Zopiclone Explained

Watchedfields:changed
Verifiedrevid:458773669
Iupac Name:(RS)-6-(5-chloropyridin-2-yl)-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-''b'']pyrazin-5-yl 4-methylpiperazine-1-carboxylate
Width:200
Width2:230
Tradename:Imovane, Zimovane, Dopareel, others
Pregnancy Au:C
Pregnancy Us:C
Legal Au:S4
Legal Br:B1
Legal Br Comment:[1]
Legal Ca:Rx-only
Legal Uk:Class C
Legal Nz:Class C
Legal Us:Schedule IV
Legal Status:Rx-only
Routes Of Administration:Oral tablets, 3.75 mg or 7.5mg (UK), 5 mg, 7.5 mg, or 10 mg (JP)
Bioavailability:75–80%[2]
Protein Bound:52–59%
Metabolism:Hepatic through CYP3A4 and CYP2E1
Elimination Half-Life:~5 hours (3.5–6.5 hours)
~7–9 hours for 65+ years old
Excretion:Urine (80%)
Iuphar Ligand:7430
Cas Number:43200-80-2
Atc Prefix:N05
Atc Suffix:CF01
Pubchem:5735
Drugbank:DB01198
Chemspiderid:5533
Unii:03A5ORL08Q
Kegg:D01372
Chebi:32315
Chembl:135400
Pdb Ligand:ZPC
C:17
H:17
Cl:1
N:6
O:3
Smiles:O=C(OC3c1nccnc1C(=O)N3c2ncc(Cl)cc2)N4CCN(C)CC4
Stdinchi:1S/C17H17ClN6O3/c1-22-6-8-23(9-7-22)17(26)27-16-14-13(19-4-5-20-14)15(25)24(16)12-3-2-11(18)10-21-12/h2-5,10,16H,6-9H2,1H3
Stdinchikey:GBBSUAFBMRNDJC-UHFFFAOYSA-N

Zopiclone, sold under the brand name Imovane among others, is a nonbenzodiazepine, specifically a cyclopyrrolone, used to treat difficulty sleeping. Zopiclone is molecularly distinct from benzodiazepine drugs and is classed as a cyclopyrrolone. However, zopiclone increases the normal transmission of the neurotransmitter gamma-aminobutyric acid (GABA) in the central nervous system, via modulating GABAA receptors similarly to the way benzodiazepine drugs do inducing sedation but not with the anti-anxiety properties of the benzodiazepines.

Zopiclone is a sedative. It works by causing a depression or tranquilization of the central nervous system. After prolonged use, the body can become accustomed to the effects of zopiclone. When the dose is then reduced or the drug is abruptly stopped, withdrawal symptoms may result. These can include a range of symptoms similar to those of benzodiazepine withdrawal. Although withdrawal symptoms from therapeutic doses of zopiclone and its isomers (i.e., eszopiclone) do not typically present with convulsions and are therefore not considered life-threatening, patients may experience such significant agitation or anxiety that they seek emergency medical attention.

In the United States, zopiclone is not commercially available,[3] although its active stereoisomer, eszopiclone, is. Zopiclone is a controlled substance in the United States, Japan, Brazil, New Zealand and some European countries, and may be illegal to possess without a prescription.

Zopiclone is known colloquially as a "Z-drug". Other Z-drugs include zaleplon and zolpidem and were initially thought to be less addictive than benzodiazepines. However, this appraisal has shifted somewhat in the last few years as cases of addiction and habituation have been presented. Zopiclone is recommended to be taken at the lowest effective dose, with a duration of 2–3 weeks for short-term insomnia.[4] Daily or continuous use of the drug is not usually advised, and caution must be taken when the compound is used in conjunction with benzodiazepines, sedatives or other drugs affecting the central nervous system.[5]

Medical uses

Zopiclone is used for the short-term treatment of insomnia where sleep initiation or sleep maintenance are prominent symptoms. Long-term use is not recommended, as tolerance, dependence, and addiction can occur.[6] [7] One low-quality study found that zopiclone is ineffective in improving sleep quality or increasing sleep time in shift workers, and more research in this area has been recommended.[8]

Cognitive behavioral therapy has been found to be superior to zopiclone in the treatment of insomnia and has been found to have lasting effects on sleep quality for at least a year after therapy.[9] [10] [11] [12]

Specific populations

Elderly

Zopiclone, similar to other benzodiazepines and nonbenzodiazepine hypnotic drugs, causes impairments in body balance and standing steadiness in individuals who wake up at night or the next morning. Falls and hip fractures are frequently reported. The combination with alcohol consumption increases these impairments. Partial, but incomplete tolerance develops to these impairments.[13] Zopiclone increases postural sway and increases the number of falls in older people, as well as cognitive side effects. Falls are a significant cause of death in older people.[14] [15] [16]

An extensive review of the medical literature regarding the management of insomnia and the elderly found that considerable evidence of the effectiveness and lasting benefits of nondrug treatments for insomnia exist. Compared with the benzodiazepines, the nonbenzodiazepine sedative-hypnotics, such as zopiclone, offer few if any advantages in efficacy or tolerability in elderly persons. Newer agents such as the melatonin receptor agonists may be more suitable and effective for the management of chronic insomnia in elderly people. Long-term use of sedative-hypnotics for insomnia lacks an evidence base and is discouraged for reasons that include concerns about such potential adverse drug effects as cognitive impairment (anterograde amnesia), daytime sedation, motor incoordination, and increased risk of motor vehicle accidents and falls. In addition, the effectiveness and safety of long-term use of nonbenzodiazepine hypnotic drugs remains to be determined.[17]

Liver disease

Patients with liver disease eliminate zopiclone much more slowly than normal patients and in addition experience exaggerated pharmacological effects of the drug.[18]

Adverse reactions

Sleeping pills, including zopiclone, have been associated with an increased risk of death.[19] The British National Formulary states adverse reactions as follows: "taste disturbance (some report a metallic taste); less commonly nausea, vomiting, dizziness, drowsiness, dry mouth, headache; rarely amnesia, confusion, depression, hallucinations, nightmares; very rarely light headedness, incoordination, paradoxical effects [...] and sleep-walking also reported".

