Zopiclone

Zopiclone (brand names Imovane, Zimovane, and Dopareel) is a nonbenzodiazepine hypnotic agent used in the treatment of insomnia. 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 in the central nervous system, via modulating benzodiazepine receptors in the same way that benzodiazepine drugs do. Zopiclone (brand names Imovane, Zimovane, and Dopareel) is a nonbenzodiazepine hypnotic agent used in the treatment of insomnia. 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 in the central nervous system, via modulating benzodiazepine receptors in the same way that benzodiazepine drugs do. As zopiclone is sedating, it is marketed as a sleeping pill. 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, although its active stereoisomer, eszopiclone, is sold under the name Lunesta. Zopiclone is a controlled substance in the United States, Japan, Brazil, and some European countries, and may be illegal to possess without a prescription. However, it is readily available in other countries where it is marketed under the brand name Imovane, and is not a controlled substance in its available 10 mg, 7.5 mg, 5 mg, and 3.75 mg oral tablet formulations. Zopiclone is known colloquially as a 'Z-drug'. Other Z-drugs include zaleplon (Sonata) and zolpidem (Ambien and AmbienCR) and were initially thought to be less addictive or habit-forming 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 on a short-term basis, usually a week or 2 or less. Daily or continuous use of the drug is not usually advised, and caution must be taken when the compound is used in conjunction with antidepressants, sedatives or other drugs affecting the central nervous system. Zopiclone is indicated 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 with prolonged use. One low quality study found that zopiclone is ineffective in improving sleep quality or increasing sleep time in shift workers - more research in this area has been recommended. 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. 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. 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. Patients with liver disease eliminate zopiclone much more slowly than normal patients and in addition experience exaggerated pharmacological effects of the drug. Patients who suffer from muscle weakness due to myasthenia gravis or have poor respiratory reserves due to severe chronic bronchitis, emphysema, or other lung disease, or have sleep apnoea cannot safely take zopiclone, nor can a patient with any untreated abnormality of the thyroid gland.