2-oxo-PCE: ketamine analogue on the streets

Fluorodeschloroketamine found as a street drug in drug seizures and drug driving cases in Hong Kong

BACKGROUND

With the decline of the use of ketamine, one of the common drugs of abuse in Hong Kong, detection of ketamine-related analogues in local laboratories has been encountered.

AIM

A brief account of the occurrence of fluorodeschloroketamine (FDCK) in forensic cases is reported through a retrospective study of all drug seizures and driving under the influence of drugs (DUID) cases since its first appearance.

METHODS

Identification of FDCK in drug seizures was achieved through gas chromatography - mass spectrometry (GC-MS) and/or liquid chromatography - diode array detection (LC-DAD) methods while its quantification was performed using gas chromatography - flame ionization detection (GC-FID). For the analysis of blood samples in DUID cases, identification and quantification were performed using LC-MS/MS by monitoring the respective transitions of FDCK and fluorodeschloronorketamine (FDCNK) using ketamine-d4 and norketamine-d4 respectively as internal standards.

RESULTS

Since its first submission in November 2018, a total of 74 drug seizure cases (151 items) and 6 drug driving cases were encountered till December 2019. Drug seizures found with FDCK were physically similar to those of ketamine seizures. The majority of items were detected with FDCK only (103 items, ∼67%) or as a mixture of FDCK with ketamine (42 items, ∼28%). The drug purity detected with either FDCK only or FDCK mixed with ketamine was high which was similar to those purity found in ketamine seizures. The blood drug concentrations of FDCK of the 6 drug driving cases were in the range of <0.002-1.1 μg/mL and other psychoactive drug(s)/metabolite(s) were also identified. Except for one case where the analysis of the metabolite, fluorodeschloronorketamine (FDCNK), was not conducted due to insufficient sample, the FDCK (FDCNK) concentrations in blood found in the 6 cases were <0.002 (0.005), 0.002 (0.002), 0.002 (0.003), 0.02 (0.035), 0.87 (0.44) and 1.1 (not determined) μg/mL.

CONCLUSIONS

With the drug seizures found with FDCK resembled in physical appearance with ketamine seizures, users might likely misuse it as ketamine. Though complicated by other drugs found, it is speculated that the two cases with higher concentration of FDCK found in blood (1.1 and 0.87 μg/mL) might have contributed to the impairment observed.

Qualitative Screening of Amphetamine- and Ketamine-Type Abuse Drugs in Urine Employing Dual Mode Extraction Column by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS-MS)

This manuscript reported a fast and rapid qualitative screening method for abuse drugs in urine by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The scope of the abuse drugs under investigation included methamphetamine (MA), amphetamine (AMP), methylenedioxymethamphetamine (MDMA), methylenedioxyamphetamine (MDA), paramethoxymethamphetamine (PMMA), ephedrine, pseudoephedrine, ketamine (KET), deschloroketamine (DCK), 2-fluorodeschloroketamine (2 F-DCK) and deschloro-N-ethylketamine (2-oxo-PCE). The method employed a dual mode extraction (DME) column as a novel clean-up method for the urine matrix. To an aliquot of 0.2 mL urine, internal standards (ISTDs) and 0.4 mL of acidified methanol were added. After vortex and centrifugation, the supernatant was passed through a DME column before LC-MS-MS analysis. Chromatographic separation was achieved with a C18 column by gradient elution. The limits of detection (LODs) for MA, AMP, MDMA, MDA and PMMA were 3 ng/mL, whereas those for ephedrine and pseudoephedrine were 10 ng/mL and those for KET, DCK, 2 F-DCK and 2-oxo-PCE were 1 ng/mL. The matrix effects ranged from -12% to 7% (%CV from 4% to 19%). This method is fit for the intended purpose for forensic toxicology, as well as for forensic analysis of drugs facilitating sexual assault and other criminal acts.

Arylcyclohexylamine Derivatives: Pharmacokinetic, Pharmacodynamic, Clinical and Forensic Aspects

Since the 2000s, an increasing number of new psychoactive substances (NPS) have appeared on the drug market. Arylcyclohexylamine (ACH) compounds such as ketamine, phencyclidine and eticyclidine derivatives are of particular concern, given their rapidly increasing use and the absence of detailed toxicity data. First used mainly for their pharmacological properties in anesthesia, their recreational use is increasing. ACH derivatives have an antagonistic activity against the N-methyl-D-aspartate receptor, which leads to dissociative effects (dissociation of body and mind). Synthetic ketamine derivatives produced in Asia are now arriving in Europe, where most are not listed as narcotics and are, thus, legal. These structural derivatives have pharmacokinetic and pharmacodynamic properties that are sometimes very different from ketamine. Here, we describe the pharmacology, epidemiology, chemistry and metabolism of ACH derivatives, and we review the case reports on intoxication.