Contraindications

Zopiclone causes impaired driving skills similar to those of benzodiazepines. Long-term users of hypnotic drugs for sleep disorders develop only partial tolerance to adverse effects on driving, with users of hypnotic drugs even after one year of use still showing an increased motor vehicle accident rate.[20] Patients who drive motor vehicles should not take zopiclone as there is a significantly increased risk of accidents in zopiclone users.[21] Zopiclone induces impairment of psychomotor function.[22] [23] Driving or operating machinery should be avoided after taking zopiclone as effects can carry over to the next day, including impaired hand-eye coordination.[24] [25]

A double-blind study on the effect on performance of several hypnotic medications, relevant to military personnel who may have to be awakened to carry out duties, found that drugs listed in increasing order of performance impact duration were melatonin (with no impact), zaleplon, temazepam, and zopiclone. The effects on serial reaction time (SRT), logical reasoning (LRT), serial subtraction (SST), and multitask (MT) were measured. For zaleplon (10 mg), zopiclone (7.5 mg) and temazepam (15 mg) respectively the times to recover normal performance for SRT were 3.25,, and 5.25 hours; for LRT 3.25,, and 4.25 hours; for SST 2.25,, and 4.25 hours; and for MT 2.25,, and 3.25 hours. The study did not consider the effectiveness of the drugs on sleep.[26]

EEG and sleep

It causes similar alterations on EEG readings and sleep architecture as benzodiazepines and causes disturbances in sleep architecture on withdrawal as part of its rebound effect.[27] [28] Zopiclone reduces both delta waves and the number of high-amplitude delta waves whilst increasing low-amplitude waves.[29] Zopiclone reduces the total amount of time spent in REM sleep as well as delaying its onset.[30] [31] In EEG studies, zopiclone significantly increases the energy of the beta frequency band, increasing stage 2. Zopiclone is less selective to the α1 site and has higher affinity to the α2 site than zaleplon. Zopiclone is therefore very similar pharmacologically to benzodiazepines.[32]

Overdose

Zopiclone is sometimes used as a method of suicide.[33] It has a similar fatality index to that of benzodiazepine drugs, apart from temazepam, which is particularly toxic in overdose.[34] [35] Deaths have occurred from zopiclone overdose, alone or in combination with other drugs.[36] [37] [38] Overdose of zopiclone may present with excessive sedation and depressed respiratory function that may progress to coma and possibly death.[39] Zopiclone combined with alcohol, opiates, or other central nervous system depressants may be even more likely to lead to fatal overdoses. Zopiclone overdosage can be treated with the GABAA receptor benzodiazepine site antagonist flumazenil, which displaces zopiclone from its binding site, thereby rapidly reversing its effects.[40] [41] Serious effects on the heart may also occur from a zopiclone overdose[42] [43] when combined with piperazine.[44]

Death certificates show the number of zopiclone-related deaths is on the rise.[45] When taken alone, it usually is not fatal, but when mixed with alcohol or other drugs such as opioids, or in patients with respiratory, or hepatic disorders, the risk of a serious and fatal overdose increases.[46] [47]

Interactions

Zopiclone also interacts with trimipramine and caffeine.[48] [49]

Alcohol has an additive effect when combined with zopiclone, enhancing the adverse effects including the overdose potential of zopiclone significantly.[50] Due to these risks and the increased risk for dependence, alcohol should be avoided when using zopiclone.[51]

Erythromycin appears to increase the absorption rate of zopiclone and prolong its elimination half-life, leading to increased plasma levels and more pronounced effects. Itraconazole has a similar effect on zopiclone pharmacokinetics as erythromycin. The elderly may be particularly sensitive to the erythromycin and itraconazole drug interaction with zopiclone. Temporary dosage reduction during combined therapy may be required, especially in the elderly.[52] [53] Rifampicin causes a very notable reduction in half-life of zopiclone and peak plasma levels, which results in a large reduction in the hypnotic effect of zopiclone. Phenytoin and carbamazepine may also provoke similar interactions.[54] Ketoconazole and sulfaphenazole interfere with the metabolism of zopiclone.[55] Nefazodone impairs the metabolism of zopiclone leading to increased zopiclone levels and marked next-day sedation.[56]

