[Role of the pharmacopoeia in the prevention of jet-lag].

Long-haul flights allow rapid crossing of times zones. When four time zones are crossed, the transmeridian flight induce jet-lag syndrome. Jet-lag is essentially composed of digestive and behavioural disturbances (insomnia and/or drowsiness). It is due to an immediate conflict between external time cues, which have been phase-advanced or phase-delayed by eastward or westward flight, respectively, and the endogenous clock. This conflict induces a desynchronization of the biological rhythms. Different counter-measures could be advised, but the most used is the pharmacological one. Hypnotics like benzodiazepines, cyclopyrones or imidazopyridines induce a recovery sleep but could also induce secondary effects in case of chronic use. Melatonin secreted by pineal gland needs more studies before a safety use for jet-lag treatment. Psychostimulants are able to induce a prolonged wakefulness. But amphetamine-like substances have to be forbidden because of the importance of side effects. New researches are studying a new galenic form of caffeine: the time release caffeine, which permits to induce a long and good quality wakefulness.