Zopiclone
From Wikipedia, the free encyclopedia
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Zopiclone
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| Systematic (IUPAC) name | |
| [8-(5-chloropyridin-2-yl)- 7-oxo-2,5,8-triazabicyclo [4.3.0]nona-1,3,5-trien-9-yl] 4- methylpiperazine-1-carboxylate | |
| Identifiers | |
| CAS number | 43200-80-2 |
| ATC code | N05CF01 |
| PubChem | 5735 |
| DrugBank | APRD00356 |
| Chemical data | |
| Formula | C17H17ClN6O3 |
| Mol. weight | 388.808 g/mol |
| Pharmacokinetic data | |
| Bioavailability | 52-59% bound to plasma protein |
| Metabolism | Various cytochrome P450 liver enzymes |
| Half life | ~6 hours ~9 hours for over 65 |
| Excretion | Urine |
| Therapeutic considerations | |
| Pregnancy cat. |
C |
| Legal status |
USA DEA Schedule IV |
| Routes | Oral tablets 7.5 mg |
Zopiclone (sold as Imovane®, Zimovane®) is a novel hypnotic agent used in the treatment of insomnia. It was first developed by Sepracor and introduced in 1988 by Rhône-Poulenc S.A., now part of Sanofi-Aventis. Zopiclone is a controlled substance in the United States, Canada and some European countries and may be illegal to possess without a prescription.
While it acts on the BZ1 receptor and is a short-acting hypnotic agent, it is not a benzodiazepine, but a cyclopyrrolone derivative, belonging to a novel chemical class which is structurally unrelated to existing hypnotics.
On April 4, 2005, the DEA listed zopiclone under Schedule IV, due to some evidence that the drug has addictive properties similar to benzodiazepines.
Zopiclone, as traditionally sold worldwide, is a racemic mixture of two stereoisomers, only one of which is active. In 2005, the pharmaceutical company Sepracor began marketing the active stereoisomer eszopiclone under the name Lunesta in the United States. This had the consequence of placing what is a generic drug in most of the world under patent control in the United States. The eszopiclone/zopiclone difference is in the dosage - the strongest eszopiclone dosage contains 3-mg of the therapeutic stereoisomer, whereas, the highest zopiclone dosage (7.5-mg) contains 3.75-mg of the active stereoisomer. The two agents have not been studied via head-to-head clinical trials to determine if any clinical differences exist (e.g., efficacy, side-effects, etc.).
Zopiclone is known colloquially as a 'Z drug', Other Z drugs include zaleplon and zolpidem and were thought in initial studies to be less addictive and less habit forming than benzodiazepines. This appraisal has shifted somewhat in the last few years, as cases of addiction and habituation have been presented. It is recommended that zopiclone is taken on a "when required" basis, and daily or continuous use of the drug is not usually advised.
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[edit] Adverse reactions
The side-effect most commonly seen in clinical trials is taste alteration or dysgeusia (bitter, metallic taste). Palpitations may occur in the daytime after withdrawal from the drug after prolonged periods of use (>4 weeks).
[edit] More common reactions:
Gastrointestinal: bitter metallic taste, dry mouth. Nervous system: drowsiness, headaches, fatigue. Mood changes have been noted which if experienced should lead to the drug being withdrawn from the patient.
[edit] Less common reactions:
Gastrointestinal: heartburn, constipation, diarrhoea, nausea, coated tongue, bad breath, anorexia or increased appetite, vomiting, epigastric pains, dyspepsia, dehydration. Cardiovascular: palpitations in elderly patients. Skin: urticaria, tingling. Miscellaneous: blurred vision, micturition, mild to moderate increases in serum transaminases and/or alkaline phosphatase have been reported very rarely. Reproductive: impotence, ejaculation failure. Nervous system: agitation, anxiety, loss of memory including retrograde amnesia, confusion, dizziness, weakness, somnolence, asthenia, feeling of drunkenness, depression, coordination abnormality, hypotonia, speech disorder, hallucinations (auditory and visual), behavioural disorders, aggression, tremor, rebound insomnia, nightmares, hypomania.
