Sleep is often described as one of the foundations of good health, along with diet, exercise, and relaxation. Poor sleep can cause and intensify a myriad of health disorders for nearly one-third of all Americans, according to the CDC.1

Given the prevalence of poor sleep in contemporary society, it’s likely that pharmacists will come across patients with some sort of sleep disorder in their practice. One potential remedy is supplemental melatonin, which mimics the endogenous hormone that regulates our circadian rhythm.2 With OTC melatonin readily available and its product awareness high among consumers, many pharmacists may be interested in learning more about its safety and efficacy before feeling comfortable recommending it to patients who are experiencing poor sleep.

The best evidence for the use of melatonin exists for delayed sleep phase syndrome (DSPS), non-24-hour sleep wake disorder (N24), and jet lag. In the first case, a person’s sleep is delayed by 2 hours or more beyond what is considered an acceptable bedtime; for the second, a person’s biological clock fails to synchronize to a 24-hour day; and with the third, there is a mismatch between the sleep-wake cycle of the person’s internal clock to the external cues in their surroundings, often due to travel.  

For patients suffering from any of these 3 conditions, taking 0.3 mg to 5 mg melatonin can reduce the length of time needed to fall asleep and improves overall quality of life.3 Although these benefits can dissipate within a year of stopping use of the drug, it has been shown to be safe and effective if taken regularly for up to 6 years.4

Specifically, in cases of jet lag, doses of 2 mg to 3 mg for those traveling eastward, when taken during the evening on the day of arrival for 2 to 5 nights, provides optimal benefit. However, studies have shown it may not be effective in decreasing the time to fall asleep or sleep efficiency, although it does improve alertness and psychomotor performance during wake time.5

The evidence for insomnia, in which a person has unsatisfactory sleep despite having adequate opportunity to sleep, is modest at best. Melatonin’s effect on insomnia in the short term has been demonstrated to shorten the time needed to fall asleep by only 7 to 12 minutes with a similar 8 to 12 minute increase in total sleep quantity.4 Comorbid conditions such as depression, schizophrenia, bipolar disorder, and epilepsy tended to benefit more from supplemental melatonin for the treatment of insomnia.4

Finally, shift work disorder and rapid eye movement sleep behavior disorder (RBD) do not seem to respond well to melatonin. In the former condition, patients complain of insomnia and excessive sleepiness as a result of a work schedule that takes place during normal sleep periods.
Taking melatonin doesn’t seem to improve time to fall asleep, sleep efficiency, or adjustments to rotating shifts.6 In the latter condition, patients with RBD act out vivid dreams with vocal sounds and sudden movements to the point where their sleep is disturbed. Muscle paralysis with melatonin use was also noted to increase in patients with RBD, though the evidence was not as strong.7

Poor sleep plagues our society in a number of ways. As front-line health care workers, pharmacists provide an easy and convenient resource for treatment and education among patients seeking to get a good night’s sleep.

Melatonin serves as an effective treatment option for those suffering from DSPS, N24, and jet lag. For insomnia, melatonin may have some potential benefit, whereas for shift-work disorder and RBD, melatonin will likely not provide much benefit. 

Overall, awareness of melatonin’s potential benefits and limitations can help pharmacists to more effectively serve patients suffering from poor sleep.

REFERENCES
  1. 1 In 3 adults don’t get enough sleep. Centers for Disease Control and Prevention. cdc.gov/media/releases/2016/p0215-enough-sleep.html. Published February 18, 2016. Accessed August 2020.
  2. Brzezinski A. Melatonin in humans. N Engl J Med. 1997;336:186-95. doi: 10.1056/NEJM199701163360306.
  3. Nagtegaal JE, Laurant MW, Kerkhof GA, et al. Effects of melatonin on the quality of life in patients with delayed sleep phase syndrome. J Psychosom Res. 2000;48:45-50. doi: 10.1016/s0022-3999(99)00075-6.
  4. Buscemi N, Vandermeer B, Hooton N, et al. Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis. BMJ. 2006;332:385-93. doi: 10.1136/bmj.38731.532766.F6.
  5. Sharkey KM, Fogg LF, Eastman CI. Effects of melatonin administration on daytime sleep after simulated night shift work. J Sleep Res. 2001;10(3):181-192. doi: 10.1046/j.1365-2869.2001.00256.x.
  6. Wright SW, Lawrence LM, Wrenn KD, et al. Randomized clinical trial of melatonin after night-shift work: efficacy and neuropsychologic effects. Ann Emerg Med. 1998;32:334-40. doi: 10.5847/wjem.j.1920-8642.2018.04.008.
  7. Kunz, D, Mahlberg R. A two-part, double-blind, placebo-controlled trial of exogenous melatonin in REM sleep behavior disorder. J Sleep Res. 2010;19(4):591-596. doi: 10.1111/j.1365-2869.2010.00848.x.