Meclonazepam ((S)-3-methylclonazepam) was discovered by a team at Hoffmann-La Roche in the 1970s and is a drug which is a benzodiazepine derivative similar in structure to clonazepam.
It has sedative and anxiolytic actions like those of other benzodiazepines.
Meclonazepam was never used as medicine and instead appeared online as a designer drug.