22:  MELATONIN                                                       [Rev 6-16-2018]

This is one of the options in Step D1 (Section 46), for falling asleep.

Melatonin is a hormone that is normally produced by our pineal glands. It serves as a biochemical intermediary between external phases of light and dark and a person’s internal circadian pacemaker (Lavie, 2001).

(Zee and Reid 410) Normally a person’s body begins melatonin production about 2 hours before usual sleep onset, peaks about 3-5 hours into sleep time and then declines. It is typically undetectable by a couple of hours after the person’s usual waking time.

If the person is doing all needed to sleep normally and it still isn’t happening, it may be due to an inadequate production of melatonin. This would seem to suggest that the use of small doses of melatonin as a sleep-wake regulator could be effective if coupled with corresponding light management (Section 27). Its effects are less dramatic than common sleep medications, but there are also fewer side effects the day after taking it.

22a. How It Works

Production of natural melatonin is stimulated by the absence of daylight and suppressed by exposure to light. Waning daylight normally stimulates the body to produce melatonin, which then has its major effect on a person’s primary circadian clock in the anterior hypothalamus (Zee and Reid, 410). This effects the body’s circadian rhythms, including body temperature and need to sleep. Many circumstances can dysregulate this system, including the need to work at night, poor melatonin production, and blindness.

Prescription melatonin can supplement the body’s natural production, strengthening the circadian rhythms. Timing is important, so the two sources work together and not antagonistically.

Melatonin effectiveness is timing sleep is also dependent on ambient light. Indoor lighting can delay the effect of melatonin. Blue light from LEDs is more effective than incandescent light in suppressing melatonin release. Reading on an iPad has twice the effectiveness in suppressing melatonin production than reading a book (Walker, 269).

It can also be used to modify the body’s natural rhythms, moving them earlier or later. If melatonin is given in the afternoon or evening, when the core body temperature is going down, it moves the sleep-wake cycle earlier. If given in the early morning while body temperature is rising, it delays the sleep cycle, leading to later awakenings (Zee and Reid, 411).

22b. Sources

Melatonin can be purchased over the counter as a diet supplement, However, quality isn’t regulated in U.S. (Conroy, 175). Because of this, the purity and reliability of doses can be a problem. This lack of quality assurance may have led to uncertainty of research on melatonin, and any suggestions made here need to be taken cautiously and tested with specific products. Some assurance of reliability can be taken from a Good Manufacturing Practice [GMP] seal. (Sack 187)

It also comes in high tryptophan foods, such as milk, cookies, and bananas. (Reite, Weissberg and Ruddy, 79)

22c. Doses

Melatonin is typically sold in 1 mg and 3 mg tablet form. 3 mg doses are about 10times as great as physiological concentrations, but appear to be safe at that dose. In 3-5 mg doses, it may also have mild sedative properties (Glovinsky and Spielman, 155-156; Hauri and Linde, 130). Higher doses don’t appear to have a greater effect on circadian rhythms or the need for sleep. (Sack, 186)

The long-term effectiveness of melatonin in treating insomnia is not clear (Zee and Reid, 412). However, according to Hauri and Linde(130-131), long-term use of melatonin can reduce sex hormone production and blood flow to the person’s heart, and it may increase the depression of some people. If these are issues, a medical consultation may be in order.

22d. Treatment Applications

DIFFICULTY FALLING ASLEEP

If the person’s problem is difficulty falling asleep, melatonin in afternoon or evening should shift rhythms earlier, correcting a pathological phase delay. (Sack, 188) reducing sleep onset latency. However, it may not increase the person’s overall sleep time or reduce daytime sleepiness. It should be accompanied by a corresponding reduction in the amount of light that the person is exposed to as the target bedtime approaches (Zee and Reid, 410) . Patients should be advised that it takes from 45 minutes to three hours in order to be effective, and they may need to experiment with timing.

 

By contrast, RWR (p. 107) recommend a low dose (.3 mg) seven hours before a person’s normal biological sleep time, and using timed bright light an alarm clock to wake the person in the morning – at least until new sleep habits are established.

EARLY AWAKENING

If the problem is early awakening, administration in the latter half of the night or early morning may allow the person to sleep longer. This too should be accompanied by extending the observed darkness to the target awakening time, possibly through use of shades or blinds on windows.

The person should also be cautious about amounts taken in the morning, because of the possibility of drowsiness during the day (Sack, 190).

JET LAG OR NIGHT WORK

These issues are discussed with specific recommendations for the use of melatonin and bright light in two chapters by Burgess.

22e. Alternatives

Other similar medicatons, such as ramelteon have produced inconclusive results but might be helpful to some patients. Ramelteon has been approved by the FDA for treatment of insomnia (Zee and Reid, 412)