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Trade names | Imovane, Zimovane, Dopareel, others |
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Routes of administration | Oral tablets, 3.75 mg or 7.5mg ( UK ), 5 mg, 7.5 mg, or 10 mg ( JP ) |
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Pharmacokinetic data | |
Bioavailability | 75–80% [2] |
Protein binding | 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%) |
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ECHA InfoCard | 100.051.018 |
Chemical and physical data | |
Formula | C17H17ClN6O3 |
Molar mass | 388.81 g·mol−1 |
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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. [ citation needed ]
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. [ citation needed ]
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]
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]
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]
Patients with liver disease eliminate zopiclone much more slowly than normal patients and in addition experience exaggerated pharmacological effects of the drug. [18]
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". [20]
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. [21] Patients who drive motor vehicles should not take zopiclone as there is a significantly increased risk of accidents in zopiclone users. [22] Zopiclone induces impairment of psychomotor function. [23] [24] Driving or operating machinery should be avoided after taking zopiclone as effects can carry over to the next day, including impaired hand-eye coordination. [25] [26]
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, 6.25, and 5.25 hours; for LRT 3.25, >6.25, and 4.25 hours; for SST 2.25, >6.25, and 4.25 hours; and for MT 2.25, 4.25, and 3.25 hours. The study did not consider the effectiveness of the drugs on sleep. [27]
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. [28] [29] Zopiclone reduces both delta waves and the number of high-amplitude delta waves whilst increasing low-amplitude waves. [30] Zopiclone reduces the total amount of time spent in REM sleep as well as delaying its onset. [31] [32] 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. [33]
Zopiclone is sometimes used as a method of suicide. [34] It has a similar fatality index to that of benzodiazepine drugs, apart from temazepam, which is particularly toxic in overdose. [35] [36] Deaths have occurred from zopiclone overdose, alone or in combination with other drugs. [37] [38] [39] Overdose of zopiclone may present with excessive sedation and depressed respiratory function that may progress to coma and possibly death. [40] 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. [41] [42] Serious effects on the heart may also occur from a zopiclone overdose [43] [44] when combined with piperazine. [45]
Death certificates show the number of zopiclone-related deaths is on the rise. [46] 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. [47] [48]
Zopiclone also interacts with trimipramine and caffeine. [49] [50]
Alcohol has an additive effect when combined with zopiclone, enhancing the adverse effects including the overdose potential of zopiclone significantly. [51] [52] 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. [53] [54] 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. [55] Ketoconazole and sulfaphenazole interfere with the metabolism of zopiclone. [56] Nefazodone impairs the metabolism of zopiclone leading to increased zopiclone levels and marked next-day sedation. [57]
The therapeutic pharmacological properties of zopiclone include hypnotic, anxiolytic, anticonvulsant, and myorelaxant properties. [58] 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, [59] 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. [60] The mechanism of action of zopiclone is similar to benzodiazepines, with similar effects on locomotor activity and on dopamine and serotonin turnover. [61] [62] 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. [63] 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. [64] [65] [66] In addition to zopiclone's benzodiazepine pharmacological properties, it also has some barbiturate-like properties. [67] [68]
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). [2]
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. [69] 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. [70] Sex and race have not been found to interact with pharmacokinetics of zopiclone. [2]
The melting point of zopiclone is 178 °C. [71] Zopiclone's solubility in water, at room temperature (25 °C) are 0.151 mg/mL. [71] The logP value of zopiclone is 0.8. [71]
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. [72] [73] [74]
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. [75] 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. [76] [77] 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[ citation needed ]. The two agents have not yet[ when? ] 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.).
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. [78] 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. [79] [80] Zopiclone may be more addictive than benzodiazepines. [81] Those with a history of substance misuse or mental health disorders may be at an increased risk of high-dose zopiclone misuse. [82] High dose misuse of zopiclone and increasing popularity amongst people who use substances who have been prescribed with zopiclone [83] [ clarification needed ] The symptoms of zopiclone addiction can include depression, dysphoria, hopelessness, slow thoughts, social isolation, worrying, sexual anhedonia, and nervousness. [84]
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. [85] [86] 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. [87] Zopiclone, as with other hypnotic drugs, is sometimes used to carry out criminal acts such as sexual assaults. [88]
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. [89]
Zopiclone is in the top ten medications obtained using a false prescription in France. [2]
Flunitrazepam, sold under the brand name Rohypnol among others, is a benzodiazepine used to treat severe insomnia and assist with anesthesia. As with other hypnotics, flunitrazepam has been advised to be prescribed only for short-term use or by those with chronic insomnia on an occasional basis.
Hypnotic, or soporific drugs, commonly known as sleeping pills, are a class of psychoactive drugs whose primary function is to induce sleep and to treat insomnia (sleeplessness).
Temazepam, sold under the brand name Restoril among others, is a medication of the benzodiazepine class which is generally used to treat severe or debilitating insomnia. It is taken by mouth. Temazepam is rapidly absorbed, and significant hypnotic effects begin in less than 30 minutes and can last for up to eight hours. Prescriptions for hypnotics such as temazepam have seen a dramatic decrease since 2010, while anxiolytics such as alprazolam, clonazepam, and lorazepam have increased or remained stable. Temazepam and similar hypnotics, such as triazolam (Halcion) are generally reserved for severe and debilitating insomnia. They have largely been replaced by z-drugs and atypical antidepressants as first line treatment for insomnia.
Zolpidem, sold under the brand name Ambien among others, is a medication primarily used for the short-term treatment of sleeping problems. Guidelines recommend that it be used only after cognitive behavioral therapy for insomnia and after behavioral changes, such as sleep hygiene, have been tried. It decreases the time to sleep onset by about fifteen minutes and at larger doses helps people stay asleep longer. It is taken by mouth and is available in conventional tablets, sublingual tablets, or oral spray.
