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.