Pharmacology

The therapeutic pharmacological properties of zopiclone include hypnotic, anxiolytic, anticonvulsant, and myorelaxant properties.[57] Zopiclone and benzodiazepines bind to the same sites on GABAA receptors, causing an enhancement of the actions of GABA to produce the therapeutic and adverse effects of zopiclone. The metabolite of zopiclone desmethylzopiclone is also pharmacologically active, although it has predominately anxiolytic properties. One study found some slight selectivity for zopiclone on α1 and α5 subunits,[58] although it is regarded as being unselective in its binding to GABAA receptors containing α1, α2, α3, and α5 subunits. Desmethylzopiclone has been found to have partial agonist properties, unlike the parent drug zopiclone, which is a full agonist.[59] The mechanism of action of zopiclone is similar to benzodiazepines, with similar effects on locomotor activity and on dopamine and serotonin turnover.[60] [61] A meta-analysis of randomised controlled clinical trials that compared benzodiazepines to zopiclone or other Z drugs such as zolpidem and zaleplon has found few clear and consistent differences between zopiclone and the benzodiazepines in sleep onset latency, total sleep duration, number of awakenings, quality of sleep, adverse events, tolerance, rebound insomnia, and daytime alertness.[62] Zopiclone is in the cyclopyrrolone family of drugs. Other cyclopyrrolone drugs include suriclone. Zopiclone, although molecularly different from benzodiazepines, shares an almost identical pharmacological profile as benzodiazepines, including anxiolytic properties. Its mechanism of action is by binding to the benzodiazepine site and acting as a full agonist, which in turn positively modulates benzodiazepine-sensitive GABAA receptors and enhances GABA binding at the GABAA receptors to produce zopiclone's pharmacological properties.[63] [64] [65] In addition to zopiclone's benzodiazepine pharmacological properties, it also has some barbiturate-like properties.[66] [67]

Pharmacokinetics

After oral administration, zopiclone is rapidly absorbed, with a bioavailability around 75–80%. Time to peak plasma concentration is 1–2 hours. A high-fat meal preceding zopiclone administration does not change absorption (as measured by AUC), but reduces peak plasma levels and delays its occurrence, thus may delay the onset of therapeutic effects.

The plasma protein-binding of zopiclone has been reported to be weak, between 45 and 80% (mean 52–59%). It is rapidly and widely distributed to body tissues, including the brain, and is excreted in urine, saliva, and breast milk. Zopiclone is partly extensively metabolized in the liver to form an active N-demethylated derivative (N-desmethylzopiclone) and an inactive zopiclone-N-oxide. Hepatic enzymes playing the most significant role in zopiclone metabolism are CYP3A4 and CYP2E1. In addition, about 50% of the administered dose is decarboxylated and excreted via the lungs. In urine, the N-demethyl and N-oxide metabolites account for 30% of the initial dose. Between 7 and 10% of zopiclone is recovered from the urine, indicating extensive metabolism of the drug before excretion. The terminal elimination half-life of zopiclone ranges from 3.5 to 6.5 hours (5 hours on average).

The pharmacokinetics of zopiclone in humans are stereoselective. After oral administration of the racemic mixture, Cmax (time to maximum plasma concentration), area under the plasma time-concentration curve (AUC) and terminal elimination half-life values are higher for the dextrorotatory enantiomers, owing to the slower total clearance and smaller volume of distribution (corrected by the bioavailability), compared with the levorotatory enantiomer. In urine, the concentrations of the dextrorotatory enantiomers of the N-demethyl and N-oxide metabolites are higher than those of the respective antipodes.

The pharmacokinetics of zopiclone are altered by aging and are influenced by renal and hepatic functions.[68] In severe chronic kidney failure, the area under the curve value for zopiclone was larger and the half-life associated with the elimination rate constant longer, but these changes were not considered to be clinically significant.[69] Sex and race have not been found to interact with pharmacokinetics of zopiclone.

Chemistry

The melting point of zopiclone is 178 °C.[70] Zopiclone's solubility in water, at room temperature (25 °C) are 0.151 mg/mL. The logP value of zopiclone is 0.8.

Detection in biological fluids

Zopiclone may be measured in blood, plasma, or urine by chromatographic methods. Plasma concentrations are typically less than 100 μg/L during therapeutic use, but frequently exceed 100 μg/L in automotive vehicle operators arrested for impaired driving ability and may exceed 1000 μg/L in acutely poisoned patients. Post mortem blood concentrations are usually in a range of 400 to 3900 μg/L in victims of fatal acute overdose.[71] [72] [73]

History

Zopiclone was developed and first introduced in 1986 by Rhône-Poulenc S.A., now part of Sanofi, the main worldwide manufacturer. Initially, it was promoted as an improvement on benzodiazepines, but a recent meta-analysis found it was no better than benzodiazepines in any of the aspects assessed.[74] On April 4, 2005, the U.S. Drug Enforcement Administration listed zopiclone under schedule IV, due to 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.[75] [76] In 2005, the pharmaceutical company Sepracor of Marlborough, Massachusetts, 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. Generic forms of Lunesta have since become available in the United States. Zopiclone is currently available off-patent in a number of European countries, Brazil, Canada, Hong Kong, and New Zealand. The eszopiclone/zopiclone difference is in the dosage - the strongest eszopiclone dosage contains 3 mg of the therapeutic stereoisomer, whereas the highest zopiclone dosage (10 mg) contains 5 mg of the active stereoisomer. The two agents have not yet been studied in head-to-head clinical trials to determine the existence of any potential clinical differences (efficacy, side effects, developing dependence on the drug, safety, etc.).

