Psychomotor performance after intake of zopiclone compared with intake of ethanol: a randomized, controlled, double-blinded trial

J Clin Psychopharmacol. 2011 Aug;31(4):481-8. doi: 10.1097/JCP.0b013e3182214be6.


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.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Azabicyclo Compounds / administration & dosage*
  • Azabicyclo Compounds / blood
  • Cross-Over Studies
  • Double-Blind Method
  • Ethanol / administration & dosage*
  • Ethanol / blood
  • Humans
  • Male
  • Piperazines / administration & dosage*
  • Piperazines / blood
  • Psychomotor Performance / drug effects*
  • Psychomotor Performance / physiology
  • Reaction Time / drug effects*
  • Reaction Time / physiology
  • Young Adult


  • Azabicyclo Compounds
  • Piperazines
  • zopiclone
  • Ethanol