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Treatment of primary insomnia CMAJ 2000;163(4):389-90 See response from: A. Holbrook, R. Labiris See also: A major problem with the meta-analysis by Anne Holbrook and colleagues of benzodiazepine use in the treatment of insomnia [Review]1 is that benzodiazepines were considered as a single medication; this class of drugs in fact consists of several compounds with marked differences in pharmacokinetics and side-effect profiles. Patients may be prescribed short-, intermediate- or long-acting compounds. Among other side effects, short-acting benzodiazepines cause daytime anxiety, amnesia and rebound insomnia upon withdrawal, whereas long-acting compounds cause residual sleepiness and cognitive impairments. Because the side effects differ so much from one compound to the next, those of benzodiazepines were not found to differ significantly from those of either a placebo or other insomnia treatments in the meta-analysis, which pooled studies investigating different benzodiazepines. They are nevertheless of prime importance for the clinician who has to choose a single hypnotic. These side effects, especially the residual sleepiness and cognitive impairments, considerably limit the clinical use of benzodiazepines. As a result, several controlled studies have concluded that zopiclone should be recommended in ambulant or out-patient populations.2,3 The effects of hypnotics on breathing during sleep should also be considered. There are several indications that benzodiazepines depress respiration during sleep whereas zopiclone does not.4,5,6,7 This is important, especially in patients with chronic obstructive pulmonary disease, sleep apnea syndrome and upper airway resistance and, to a certain extent, in people who snore. Another clinical indication of zopiclone is its usefulness in the treatment of benzodiazepine dependency.8,9,10 Finally, a major advantage of zopiclone is that, unlike most benzodiazepines, it does not modify sleep architecture (most benzodiazepines reduce both slow-wave and REM sleep).6,11 I agree with Anne Holbrook and colleagues that nonpharmacological treatments are the treatment of choice for chronic primary insomnia.1 However, when comparing hypnotics, I believe that zopiclone has several advantages over each benzodiazepine taken separately.
Jacques Montplaisir References
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