Melatonin Has Endocrine Risks For Children

Dave Kennaway, PhD Professor, Lloyd Cox Senior Research Fellow, Head Circadian Physiology Laboratory School of Paediatrics and Reproductive Health Robinson Research Institute, Faculty of Health Sciences, Medical School, University of Adelaide AustraliaMedicalResearch.com Interview with:
Dave Kennaway, PhD Professor

Lloyd Cox Senior Research Fellow,
Head Circadian Physiology Laboratory
School of Paediatrics and Reproductive Health
Robinson Research Institute,
Faculty of Health Sciences, Medical School,
University of Adelaide Australia

MedicalResearch: What is the background for this review? What are the main findings?

Dr. Kennaway: There is evidence that melatonin is being prescribed to for sleep disorders in children and adolescents who are developing normally despite the fact that there have been no properly designed studies on the effects of prolonged administration to children. In countries where melatonin has been registered, it is for use as a monotherapy for the short term treatment of primary insomnia, characterised by poor quality of sleep in patients who are aged 55 years and over. Use in Paediatrics is always “off-label”. After more than 50 years of melatonin research in animals there is overwhelming evidence that melatonin administration affects many organ systems. These include important effects on the reproductive organs of rodents, cats, ruminants and primates and melatonin is in fact registered as a veterinary drug for this purpose. The effects of melatonin, however, go beyond the potential reproductive consequences, including effects on cardiovascular, immune and metabolic systems. It is clear that many paediatricians, practitioners and parents are unaware of this.

MedicalResearch: What should clinicians and patients take away from your report?

Dr. Kennaway: Clinicians and patients need to recognise that melatonin is a hormone and not a drug developed for a specific purpose or illness. There have been no appropriate trials in children addressing the effects of prolonged administration of melatonin in children. Given the extensive literature on the role of the hormone in normal physiology it is unlikely that such trials would ever be approved. Should endocrine or other abnormalities appear in the future in children previously treated with melatonin it will not be tenable to argue that we were surprised.

MedicalResearch: What recommendations do you have for future research as a result of this study?

Dr. Kennaway: Clinicians and parents should not prescribe or self-administer melatonin to children or adolescents without full disclosure of information about the known actions of melatonin on reproductive and other systems in animal models and the disclosure that there is a lack of appropriate studies conducted in children. Then melatonin should be prescribed only after the strict diagnosis of Delayed Sleep Phase Syndrome, based on duration of the sleep onset insomnia, lack of response to sleep hygiene improving measures, realistic age related desired sleep time, sleep onset of more than 30 min on average and normal sleep architecture. Finally, the time of the natural increase in melatonin secretion, termed the Dim Light Melatonin Onset (DLMO) should be determined and compared with normal healthy age matched children. Prescription of melatonin without determining whether there is actually a circadian timing disorder would seem to be inappropriate.

Finally if melatonin is prescribed to children with appropriately diagnosed Delayed Sleep Phase Syndrome, there is little or no reason why treatment should continue beyond 3 or 4 weeks, certainly not for many years as has been reported. If the melatonin, in combination with good sleep hygiene and appropriate light exposure in the evening and morning does not bring about desired changes in onset of sleep, then it should be stopped and further investigations conducted to uncover the reasons for the sleep problem rather than escalating the dose. Concerns about the long-term safety of melatonin in children will become less of an issue.

Citation:

Potential safety issues in the use of the hormone melatonin in paediatrics
Kennaway DJ
J Paediatr Child Health. 2015 Feb 3. doi: 10.1111/jpc.12840. [Epub ahead of print]

MedicalResearch.com Interview with: Dave Kennaway, PhD Professor (2015). Melatonin Has Endocrine Risks For Children

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