Residual effects of zopiclone 7.5 mg on highway driving performance in insomnia patients and healthy controls: a placebo controlled crossover study.
BACKGROUND
Residual effects of hypnotics on driving performance have been mainly determined in studies using a standardized driving test with healthy good sleepers. Responses to effects may differ, however, between insomniacs and healthy volunteers due to the underlying sleep disorder. In addition, a majority of insomniacs uses hypnotics chronically resulting in the development of tolerance to impairing effects. Impaired driving performance in healthy volunteers may then be an overestimation of the actual effects in insomniacs.


OBJECTIVE
The present study aims to compare the residual effects of zopiclone 7.5 mg on on-the-road driving performance of 16 middle-aged insomniacs chronically using hypnotics (chronic users), 16 middle-aged insomniacs not or infrequently using hypnotics (infrequent users), and 16 healthy, age matched, good sleepers (controls).


METHODS
The study was conducted according to a 3 × 2 double-blind, placebo controlled crossover design, with three groups and two treatment conditions. Treatments were single oral doses of zopiclone 7.5 mg and placebo administered at bedtime (2330 hours). Between 10 and 11 h after administration subjects performed a standardized highway driving test.


RESULTS
Zopiclone 7.5 mg significantly impaired on-the-road driving performance in both insomnia groups and healthy controls. The magnitude of impairment was significantly less in the chronic users group as compared with the controls.


CONCLUSIONS
The smaller magnitude of effects suggests that investigating residual effects of hypnotics in healthy volunteers may yield a minor overestimation of the actual effects in insomnia patients.
Division Information and Cognition, Department of Brain, Body and Behavior, Philips Group Innovation-Research, High Tech Campus 34, 5656, AE, Eindhoven, The Netherlands, tim.leufkens@philips.com.
T R M
TR
Leufkens
J G
JG
Ramaekers
A W
AW
de Weerd
W J
WJ
Riedel
A
A
Vermeeren
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D001334:Automobile Driving; D053961:Azabicyclo Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D016022:Case-Control Studies; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology*; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy*
D053961:Azabicyclo Compounds; D006993:Hypnotics and Sedatives; D010879:Piperazines; C515050:zopiclone