THE CONSEQUENCES OF ZOPICLONE USE - REBOUND INSOMNIA, DEVELOPMENT OF TOLERANCE, AND ABUSE POTENTIAL

Rebound phenomena, withdrawal symptoms, development of tolerance, the establishment of drug dependence, and abuse potential are well known w ith benzodiazepine hypnotics, particularly when these are administered for periods longer than those normally recommended, it is appropriate to determine whether, or to what extent, similar characteristics are associated with the use of zopiclone, a nonbenzodiazepine hypnotic age nt. As might be expected for a hypnotic drug with a short elimination half-life of about 5 h, zopiclone use has occasionally been associated with reports of rebound effects. These have, however, almost always b een substantially less frequent than those occurring with benzodiazepi nes. There is no evidence of any marked degree of tolerance occurring to zopiclone. Cross-tolerance may occur with benzodiazepines and there are suggestions that this may help patients who are dependent upon be nzodiazepines to withdraw from these drugs, though this aspect of zopi clone use needs further investigation. The development of either physi cal or psychological dependence on zopiclone following its long-term u se, and its abuse by polydrug users, both appear to be rare, in relati on to the extent to which zopiclone is used world-wide. There is littl e evidence of adverse reactions following abrupt withdrawal of zopiclo ne. It is concluded that, in view of its low dependence and abuse pote ntials, as well as its extremely low tendency to lead to rebound effec ts following its withdrawal, zopiclone offers definite advantages over the benzodiazepines.