Triazolam, sold under the brand name Halcion among others, is a central nervous system (CNS) depressant tranquilizer of the triazolobenzodiazepine (TBZD) class, which are benzodiazepine (BZD) derivatives. It possesses pharmacological properties similar to those of other benzodiazepines, but it is generally only used as a sedative to treat severe insomnia. In addition to the hypnotic properties, triazolam's amnesic, anxiolytic, sedative, anticonvulsant, and muscle relaxant properties are pronounced as well.
Nitrazepam, sold under the brand name Mogadon among others, is a hypnotic drug of the benzodiazepine class used for short-term relief from severe, disabling anxiety and insomnia. It also has sedative (calming) properties, as well as amnestic, anticonvulsant, and skeletal muscle relaxant effects.
Flurazepam is a drug which is a benzodiazepine derivative. It possesses anxiolytic, anticonvulsant, hypnotic, sedative and skeletal muscle relaxant properties. It produces a metabolite with a long half-life, which may stay in the bloodstream for days. Flurazepam was patented in 1968 and came into medical use the same year. Flurazepam, developed by Roche Pharmaceuticals, was one of the first benzodiazepine hypnotic medications to be marketed.
Eszopiclone, sold under the brand name Lunesta among others, is a medication used in the treatment of insomnia. Evidence supports slight to moderate benefit up to six months. It is taken by mouth.
Zaleplon, sold under the brand name Sonata among others, is a sedative and hypnotic which is used to treat insomnia. It is a nonbenzodiazepine or Z-drug of the pyrazolopyrimidine class. It was developed by King Pharmaceuticals and approved for medical use in the United States in 1999.
Nonbenzodiazepines, sometimes referred to colloquially as Z-drugs, are a class of psychoactive, depressant, sedative, hypnotic, anxiolytic drugs that are benzodiazepine-like in uses, such as for treating insomnia and anxiety.
Quazepam, sold under the brand name Doral among others, is a relatively long-acting benzodiazepine derivative drug developed by the Schering Corporation in the 1970s. Quazepam is used for the treatment of insomnia, including sleep induction and sleep maintenance. Quazepam induces impairment of motor function and has relatively selective hypnotic and anticonvulsant properties with considerably less overdose potential than other benzodiazepines. Quazepam is an effective hypnotic which induces and maintains sleep without disruption of the sleep architecture.
Estazolam, sold under the brand name Prosom among others, is a tranquilizer medication of the triazolobenzodiazepine (TBZD) class, which are benzodiazepines (BZDs) fused with a triazole ring. It possesses anxiolytic, anticonvulsant, hypnotic, sedative and skeletal muscle relaxant properties. Estazolam is an intermediate-acting oral benzodiazepine. It is used for short-term treatment of insomnia.
Alpidem, sold under the brand name Ananxyl, is a nonbenzodiazepine anxiolytic medication which was briefly used to treat anxiety disorders but is no longer marketed. It was previously marketed in France, but was discontinued due to liver toxicity. Alpidem is taken by mouth.
Loprazolam (triazulenone) marketed under many brand names is a benzodiazepine medication. It possesses anxiolytic, anticonvulsant, hypnotic, sedative and skeletal muscle relaxant properties. It is licensed and marketed for the short-term treatment of moderately-severe insomnia.
Lormetazepam, sold under the brand name Noctamid among others, is a drug which is a short to intermediate acting 3-hydroxy benzodiazepine derivative and temazepam analogue. It possesses hypnotic, anxiolytic, anticonvulsant, sedative, and skeletal muscle relaxant properties.
Brotizolam is a sedative-hypnotic thienotriazolodiazepine drug which is a benzodiazepine analog. It possesses anxiolytic, anticonvulsant, hypnotic, sedative and skeletal muscle relaxant properties, and is considered to be similar in effect to other short-acting hypnotic benzodiazepines such as triazolam or midazolam. It is used in the short-term treatment of severe insomnia. Brotizolam is a highly potent and short-acting hypnotic, with a typical dose ranging from 0.125 to 0.25 milligrams, which is rapidly eliminated with an average half-life of 4.4 hours.
Fosazepam is a drug which belonging to the benzodiazepine class of drugs, which are primarily anti-anxiety and sedative-hypnotic agents. It is a water soluble derivative of diazepam which has been substituted with a dimethylphosphoryl group to improve solubility in water. At equipotent doses, it possesses sedative and anxiolytic properties that are qualitatively and quantitatively similar to the effects of diazepam, with equal sedative-hypnotic, anti-convulsive, and muscle relaxant effects. In comparison to an equipotent dose of nitrazepam ,, its effects tended to be of noticeably milder magnitude.
Suvorexant, sold under the brand name Belsomra, is an orexin antagonist medication which is used in the treatment of insomnia. It is indicated specifically for the treatment of insomnia characterized by difficulties with sleep onset and/or maintenance in adults. Suvorexant helps with falling asleep faster, sleeping longer, being awake less in the middle of the night, and having better quality of sleep. Its effectiveness is modest, and is similar to that of other orexin antagonists, but is lower than that of benzodiazepines and Z-drugs. Suvorexant is taken by mouth.
Daridorexant, sold under the brand name Quviviq, is an orexin antagonist medication which is used for the treatment of insomnia. Daridorexant is taken by mouth.
Somnifacient, also known as sedatives or sleeping pills, is a class of medications that induces sleep. It is mainly used for treatment of insomnia. Examples of somnifacients include benzodiazepines, barbiturates and antihistamines.
This guidance will be reviewed if there is new evidence.Current as of 8 June 2023