Society and culture

Recreational use

Zopiclone has the potential for non-medical use, dosage escalation, and drug dependence. It is taken orally and sometimes intravenously when used non-medically, and often combined with alcohol to achieve euphoria. Patients abusing the drug are also at risk of dependence. Withdrawal symptoms can be seen after long-term use of normal doses even after a gradual reduction regimen. The Compendium of Pharmaceuticals and Specialties recommends zopiclone prescriptions not exceed 7 to 10 days, owing to concerns of addiction, tolerance, and physical dependence.[77] Two types of drug misuse can occur: either recreational misuse, wherein the drug is taken to achieve a high, or when the drug is continued long-term against medical advice.[78] [79] Zopiclone may be more addictive than benzodiazepines.[80] Those with a history of substance misuse or mental health disorders may be at an increased risk of high-dose zopiclone misuse.[81] High dose misuse of zopiclone and increasing popularity amongst people who use substances who have been prescribed with zopiclone[82] The symptoms of zopiclone addiction can include depression, dysphoria, hopelessness, slow thoughts, social isolation, worrying, sexual anhedonia, and nervousness.[83]

Zopiclone and other sedative hypnotic drugs are detected frequently in cases of people suspected of driving under the influence of drugs. Other sedating drugs, including benzodiazepines and zolpidem, are also found in high numbers of suspected drugged drivers. Many drivers have blood levels far exceeding the therapeutic dose range and often in combination with alcohol, illegal, or addictive prescription drugs, suggesting a high degree of potential for non-medical use of benzodiazepines, zolpidem, and zopiclone.[84] [85] Zopiclone, which at prescribed doses causes moderate impairment the next day, has been estimated to increase the risk of vehicle accidents by 50%, causing an increase of 503 excess accidents per 100,000 persons. Zaleplon or other nonimpairing sleep aids were recommended be used instead of zopiclone to reduce traffic accidents.[86] Zopiclone, as with other hypnotic drugs, is sometimes used to carry out criminal acts such as sexual assaults.[87]

Zopiclone has crosstolerance with barbiturates and is able to suppress barbiturate withdrawal symptoms. It is frequently self-administered intravenously in studies on monkeys, suggesting a high risk of addictive potential.[88]

Zopiclone is in the top ten medications obtained using a false prescription in France.

