The sleep medicine zopiclone (eszopiclone) is commonly used in most Western countries. The focus on legislation for possible traffic-impairing nonalcohol drugs have caused a need for comparing traffic relevant behavior after intake of commonly used psychoactive drugs to blood alcohol concentrations (BACs). We aimed to compare psychomotor effects at 3 levels of behavior at different blood zopiclone concentrations to effects seen at different BACs.
We performed a randomized double-blinded trial on 16 healthy volunteers who received either 10 or 5 mg zopiclone, 50 g ethanol or placebo in a crossover design. The volunteers performed computerized tests at baseline, 1, 3.5, and 6.5 hours after intake, accompanied by blood sampling.
Impairment was found at all 3 behavior levels. For zopiclone, impairment was most pronounced at behavior level 1 (automotive behavior); a mean blood zopiclone concentration at 39 μg/L achieved 1 hour after intake of 10 mg zopiclone was accompanied by more impairment than BAC 0.074 %. At behavior levels 2 (control behavior) and 3 (executive planning), the psychomotor impairment accompanying approximately 39 μg/L zopiclone seemed comparable to a BAC of approximately 0.074%. No test components were impaired at 6.5 hours after intake.
From the *Division of Forensic Toxicology and Drug Abuse, Norwegian Institute of Public Health; †the Department of Clinical Pharmacology, Oslo University Hospital, Rikshospitalet; and ‡the Faculty of Medicine, University of Oslo, Oslo, Norway.
Received October 14, 2010; accepted after revision April 13, 2011.
Reprints: Ingebjørg Gustavsen, MD, Division of Forensic Toxicology and Drug Abuse, Norwegian Institute of Public Health, PO Box 4404 Nydalen, N-0403 Oslo, Norway (e-mail: firstname.lastname@example.org).
This work was funded by internal sources at Norwegian Institute of Public Health, the Division of Forensic Toxicology and Drug Abuse. Grants were received from Ministry of Justice and the Police, and Ministry of Transport and Communications.