Non-fatal intoxications involving the novel benzodiazepine clonazolam: case series from the Emerging Drugs Network of Australia – Victoria project

Abstract

Introduction

Clonazolam is an unregistered novel benzodiazepine which emerged in global illicit drug markets in 2014. We describe the clinical features of four cases of non-fatal clonazolam mono-intoxications from patients presenting to emergency departments in Australia.

Cases

Four patients aged between 16 and 19 years presented to hospital with a sedative toxidrome (Glasgow Coma Scale range 8–13) and elevated heart rate (median heart rate 100 beats per minute, range 92–105) following reported benzodiazepine exposure. Three patients reported the use of a large quantity (7–20 tablets) of Xanax^®, a brand of alprazolam not commercially available in Australia. Two patients required nasopharyngeal airway insertion following the development of airway obstruction. The median time to return of a normal conscious state (Glasgow Coma Scale 15) was 23 h (range 5–30 h). Clonazolam (range 0.2–2.1 µg/L) and its main metabolite 8-aminoclonazolam (range 5.9–19.1 µg/L) were the only substances detected by liquid chromatography-tandem mass spectrometry in blood samples of all patients.

Conclusion

Clonazolam intoxication resulted in sedation with mild sinus tachycardia. Three patients who reported multiple tablet exposures experienced prolonged sedation, and two of these patients developed airway obstruction. In this series, clonazolam was unknowingly ingested through possible illicit substitution within an unregulated counterfeit benzodiazepine product.

Keywords:

• NPS
• new psychoactive substance
• novel benzodiazepine
• clonazolam
• early warning system
• toxicosurveillance

Acknowledgements

The authors additionally thank all EDNAV project site investigators for their assistance in case collection and Dr Linda Glowacki and Miss Samantha Joubert from the Victorian Institute of Forensic Medicine for their analytical assistance.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors acknowledge funding from the Victorian Department of Health and the National Health and Medical Research Council (APP2001107).