Overdoses and deaths related to the use of ketamine and its analogues: a systematic review

Background: Although the misuse of ketamine constitutes a worldwide issue, ketamine is quickly taking its place as a therapeutic option in the management of several mental disorders. However, the use of ketamine and/or its analogues, as well as combinations with other drugs, can be fatal.Objective: To outline the cases of overdoses and deaths related to the use of ketamine and/or its analogues, as reported in the scientific literature. To investigate if ketamine is safe in a therapeutic context, particularly in its use as an antidepressant.Methods: Electronic searches were performed on three medical databases. Articles describing cases of overdose and/or death associated with ketamine and/or its analogues were included. After the removal of duplicates, title analysis and full-text analysis, 34 articles were included in this review.Results: Eighteen articles described fatal cases and sixteen described overdoses. Poly-substance use was mentioned in 53% of the selected articles. Most cases were males and the ages varied from two to 65 years old. A total of 312 overdose cases and 138 deaths were reported. In both death reports and overdose cases, ketamine was preponderant: 89.1% and 79%, respectively. No cases of overdose or death related to the use of ketamine as an antidepressant in a therapeutic setting were found; most of the deaths occurred in the circumstances of polydrug use and overdoses left no sequelae.Conclusion: There is legitimate concern about the risks involving the use of ketamine and its analogues, especially in recreational settings. On the other hand, ketamine as medicine is considered safe and it is listed as an essential medicine by the World Health Organization. Although clinicians must remain vigilant, this should not deter appropriate prescription.

Prevalence of drugs of abuse found in forensic testing of illicit drug seizures and urine samples from offenders/probationers in Hong Kong: A 3-year update

The study investigates the prevalence of drugs of abuse detected from 2016 to 2018 through i) forensic drug testing of seizures from law enforcement agencies, and ii) common drugs of abuse for urinalysis of samples obtained from offenders/probationers under mandatory drug-use surveillance programmes. Under the selected drug testing groups, an average of 4677 cases/year (c.f. 5334 cases/year in 2011-2015) of illicit drug seizures and 19,501 samples/year (c.f. 28,438 samples/year in 2011-2015) for urinalysis, were examined from 2016 to 2018. The three most commonly encountered abused drugs in the period in both types of examinations were methamphetamine (MA), cocaine and heroin. The occurrence of ketamine, the most prevalent drug [1815 (34.0%) cases/year (for drug seizures), 2074 (7.3%) samples/year (for urinalysis)] in 2011-2015, had dropped significantly to 487 (10.4%) cases/year and 350 (1.8%) samples/year respectively. The drug positive rates for urinalysis in the selected population group (i.e., offenders/probationers requiring mandatory drug testing) increased steadily from 27.3% in 2016 to 30.8% in 2018 (an average of 29.0% vs. 22.1% in 2011-2015). The ratio of single drug use to more than one drug was about 4:1, showing predominant use of single drug. While MA was the most prevalent drug in the period, cases found with cocaine and cannabis increased steadily over the past 3 years. A rising trend was noted for cases identified with new psychoactive substances (NPS) in illicit drug seizures from an average of 87 cases/year in 2011-2015 to 211 cases/year in 2016-2018 although NPS cases still contributed to less than 5% of overall drug seizures. A total of 69 substances classified as NPS were encountered with 47 NPS newly encountered in 2016-2018 but 25 NPS found in 2011-2015 disappeared in this 3-year period. Cathinones, including both synthetic and plant-based, continued to be the major category of NPS cases (∼72%) in the region followed by synthetic cannabinoids, ketamine/PCP analogs and synthetic opioids.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.

The Emergence of Deschloro-N-ethyl-ketamine, a Ketamine Analog, in Drug Seizures and Drug Driving Cases in Hong Kong

The study reports the detection of a newly emerged drug, deschloro-N-ethyl-ketamine (2-oxo-PCE), an analog of ketamine, through forensic drug and toxicological examinations of exhibits from drug seizure cases and blood samples taken from drivers of driving under the influence of drug (DUID) cases, respectively, in Hong Kong. The submission of 2-oxo-PCE in both types of cases was firstly encountered in October 2017. A total of 31 drug seizure cases (52 items) and 4 DUID cases were found positive with 2-oxo-PCE till October 2018. Drug seizures with 2-oxo-PCE found were all in physical form (mostly in powdery or crystalline solid), resembling those samples commonly found with ketamine but having much lower purity. Although the majority of the relevant items was found with 2-oxo-PCE as the only psychoactive substance (36 items, ~69%) or as a mixture with ketamine (10 items, ~19%), other psychoactive substances including methamphetamine, methylenedioxymethamphetamine and pentylone have also been encountered (6 items, 12%). For the four DUID cases, 2-oxo-PCE and its metabolite, deschloronorketamine, were detected in all blood samples. The 2-oxo-PCE concentrations in the four blood samples were in the range of 0.08–0.31 μg/mL, being higher than the concentrations of deschloronorketamine (in the range of 0.04–0.09 μg/mL) for each sample. The 2-oxo-PCE levels found were generally lower than the ketamine levels found in reported DUID cases. With items found with 2-oxo-PCE, which were physically indistinguishable from ketamine but having lower drug purity in seizures, the lower 2-oxo-PCE blood levels with more severe impairment signs observed for the drivers in DUID cases, it is not unreasonable to speculate that users might have taken it as ketamine without knowing of its real identity and hence was adversely affected by the more potent 2-oxo-PCE.

