Clonazolam: a novel liquid benzodiazepine

Clonazolam is a designer triazolobenzodiazepine first synthesized in the 1970s that has never been licensed for therapeutic use. Clonazolam first surfaced on the internet in 2014 as a drug of abuse. Cases of intoxication involving clonazolam have been identified since 2016 in Europe with a single case described in the US in 2017. It is typically found in tablet, capsule, pellet, blotter, or powder form. A 28-year-old man presented with somnolence to an emergency department after reportedly ingesting one-half of a 30 mL vial of liquid clonazolam he purchased from the internet. He had normal vital signs and had no distress on presentation. His laboratory tests were normal, and his mental status cleared during a 6-hour observation in the emergency department. Non-targeted analysis of the liquid using liquid chromatography-quadrupole time-of-flight mass spectrometry identified clonazolam (0.4 mg/mL) with no other pharmaceuticals. This is the second case of intentional clonazolam ingestion described in the United States, and is unique in that the substance was found in liquid form. Providers should be aware that clonazolam is available on the internet in liquid formulation, which may increase the risk of accidental overdose.