Emergency Medical Minute

Contributor: Taylor Lynch MD Educational Pearls: Melatonin is an endogenous hormone released primarily by the pineal gland Also released by extrapineal regions in the retina, the GI tract, and some immune cells Peak secretion occurs at night and is suppressed during the day Secretion and production decrease with age Older patients experience the greatest improvement in sleep latency and sleep quality Mechanism of action in the suprachiasmatic nucleus of the hypothalamus MT1 receptor Reduces normal firing MT2 receptor Shifts the circadian rhythm FDA approved for insomnia Decreases sleep latency by 7 minutes Increases total sleep time by 8 minutes FDA approved for circadian sleep-wake disorders Jet lag Most effective in west-to-east travel Best if crossing at least 5 time zones Shift work A study examined ED physicians and nurses with rotating shifts Modest increase in deep sleep percentage No difference in cognition or reaction time the day after taking melatonin Nurses on rotating nigh