External links

Notes and References

  1. Web site: Anvisa . Brazilian Health Regulatory Agency . 2023-03-31 . RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial . Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control. live . https://web.archive.org/web/20230803143925/https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 . 2023-08-03 . 2023-08-16 . . pt-BR . 2023-04-04.
  2. Web site: Assessment of Zopiclone. World Health Organization. Essential Medicines and Health Products . World Health Organization. 2006. 5 December 2015. 9 (Section 5. Pharmacokinetics).
  3. Web site: Zopiclone consumer information from . Drugs.com . 2013-06-06.
  4. Current as of 8 June 2023
  5. 2744064 . 1989 . Van Der Kleijn E . Effects of zopiclone and temazepam on sleep, behaviour and mood during the day . 36 . 3 . 247–251 . 0031-6970 . European Journal of Clinical Pharmacology . 10.1007/BF00558155 .
  6. What's wrong with prescribing hypnotics? . Drug and Therapeutics Bulletin . 42 . 12 . 89–93 . December 2004 . 15587763 . 10.1136/dtb.2004.421289 . 40188442 .
  7. Touitou Y . [Sleep disorders and hypnotic agents: medical, social and economical impact] . fr . Annales Pharmaceutiques Françaises . 65 . 4 . 230–238 . July 2007 . 17652991 . 10.1016/s0003-4509(07)90041-3 .
  8. Liira J, Verbeek JH, Costa G, Driscoll TR, Sallinen M, Isotalo LK, Ruotsalainen JH . Pharmacological interventions for sleepiness and sleep disturbances caused by shift work . The Cochrane Database of Systematic Reviews . 2014 . 8 . CD009776 . August 2014 . 25113164 . 10.1002/14651858.CD009776.pub2 . 10025070 .
  9. Cognitive therapy superior to zopiclone for insomnia . The Journal of Family Practice . 55 . 10 . 845 . October 2006 . 17089469 .
  10. Baillargeon L, Landreville P, Verreault R, Beauchemin JP, Grégoire JP, Morin CM . Discontinuation of benzodiazepines among older insomniac adults treated with cognitive-behavioural therapy combined with gradual tapering: a randomized trial . CMAJ . 169 . 10 . 1015–1020 . November 2003 . 14609970 . 236226 .
  11. Sivertsen B, Omvik S, Pallesen S, Bjorvatn B, Havik OE, Kvale G, Nielsen GH, Nordhus IH . Cognitive behavioral therapy vs zopiclone for treatment of chronic primary insomnia in older adults: a randomized controlled trial . JAMA . 295 . 24 . 2851–2858 . June 2006 . 16804151 . 10.1001/jama.295.24.2851 .
  12. Morgan K, Dixon S, Mathers N, Thompson J, Tomeny M . Psychological treatment for insomnia in the regulation of long-term hypnotic drug use . Health Technology Assessment . 8 . 8 . iii–iv, 1–68 . February 2004 . 14960254 . 10.3310/hta8080 . free .
  13. Mets MA, Volkerts ER, Olivier B, Verster JC . Effect of hypnotic drugs on body balance and standing steadiness . Sleep Medicine Reviews . 14 . 4 . 259–267 . August 2010 . 20171127 . 10.1016/j.smrv.2009.10.008 .
  14. Tada K, Sato Y, Sakai T, Ueda N, Kasamo K, Kojima T . Effects of zopiclone, triazolam, and nitrazepam on standing steadiness . Neuropsychobiology . 29 . 1 . 17–22 . 1994 . 8127419 . 10.1159/000119057 .
  15. Allain H, Bentué-Ferrer D, Tarral A, Gandon JM . Effects on postural oscillation and memory functions of a single dose of zolpidem 5 mg, zopiclone 3.75 mg and lormetazepam 1 mg in elderly healthy subjects. A randomized, cross-over, double-blind study versus placebo . European Journal of Clinical Pharmacology . 59 . 3 . 179–188 . July 2003 . 12756510 . 10.1007/s00228-003-0591-5 . 13440208 .
  16. Antai-Otong D . The art of prescribing. Risks and benefits of non-benzodiazepine receptor agonists in the treatment of acute primary insomnia in older adults . Perspectives in Psychiatric Care . 42 . 3 . 196–200 . August 2006 . 16916422 . 10.1111/j.1744-6163.2006.00070.x .
  17. Bain KT . Management of chronic insomnia in elderly persons . The American Journal of Geriatric Pharmacotherapy . 4 . 2 . 168–192 . June 2006 . 16860264 . 10.1016/j.amjopharm.2006.06.006 .
  18. Parker G, Roberts CJ . Plasma concentrations and central nervous system effects of the new hypnotic agent zopiclone in patients with chronic liver disease . British Journal of Clinical Pharmacology . 16 . 3 . 259–265 . September 1983 . 6626417 . 1428012 . 10.1111/j.1365-2125.1983.tb02159.x .
  19. Kripke DF . Mortality Risk of Hypnotics: Strengths and Limits of Evidence . Drug Safety . 39 . 2 . 93–107 . February 2016 . 26563222 . 10.1007/s40264-015-0362-0 . 7946506 . free .
  20. Staner L, Ertlé S, Boeijinga P, Rinaudo G, Arnal MA, Muzet A, Luthringer R . Next-day residual effects of hypnotics in DSM-IV primary insomnia: a driving simulator study with simultaneous electroencephalogram monitoring . Psychopharmacology . 181 . 4 . 790–798 . October 2005 . 16025317 . 10.1007/s00213-005-0082-8 . 26351598 .
  21. Barbone F, McMahon AD, Davey PG, Morris AD, Reid IC, McDevitt DG, MacDonald TM . Association of road-traffic accidents with benzodiazepine use . Lancet . 352 . 9137 . 1331–1336 . October 1998 . 9802269 . 10.1016/S0140-6736(98)04087-2 . 40825194 .
  22. Yasui M, Kato A, Kanemasa T, Murata S, Nishitomi K, Koike K, Tai N, Shinohara S, Tokomura M, Horiuchi M, Abe K . [Pharmacological profiles of benzodiazepinergic hypnotics and correlations with receptor subtypes] . Nihon Shinkei Seishin Yakurigaku Zasshi = Japanese Journal of Psychopharmacology . 25 . 3 . 143–151 . June 2005 . 16045197 .
