Melatonin is being increasingly used on an over-the-counter basis by patients, both adult and pediatric, for sleep disturbance, both for difficulty initiating sleep and maintaining sleep. When suggested or prescribed, it is also advisable to incorporate guidance about sleep hygiene habits and to encourage patients to get ample exposure to bright sunlight and appropriate levels of exercise during the day.
In humans and other animals, it is a hormone that participates in circadian rhythms and anticipates the daily onset of darkness. It is also an antioxidant and participates in the protection of nuclear and mitochondrial DNA. It is directly synthesized from the amino acid L-tryptophan, which has also historically been used as a supplement for sleep. The human body produces endogenous melatonin about two hours before bedtime, provided that the light is dim, and helps prepare the body for sleep. An infant’s melatonin levels become regular around 3 months. Also as children become adolescents, their bodies release melatonin later in the evening, leading to a delay in sleep onset and wake up time. Human melatonin production decreases as a person gets older so it may be of particular benefit for this population.
Research has shown that supplemental melatonin can be helpful in improving onset of sleep, sleep quality and sleep latency. It has been studied for insomnia in elderly patients. It has been found helpful for treating sleep-wake cycle disorders in children with underlying neurodevelopmental difficulties, like Autism and ADHD. It can be helpful to treat sleep disturbance side effects of other medications, like stimulant medications. The medication has also been found to be helpful to treat jet lag and for those doing shift work where the normal circadian rhythm may be impacted. Additionally, there is some data to suggest that blind individuals and patients with Alzheimer’s may show benefit with their sleep profile.
Melatonin is widely available in a variety of forms – pill, chewable, liquid, and sublingual. Side effects, while not common, can include morning sleepiness, headache, short-term feelings of depression, dizziness, stomach cramps and irritability. A typical dose range for adults is between 2-10mg and for children can be as low as 0.5 mg up to 6mg. The dose can be titrated rapidly to an effective level. Use of melatonin in pregnancy and for nursing mothers is generally not recommended as there is limited evidence as to its impact on the fetus or newborns. Finally, there is some evidence that melatonin can stimulate immune function leading to recommendations that it not be used with patients who have autoimmune conditions.
Immediate-release formulations cause blood levels of melatonin to reach their peak in about 1 hour. Melatonin is available as a prolonged-release prescription medication, Circadian, which releases melatonin gradually over 8-10 hours. This is intended to more closely mimic the body’s internal release of melatonin. The medication comes in a 2mg dose and has been well studied. This form might be more helpful than the immediate-release form for patients who struggle with maintaining sleep.
Melatonin can be a useful early choice for patients, pediatric and adult, who are struggling with sleep disturbance. It seems to be safe for long term use, although this has not been extensively studied
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