Novel ketamine analogues cause a false positive phencyclidine immunoassay

Background

Immunoassays are commonly used to test for drugs of abuse in patients in a variety of settings. The increasing prevalence of ‘designer’ drugs causes difficulties for the toxicology laboratory and may result in unexpected false positives and identification of unfamiliar compounds. Within the past decade, there have been a variety of ketamine and phencyclidine analogues identified, particularly as drugs of abuse.

Method

We present a case of intoxication with a novel ketamine analogue, deschloro-N-ethyl-ketamine, causing a false positive phencyclidine immunoassay. Additionally, we performed spiking studies and 2D molecular similarity calculations for deschloro-N-ethyl-ketamine, ketamine and three other analogues on the Siemens Viva-E EMIT-II phencyclidine assay to assess their cross-reactivity.

Results

Four of the tested compounds (deschloro-N-ethyl-ketamine, 3-methoxy-phencyclidine, 3-methoxy-eticyclidine and methoxetamine) cause false positive phencyclidine immunoassay results, while ketamine gives a negative result. The cross-reactivity data are in accord with the similarity calculations of these molecules, further validating the ability of 2D molecular similarity analysis to predict the molecular cross-reactivity in immunoassays.

Conclusions

The cross-reactivity data of phencyclidine and ketamine analogues presented in this study could help toxicology laboratories and clinicians in evaluating unexpected results, particularly when novel PCP and ketamine analogues are being considered.

Hong Kong Poison Information Centre: Annual report 2017

Objectives:

To report and analyse the poisoning data of Hong Kong Poison Information Centre in 2017.

Methods:

In 2017, all poisoning cases received by Hong Kong Poison Information Centre were retrieved from its database (Poison Information and Clinical Management System) for analysis.

Results:

A total of 3956 poisoned cases were analysed. There were 1789 male patients (45.2%), 2159 female patients (54.6%) and 8 sex-unspecified patients (0.2%). The majority of cases (59.9%) were between 20 and 59 years old. The common causes of poisoning were suspected self-harm/suicidal attempt (36.2%), unintentional exposure (18.6%) and abusive substance use (13.7%). Excluding the common co-ingestant ethanol, the five commonest types of poison were benzodiazepines, paracetamol, zopiclone, Chinese herbal medicine and household products. Most patients were managed with supportive measures, while 17.4% and 13.2% of consultation cases were treated by decontamination and antidotes, respectively. The majority of the cases had uneventful recovery; 1.1% resulted in death and 4.3% had major outcomes. A total of 13 interesting cases and 1 poisoning outbreak were discussed.

Conclusion:

This 12th annual report provided the updated epidemiological information on poisoning pattern in Hong Kong and highlighted important changes in comparison with our previous reports.

9-year review of new psychoactive substance use in Hong Kong: A clinical laboratory perspective

Background:

New psychoactive substances are constantly evolving structural analogues of traditional drugs of abuse that have become a threat to public health worldwide and within our locality. An understanding of the local pattern of new psychoactive substance use will help guide frontline clinical management.

Objectives:

This study was conducted to review the new psychoactive substances detected in cases referred to the authors’ laboratory (a tertiary clinical toxicology centre), as well as the associated clinical features and toxicological findings.

Methods:

All cases referred to the laboratory for toxicology analysis between January 2009 and December 2017, and which were analytically confirmed to involve new psychoactive substance use, were retrospectively reviewed. Demographic data, clinical features and toxicology findings were studied.

Results:

A total of 111 cases involving 104 patients and 22 types of new psychoactive substances were identified, with an increasing trend in the number of cases and subclass of new psychoactive substances detected. Up to half of the cases (n = 64) were related to the use of 2-phenyl-2-(ethylamino)-cyclohexanone (2-oxo-PCE, a ketamine analogue); other new psychoactive substances detected included para-methoxymethamphetamine, 4-fluoroamphetamine, phenazepam, 3-trifluoromethylphenylpiperazine, 5-methoxy-diisopropyltryptamine, 2-diphenylmethylpyrrolidine, methoxyphenidine, the N-methoxybenzyl drugs, cathinones, synthetic cannabinoids and opioids. Among the acute poisoning cases attributable to new psychoactive substance use, the severity was fatal (n = 3), severe (n = 17), moderate (n = 67) and minor (n = 17). And 11 patients required intensive care unit admission. All three fatal cases were associated with para-methoxymethamphetamine use.

Conclusion:

A rising trend of new psychoactive substance use is observed locally, which is associated with considerable morbidity and mortality. Continued vigilance from frontline clinicians and medical professionals is imperative in the combat against new psychoactive substance use.