Zopiclone

zopiclone (also known by the trade names zimovane and imovane) is a non-benzodiazepine hypnotic substance of the cyclopyrrolone class that is primarily used in the treatment of insomnia. zopiclone is known to belong to a family of drugs colloquially known as “z-drugs”. other z-drugs include zaleplon (sonata) and zolpidem (ambien and ambiencr).

zopiclone is thought to increase the normal neurotransmission of the neurotransmitter gaba in the central nervous system in a similar yet distinct way to the activity of benzodiazepines. as zopiclone displays heavy sedating effects, it is has been approved for and is commonly sold as a sleeping pill.

while “z-drugs” were initially thought to have less misuse potential than benzodiazepines, this appraisal has shifted somewhat in the last few years as a number of cases of addiction and habituation have been observed. zopiclone, like all “z-drugs”, is recommended to be taken on a short-term basis — usually a week or less. daily or continuous use of the drug is usually not advised.

chemistry

zopiclone is a hypnotic nonbenzodiazepine drug of the cyclopyrrolone class. zopiclone and its closely related dextrorotatory s-stereoisomer zopiclone (lunesta) are the most popular and available cyclopyrrolone drugs. this class of drugs is named for having a pyrrolone core, a five-membered ring with a nitrogen constituent (pyrrole) and a ketone group (-one).

the ketone group found in zopiclone is located at r₅ of the pyrrolone ring. zopiclone contains four nitrogenous rings including pyrrolone. fused to the pyrrolone core is a pyrazine ring, a six-membered aromatic ring with two nitrogen substituents. the two rings are fused at r₃ and r₄. this bicylic core is called a pyrollopyrazine. bound to the nitrogen group of the pyrrolone at r₆ is a substituted pyridine ring. pyridine is six-membered unsaturated ring with one nitrogen group. the pyridine ring of zopiclone is substituted at r₅ with a chlorine group.

the final ring of zopiclone is a piperazine ring. piperazine is a six-membered saturated ring with two nitrogen constituents; in this case, it is substituted at r₄ with a methyl group. this piperazine ring is connected to the pyrrolone core of zopiclone at r₇ through a carboxylate group.

pharmacology

zopiclone, although structurally different from benzodiazepines, shares an almost identical pharmacological profile to them. its mechanism of action works by binding to the same site as benzodiazepines and acts as a full agonist, which in turn positively modulates benzodiazepine-sensitive gaba_a receptors and enhances gaba binding at the gaba_a receptors to produce zopiclone’s subjective effects. since gaba functions as the brain’s predominant inhibitory neurotransmitter, this activation of receptors results in the sedative and anxiolytic effects of zopiclone.