Zopiclone

Zopiclone (trade names: Imovane™ and 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. more...

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. Apart from the difference in dosage (eszopiclone dosages are exactly one-half that of equivalent Zopiclone dosages), the two drugs are identical in effect.

Adverse Reactions

The side-effect most commonly seen in clinical trials is taste alteration (bitter, metallic taste).

More Common Reactions:

Gastrointestinal: bitter metallic taste, dry mouth.
Nervous System: drowsiness, headaches, fatigue.

Less Common Reactions:

Gastrointestinal: heartburn, constipation, diarrhoea, nausea, coated tongue, bad breath, anorexia or increased appetite, vomiting, epigastric pains, dyspepsia.
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, euphoria, depression, coordination abnormality, hypotonia, speech disorder, hallucinations (auditory and visual), behavioural disorders, aggression, tremor, rebound insomnia, nightmares.

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