Prior sleep with zolpidem enhances the effect of caffeine or modafinil during 18 hours continuous work.
BACKGROUND
Continuous military operations may disrupt sleep-wakefulness cycles, resulting in impaired performance and fatigue. We assessed the treatment efficacy of a hypnotic-psychostimulant combination to maintain sleep quality, performance, and alertness during a 42-h simulated military operation.


METHODS
A 6-h prophylactic sleep period with zolpidem (ZOL) followed by a 18-h continuous work period with administration at midway of 300 mg of slow release caffeine (CAF) or 200 mg of modafinil (MOD) was performed by eight healthy male subjects. Performance level was assessed with a reaction time test, a memory search test, a dual task, an attention test, and a computerized Stroop test. Cortical activation level was evaluated by the Critical Flicker Frequency test. Subjective sleepiness was evaluated using a visual analog scale and questionnaires. Effects of drugs on prophylactic and recovery sleep were also quantified from EEG recordings.


RESULTS
CAF and MOD maintained performance and alertness throughout the 18-h work period. As shown by EEG recordings, ZOL improved prophylactic sleep without any deleterious effect on performance immediately after waking. As a result of its positive effects on prophylactic sleep, a lower pressure for slow wave sleep during recovery sleep was observed; nevertheless, zolpidem did not enhance the effects of either psychostimulant on performance.


CONCLUSIONS
MOD and CAF may be of value in promoting performance and wakefulness during shiftwork or military operations while zolpidem improves prophylactic sleep quality without any deleterious effect after waking. We concluded that a zolpidem/ caffeine or modafinil combination could be useful in a context of environmental conditions not conducive to sleep.
Batéjat
Denise
D
Département de Physiologie Intégrée de l'Institut de Médecine Aérospatiale du Service de Santé des Armées (IMASSA), Brétigny sur Orge, France.
Coste
Olivier
O
Van Beers
Pascal
P
Lagarde
Didier
D
Piérard
Christophe
C
Beaumont
Maurice
M
D000328:Adult; D000337:Aerospace Medicine; D001288:Attention / Q000187:drug effects; D001559:Benzhydryl Compounds / Q000494:pharmacology*; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004569:Electroencephalography; D005221:Fatigue / Q000188:drug therapy; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects; D008887:Military Medicine; D000077408:Modafinil; D011725:Pyridines / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects; D012890:Sleep / Q000502:physiology; D014851:Wakefulness / Q000187:drug effects*; D014937:Work / Q000502:physiology; D000077334:Zolpidem
D001559:Benzhydryl Compounds; D000697:Central Nervous System Stimulants; D003692:Delayed-Action Preparations; D006993:Hypnotics and Sedatives; D011725:Pyridines; D002110:Caffeine; D000077334:Zolpidem; D000077408:Modafinil