HYPNOTICS AND CAFFEINE AS COUNTERMEASURES FOR SHIFTWORK-RELATED SLEEPINESS AND SLEEP DISTURBANCE

Hypnotic medication reliably improves sleep during the day, in terms o f increasing total sleep time (TST) and reducing awakenings and light sleep. Middle-aged individuals may benefit more than young adults. In addition, the time of day during which sleep is attempted may influenc e the efficacious dose of short-acting drugs. Available data suggest t hat improving sleep during the day may improve alertness/performance a t night to a mild degree, but significant circadian-related sleepiness remains. Hypnotic medication may help minimize the cumulative effects of sleep loss associated with daytime sleep. Use for more than one we ek has not been adequately studied; however, as most night and rotatin g workers' schedules allow for night-time sleep for two or more nights per week, available evidence indicates that hypnotics can be used eff ectively on an intermittent basis, e.g. for the first 2-4 day-sleep pe riods of night shifts. Caffeine has been shown to increase alertness a nd improve psychomotor performance during usual night-shift hours when taken between 22.30 and 01.20 hours. Available data indicate that at approximate dosages of 250-400 mg, the beneficial effects persist unti l at least 05.30 hours. For most subjects, caffeine taken at the start of the night-shift does not interfere significantly with daytime slee p beginning at 0900 hours. There is also some evidence that single dos es of caffeine at the beginning of a night shift may be more alerting than divided doses. If caffeine is to be used therapeutically, avoidan ce of social use may be required to avoid tolerance to CNS stimulant e ffects. Despite the positive results of laboratory research examining hypnotics or caffeine as shiftwork countermeasures, field trials have not been conducted.