  23. Rettig HC, de Haan P, Zuurmond WW, von Leeuwen L . Effects of hypnotics on sleep and psychomotor performance. A double-blind randomised study of lormetazepam, midazolam and zopiclone . Anaesthesia . 45 . 12 . 1079–1082 . December 1990 . 2278337 . 10.1111/j.1365-2044.1990.tb14896.x . 36841164 . free .
  24. Lader M, Denney SC . A double-blind study to establish the residual effects of zopiclone on performance in healthy volunteers . International Pharmacopsychiatry . 17 . Suppl 2 . 98–108 . 1982 . 7188379 .
  25. Billiard M, Besset A, de Lustrac C, Brissaud L . Dose-response effects of zopiclone on night sleep and on nighttime and daytime functioning . Sleep . 10 . Suppl 1 . 27–34 . 1987 . 3326113 . 10.1093/sleep/10.suppl_1.27 . free .
  26. Paul MA, Gray G, Kenny G, Pigeau RA . Impact of melatonin, zaleplon, zopiclone, and temazepam on psychomotor performance . Aviation, Space, and Environmental Medicine . 74 . 12 . 1263–1270 . December 2003 . 14692469 . Aerospace Medical Association .
  27. Trachsel L, Dijk DJ, Brunner DP, Klene C, Borbély AA . Effect of zopiclone and midazolam on sleep and EEG spectra in a phase-advanced sleep schedule . Neuropsychopharmacology . 3 . 1 . 11–18 . February 1990 . 2306331 .
  28. Mann K, Bauer H, Hiemke C, Röschke J, Wetzel H, Benkert O . Acute, subchronic and discontinuation effects of zopiclone on sleep EEG and nocturnal melatonin secretion . Eur Neuropsychopharmacol . 6 . 3 . 163–168 . August 1996 . 8880074 . 10.1016/0924-977X(96)00014-4. 25259646 .
  29. Wright NA, Belyavin A, Borland RG, Nicholson AN . Modulation of delta activity by hypnotics in middle-aged subjects: studies with a benzodiazepine (flurazepam) and a cyclopyrrolone (zopiclone) . Sleep . 9 . 2 . 348–352 . June 1986 . 3505734 . 10.1093/sleep/9.2.348. free .
  30. Kim YD, Zhuang HY, Tsutsumi M, Okabe A, Kurachi M, Kamikawa Y . Comparison of the effect of zopiclone and brotizolam on sleep EEG by quantitative evaluation in healthy young women . Sleep . 16 . 7 . 655–661 . October 1993 . 8290860 . 10.1093/sleep/16.7.655. free .
  31. Kanno O, Watanabe H, Kazamatsuri H . Effects of zopiclone, flunitrazepam, triazolam and levomepromazine on the transient change in sleep-wake schedule: polygraphic study, and the evaluation of sleep and daytime condition . Prog. Neuropsychopharmacol. Biol. Psychiatry . 17 . 2 . 229–239 . March 1993 . 8430216 . 10.1016/0278-5846(93)90044-S. 54285586 .
  32. Noguchi H, Kitazumi K, Mori M, Shiba T . Electroencephalographic properties of zaleplon, a non-benzodiazepine sedative/hypnotic, in rats . Journal of Pharmacological Sciences . 94 . 3 . 246–251 . March 2004 . 15037809 . 10.1254/jphs.94.246 . free .
  33. Mannaert E, Tytgat J, Daenens P . Detection and quantification of the hypnotic zopiclone, connected with an uncommon case of drowning . Forensic Science International . 83 . 1 . 67–72 . November 1996 . 8939015 . 10.1016/0379-0738(96)02018-X .
  34. Buckley NA, Dawson AH, Whyte IM, McManus P, Ferguson N.Correlations between prescriptions and drugs taken in self-poisoning: Implications for prescribers and drug regulation.Med J Aust (in press)
  35. Buckley NA, Dawson AH, Whyte IM, O'Connell DL . Relative toxicity of benzodiazepines in overdose . BMJ . 310 . 6974 . 219–221 . January 1995 . 7866122 . 2548618 . 10.1136/bmj.310.6974.219 .
  36. Meatherall RC . Zopiclone fatality in a hospitalized patient . Journal of Forensic Sciences . 42 . 2 . 340–343 . March 1997 . 9068198 . 10.1520/JFS14125J .
  37. Van Bocxlaer J, Meyer E, Clauwaert K, Lambert W, Piette M, De Leenheer A . Analysis of zopiclone (Imovane) in postmortem specimens by GC-MS and HPLC with diode-array detection . Journal of Analytical Toxicology . 20 . 1 . 52–54 . 1996 . 8837952 . 10.1093/jat/20.1.52 . free .
  38. Yamazaki M, Terada M, Mitsukuni Y, Yoshimura M . [An autopsy case of poisoning by neuropsychopharmaceuticals including zopiclone] . ja . Nihon Hoigaku Zasshi = the Japanese Journal of Legal Medicine . 52 . 4 . 245–252 . August 1998 . 9893443 .
  39. Boniface PJ, Russell SG . Two cases of fatal zopiclone overdose . Journal of Analytical Toxicology . 20 . 2 . 131–133 . 1996 . 8868406 . 10.1093/jat/20.2.131 .
  40. Cienki JJ, Burkhart KK, Donovan JW . Zopiclone overdose responsive to flumazenil . Clinical Toxicology . 43 . 5 . 385–386 . 2005 . 16235515 . 10.1081/clt-200058944 . 41701825 . free .
  41. Pounder DJ, Davies JI . Zopiclone poisoning: tissue distribution and potential for postmortem diffusion . Forensic Science International . 65 . 3 . 177–183 . May 1994 . 8039775 . 10.1016/0379-0738(94)90273-9 .
  42. Regouby Y, Delomez G, Tisserant A . [First-degree heart block caused by voluntary zopiclone poisoning] . fr . Therapie . 45 . 2 . 162 . 1990 . 2353332 .
  43. Regouby Y, Delomez G, Tisserant A . [Auriculo-ventricular block during voluntary poisoning with zopiclone] . fr . Therapie . 44 . 5 . 379–380 . 1989 . 2814922 .
  44. Book: Medical Toxicology. Dart RC . 2003. 978-0-7817-2845-4. 889. Lippincott Williams & Wilkins .
