytical tool. Hong Kong Med J 2015;21:114-23. Crossref
3. Poon WT, Lai CF, Lui MC, Chan AY, Mak
TW. Piperazines: a new class of drug of abuse has landed in Hong Kong.
Hong Kong Med J 2010;16:76-7.
4. Morris H, Wallach J. From PCP to MXE: a
comprehensive review of the non-medical use of dissociative drugs. Drug
Test Anal 2014;6:614-32. Crossref
5. Piontek D, Hannemann TV.
Medikamentenmissbrauch und der Konsum von neuen psychoaktiven Substanzen
(NPS) in unterschiedlichen Risikopopulationen. Ergebnisse des Projekts
Phar-Mon NPS aus den Jahren 2015 und 2016 [in German]. München: IFT
Institut für Therapieforschung; 2017.