Zopiclone
Zopiclone was developed and first introduced in 1986 by Rhône-Poulenc S.A., now part of Sanofi-Aventis, 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. 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
Zopiclone is sometimes used as a method of suicide. It has a similar fatality index to that of benzodiazepine drugs, apart from temazepam, which is particularly toxic in overdose. Deaths have occurred from zopiclone overdose, alone or in combination with other drugs. Overdose of zopiclone may present with excessive sedation and depressed respiratory function that may progress to coma and possibly death. 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 benzodiazepine receptor antagonist flumazenil, which displaces zopiclone from its binding site on the benzodiazepine receptor, thereby rapidly reversing its effects. Serious effects on the heart may also occur from a zopiclone overdose when combined with piperazine.