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Information |
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Drug Groups
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approved |
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Description
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Zopiclone is a novel hypnotic agent used in the treatment of insomnia. Its mechanism of action is based on modulating benzodiazepine receptors. In addition to zopiclone's benzodiazepine pharmacological properties it also has some barbiturate like properties. |
| Indication |
For the short-term treatment of insomnia. |
| Pharmacology |
Zopiclone is a nonbenzodiazepine hypnotic from the pyrazolopyrimidine class and is indicated for the short-term treatment of insomnia. While Zopiclone is a hypnotic agent with a chemical structure unrelated to benzodiazepines, barbiturates, or other drugs with known hypnotic properties, it interacts with the gamma-aminobutyric acid-benzodiazepine (GABABZ) receptor complex. Subunit modulation of the GABABZ receptor chloride channel macromolecular complex is hypothesized to be responsible for some of the pharmacological properties of benzodiazepines, which include sedative, anxiolytic, muscle relaxant, and anticonvulsive effects in animal models. Zopiclone binds selectively to the brain alpha subunit of the GABA A omega-1 receptor. |
| Toxicity |
Rare individual instances of fatal outcomes following overdose with racemic zopiclone have been reported in European postmarketing reports, most often associated with overdose with other CNS-depressant agent. Signs and symptoms of overdose effects of CNS depressants can be expected to present as exaggerations of the pharmacological effects noted in preclinical testing. |
| Affected Organisms |
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Humans and other mammals |
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| Biotransformation |
Extensively metabolized in the liver via decarboxylation (major pathway), demethylation, and side chain oxidation. Metabolites include an N-oxide derivative (weakly active; approximately 12% of a dose) and an N-desmethyl metabolite (inactive; approximately 16%). Approximately 50% of a dose is converted to other inactive metabolites via decarboxylation. Hepatic microsomal enzymes are apparently not involved in zopiclone clearance. |
| Absorption |
Rapidly absorbed following oral administration. |
| Half Life |
Elimination half life is approximately 5 hours (range 3.8 to 6.5 hours) and is prolonged to 11.9 hours in patients with hepatic insufficiency. |
| Protein Binding |
Approximately 45% |
| References |
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Liu HJ, Sato K, Shih HC, Shibuya T, Kawamoto H, Kitagawa H: Pharmacologic studies of the central action of zopiclone: effects on locomotor activity and brain monoamines in rats. Int J Clin Pharmacol Ther Toxicol. 1985 Mar;23(3):121-8.
[Pubmed]
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Sato K, Hong YL, Yang MS, Shibuya T, Kawamoto H, Kitagawa H: Pharmacologic studies of central actions of zopiclone: influence on brain monoamines in rats under stressful condition. Int J Clin Pharmacol Ther Toxicol. 1985 Apr;23(4):204-10.
[Pubmed]
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Dundar Y, Dodd S, Strobl J, Boland A, Dickson R, Walley T: Comparative efficacy of newer hypnotic drugs for the short-term management of insomnia: a systematic review and meta-analysis. Hum Psychopharmacol. 2004 Jul;19(5):305-22.
[Pubmed]
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Blanchard JC, Julou L: Suriclone: a new cyclopyrrolone derivative recognizing receptors labeled by benzodiazepines in rat hippocampus and cerebellum. J Neurochem. 1983 Mar;40(3):601-7.
[Pubmed]
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Julou L, Bardone MC, Blanchard JC, Garret C, Stutzmann JM: Pharmacological studies on zopiclone. Pharmacology. 1983;27 Suppl 2:46-58.
[Pubmed]
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