Zopiclone, a nonbenzodiazepine hypnotic belonging to the pyrazolopyrimidine class, is employed for the short-term management of insomnia. Operating outside the benzodiazepine and barbiturate realms, it interacts with the gamma-aminobutyric acid-benzodiazepine (GABABZ) receptor complex, demonstrating both benzodiazepine-like and some barbiturate-like properties. By selectively binding to the brain alpha subunit of the GABA A omega-1 receptor, zopiclone's action unfolds through engagement with the benzodiazepine receptor complex and modulation of the GABABZ receptor chloride channel macromolecular complex. Its effects align with those of benzodiazepines, acting as full agonists on various GABAA receptor subunits (α1, α2, α3, α5), amplifying GABA's inhibitory actions to produce therapeutic (hypnotic and anxiolytic) and adverse outcomes. Primarily metabolized through processes like decarboxylation, demethylation, and side chain oxidation in the liver, zopiclone undergoes substantial metabolic transformation. This results in the formation of metabolites such as a weakly active N-oxide derivative (constituting around 12% of the dose) and an inactive N-desmethyl metabolite (approximately 16% of the dose). Moreover, nearly 50% of the dose is converted to additional inactive metabolites via decarboxylation, with hepatic microsomal enzymes seemingly playing no significant role in zopiclone clearance. Renowned for its distinct mechanism within the realm of nonbenzodiazepine hypnotics, zopiclone effectively addresses short-term insomnia management.

Zopiclone Pathway References