  45. Carlsten A, Waern M, Holmgren P, Allebeck P . The role of benzodiazepines in elderly suicides . Scandinavian Journal of Public Health . 31 . 3 . 224–228 . 2003 . 12850977 . 10.1080/14034940210167966 . 24102880 .
  46. Harry P . [Acute poisoning by new psychotropic drugs] . La Revue du Praticien . 47 . 7 . 731–735 . April 1997 . 9183949 .
  47. Bramness JG, Arnestad M, Karinen R, Hilberg T . Fatal overdose of zopiclone in an elderly woman with bronchogenic carcinoma . Journal of Forensic Sciences . 46 . 5 . 1247–1249 . September 2001 . 11569575 . 10.1520/JFS15131J .
  48. Caille G, du Souich P, Spenard J, Lacasse Y, Vezina M . Pharmacokinetic and clinical parameters of zopiclone and trimipramine when administered simultaneously to volunteers . Biopharmaceutics & Drug Disposition . 5 . 2 . 117–125 . April 1984 . 6743780 . 10.1002/bdd.2510050205 .
  49. Mattila ME, Mattila MJ, Nuotto E . Caffeine moderately antagonizes the effects of triazolam and zopiclone on the psychomotor performance of healthy subjects . Pharmacology & Toxicology . 70 . 4 . 286–289 . April 1992 . 1351673 . 10.1111/j.1600-0773.1992.tb00473.x .
  50. Koski A, Ojanperä I, Vuori E . Interaction of alcohol and drugs in fatal poisonings . Human & Experimental Toxicology . 22 . 5 . 281–287 . May 2003 . 12774892 . 10.1191/0960327103ht324oa . 37777007 .
  51. Kuitunen T, Mattila MJ, Seppala T . Actions and interactions of hypnotics on human performance: single doses of zopiclone, triazolam and alcohol . International Clinical Psychopharmacology . 5 . Suppl 2 . 115–130 . April 1990 . 2201724 .
  52. Aranko K, Luurila H, Backman JT, Neuvonen PJ, Olkkola KT . The effect of erythromycin on the pharmacokinetics and pharmacodynamics of zopiclone . British Journal of Clinical Pharmacology . 38 . 4 . 363–367 . October 1994 . 7833227 . 1364781 . 10.1111/j.1365-2125.1994.tb04367.x .
  53. Jalava KM, Olkkola KT, Neuvonen PJ . Effect of itraconazole on the pharmacokinetics and pharmacodynamics of zopiclone . European Journal of Clinical Pharmacology . 51 . 3–4 . 331–334 . 1996 . 9010708 . 10.1007/s002280050207 . 20916689 .
  54. Villikka K, Kivistö KT, Lamberg TS, Kantola T, Neuvonen PJ . Concentrations and effects of zopiclone are greatly reduced by rifampicin . British Journal of Clinical Pharmacology . 43 . 5 . 471–474 . May 1997 . 9159561 . 2042775 . 10.1046/j.1365-2125.1997.00579.x .
  55. Becquemont L, Mouajjah S, Escaffre O, Beaune P, Funck-Brentano C, Jaillon P . Cytochrome P-450 3A4 and 2C8 are involved in zopiclone metabolism . Drug Metabolism and Disposition . 27 . 9 . 1068–1073 . September 1999 . 10460808 . 2008-12-16 . 2005-04-17 . https://web.archive.org/web/20050417094458/http://dmd.aspetjournals.org/cgi/content/full/27/9/1068 . dead .
  56. Alderman CP, Gebauer MG, Gilbert AL, Condon JT . Possible interaction of zopiclone and nefazodone . The Annals of Pharmacotherapy . 35 . 11 . 1378–1380 . November 2001 . 11724087 . 10.1345/aph.1A074 . 38894701 .
  57. Röschke J, Mann K, Aldenhoff JB, Benkert O . Functional properties of the brain during sleep under subchronic zopiclone administration in man . European Neuropsychopharmacology . 4 . 1 . 21–30 . March 1994 . 8204993 . 10.1016/0924-977X(94)90311-5 . 40503805 .
  58. Petroski RE, Pomeroy JE, Das R, Bowman H, Yang W, Chen AP, Foster AC . Indiplon is a high-affinity positive allosteric modulator with selectivity for alpha1 subunit-containing GABAA receptors . The Journal of Pharmacology and Experimental Therapeutics . 317 . 1 . 369–377 . April 2006 . 16399882 . 10.1124/jpet.105.096701 . 46510829 .
  59. Atack JR . Anxioselective compounds acting at the GABA(A) receptor benzodiazepine binding site . Current Drug Targets. CNS and Neurological Disorders . 2 . 4 . 213–232 . August 2003 . 12871032 . 10.2174/1568007033482841 .
  60. 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 . International Journal of Clinical Pharmacology, Therapy, and Toxicology . 23 . 3 . 121–128 . March 1985 . 2581904 .
  61. 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 . International Journal of Clinical Pharmacology, Therapy, and Toxicology . 23 . 4 . 204–210 . April 1985 . 2860074 .
  62. Dündar 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 . Human Psychopharmacology . 19 . 5 . 305–322 . July 2004 . 15252823 . 10.1002/hup.594 . 10888200 .
  63. Blanchard JC, Julou L . Suriclone: a new cyclopyrrolone derivative recognizing receptors labeled by benzodiazepines in rat hippocampus and cerebellum . Journal of Neurochemistry . 40 . 3 . 601–607 . March 1983 . 6298365 . 10.1111/j.1471-4159.1983.tb08023.x . 35732735 .
  64. Skerritt JH, Johnston GA . Enhancement of GABA binding by benzodiazepines and related anxiolytics . European Journal of Pharmacology . 89 . 3–4 . 193–198 . May 1983 . 6135616 . 10.1016/0014-2999(83)90494-6 .
  65. De Deyn PP, Macdonald RL . Effects of non-sedative anxiolytic drugs on responses to GABA and on diazepam-induced enhancement of these responses on mouse neurones in cell culture . British Journal of Pharmacology . 95 . 1 . 109–120 . September 1988 . 2905900 . 1854132 . 10.1111/j.1476-5381.1988.tb16554.x .
