MELATONIN - THERAPEUTIC USE IN SLEEP DISORDERS

OBJECTIVE: To review the use of melatonin in sleep disorders, includin g jet lag, shift work disorder, insomnia, and sleep cycle disorders in neurologically impaired patients. DATA SOURCE: A MEDLINE search (1966 to April 1996) was performed that included clinical studies and revie ws on melatonin in the English language. References used in those arti cles were also screened for additional information, STUDY SELECTION: A ll published trials were considered for inclusion in this review, with an emphasis placed on more recently published studies (last 5 years), DATA SYNTHESIS: There is significant evidence that links the hormone melatonin to circadian sleep cycles in humans. II has been suggested t hat in situations where the endogenous melatonin concentration is redu ced (advancing age) or the normal circadian cycle is disrupted (jet la g, shift work blind patients), supplementation with exogenous melatoni n may improve both sleep duration and quality. Limited data from gener ally short-term trials and anecdotal reports suggest that melatonin ma y be effective in several of these sleep disorders. Melatonin use in j et lag appears to decrease jet lag symptoms and hasten the return to n ormal energy levels, Melatonin mg be helpful in relating shift schedul es to improve sleep quality and maintain normal circadian rhythm In so me patients with insomnia, melatonin appears to induce sleep onset. Th e optimal dosage and tinting of drug administration is still unclear. CONCLUSIONS: Although there is some evidence that melatonin may have m odest efficacy, especially in insomnia, jet lag, and sleep disorders i n neurologically impaired patients, adequate long-term studies examini ng both efficacy and toxicity are lacking. In addition, further studie s evaluating dose-response relationships and drug interactions are war ranted.