  66. Julou L, Bardone MC, Blanchard JC, Garret C, Stutzmann JM . Pharmacological studies on zopiclone . Pharmacology . 27 . Suppl 2 . 46–58 . 1983 . 6142468 . 10.1159/000137911 .
  67. Blanchard JC, Boireau A, Julou L . Brain receptors and zopiclone . Pharmacology . 27 . Suppl 2 . 59–69 . 1983 . 6322210 . 10.1159/000137912 .
  68. Gaillot J, Heusse D, Hougton GW, Marc Aurele J, Dreyfus JF . Pharmacokinetics and metabolism of zopiclone . International Pharmacopsychiatry . 17 . Suppl 2 . 76–91 . 1982 . 7188377 .
  69. Viron B, De Meyer M, Le Liboux A, Frydman A, Maillard F, Mignon F, Gaillot J . Steady state pharmacokinetics of zopiclone during multiple oral dosing (7.5 mg nocte) in patients with severe chronic renal failure . International Clinical Psychopharmacology . 5 . Suppl 2 . 95–104 . April 1990 . 2387982 .
  70. Web site: Zopiclone . pubchem.ncbi.nlm.nih.gov . U.S. National Library of Medicine . 11 June 2018 . en.
  71. Kratzsch C, Tenberken O, Peters FT, Weber AA, Kraemer T, Maurer HH . Screening, library-assisted identification and validated quantification of 23 benzodiazepines, flumazenil, zaleplone, zolpidem and zopiclone in plasma by liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization . Journal of Mass Spectrometry . 39 . 8 . 856–72 . August 2004 . 15329838 . 10.1002/jms.599 . 2004JMSp...39..856K .
  72. Gustavsen I, Al-Sammurraie M, Mørland J, Bramness JG . Impairment related to blood drug concentrations of zopiclone and zolpidem compared to alcohol in apprehended drivers . Accident Analysis and Prevention . 41 . 3 . 462–6 . May 2009 . 19393793 . 10.1016/j.aap.2009.01.011 .
  73. Book: Baselt R . Disposition of Toxic Drugs and Chemicals in Man . 8th . Biomedical Publications . Foster City, CA . 2008 . 1677–1679 .
  74. Holbrook AM, Crowther R, Lotter A, Cheng C, King D . Meta-analysis of benzodiazepine use in the treatment of insomnia . CMAJ . 162 . 2 . 225–233 . January 2000 . 10674059 . 1232276 .
  75. Blaschke G, Hempel G, Müller WE . Preparative and analytical separation of the zopiclone enantiomers and determination of their affinity to the benzodiazepine receptor binding site . Chirality . 5 . 6 . 419–421 . 1993 . 8398600 . 10.1002/chir.530050605 .
  76. Fernandez C, Maradeix V, Gimenez F, Thuillier A, Farinotti R . Pharmacokinetics of zopiclone and its enantiomers in Caucasian young healthy volunteers . Drug Metabolism and Disposition . 21 . 6 . 1125–1128 . November 1993 . 7905394 .
  77. Cimolai N . Zopiclone: is it a pharmacologic agent for abuse? . Canadian Family Physician . 53 . 12 . 2124–2129 . December 2007 . 18077750 . 2231551 .
  78. Griffiths RR, Johnson MW . Relative abuse liability of hypnotic drugs: a conceptual framework and algorithm for differentiating among compounds . The Journal of Clinical Psychiatry . 66 . Suppl 9 . 31–41 . 2005 . 16336040 .
  79. Hoffmann F, Pfannkuche M, Glaeske G . [High usage of zolpidem and zopiclone. Cross-sectional study using claims data] . de . Der Nervenarzt . 79 . 1 . 67–72 . January 2008 . 17457554 . 10.1007/s00115-007-2280-6 . 31103719 .
  80. Bramness JG, Olsen H . [Adverse effects of zopiclone] . no . Tidsskrift for den Norske Laegeforening . 118 . 13 . 2029–2032 . May 1998 . 9656789 .
  81. Ströhle A, Antonijevic IA, Steiger A, Sonntag A . [Dependency of non-benzodiazepine hypnotics. Two case reports] . de . Der Nervenarzt . 70 . 1 . 72–75 . January 1999 . 10087521 . 10.1007/s001150050403 . 42630879 .
  82. Sikdar S . Physical dependence on zopiclone. Prescribing this drug to addicts may give rise to iatrogenic drug misuse . BMJ . 317 . 7151 . 146 . July 1998 . 9657802 . 1113504 . 10.1136/bmj.317.7151.146 .
  83. Kuntze MF, Bullinger AH, Mueller-Spahn F . Excessive use of zopiclone: a case report . Swiss Medical Weekly . 132 . 35–36 . 523 . September 2002 . 10.4414/smw.2002.10074 . 12506335 . 33400840 . 2008-12-18 . 2016-03-03 . https://web.archive.org/web/20160303165243/http://www.smw.ch/docs/pdf200x/2002/35/smw-10074.pdf . dead .
  84. Jones AW, Holmgren A, Kugelberg FC . Concentrations of scheduled prescription drugs in blood of impaired drivers: considerations for interpreting the results . Therapeutic Drug Monitoring . 29 . 2 . 248–260 . April 2007 . 17417081 . 10.1097/FTD.0b013e31803d3c04 . 25511804 .
  85. Bramness JG, Skurtveit S, Mørland J . [Detection of zopiclone in many drivers--a sign of misuse or abuse] . no . Tidsskrift for den Norske Laegeforening . 119 . 19 . 2820–2821 . August 1999 . 10494203 .
  86. Menzin J, Lang KM, Levy P, Levy E . A general model of the effects of sleep medications on the risk and cost of motor vehicle accidents and its application to France . PharmacoEconomics . 19 . 1 . 69–78 . January 2001 . 11252547 . 10.2165/00019053-200119010-00005 . 45013069 .
  87. Kintz P, Villain M, Ludes B . Testing for the undetectable in drug-facilitated sexual assault using hair analyzed by tandem mass spectrometry as evidence . Therapeutic Drug Monitoring . 26 . 2 . 211–214 . April 2004 . 15228167 . 10.1097/00007691-200404000-00022 . 46445345 .
  88. Yanagita T . Dependence potential of zopiclone studied in monkeys . International Pharmacopsychiatry . 17 . 2 . 216–227 . 1982 . 6892368 .