Human data are from very short-term and relatively short-term treatment studies that were not designed to examine safety. Few studies included children.
Many of the available studies in humans included small numbers of participants and varied greatly in duration of treatment, from a single dose to dosing for a few weeks or months.
Few investigators described systematic collection of adverse effects in clinical trials.
There is uncertainty in the dose-response relationship for adverse effects.
The risk of harm from doses greater than 10 mg/day is unknown.
All future clinical trials should include systematic collection and evaluation of adverse effects.
Dose-dependent safety studies in adults and children are needed. These studies should include investigations of the potential for harm in individuals taking more than 10 mg of melatonin per day.
The literature should continue to be monitored for signs of melatonin effects on tumors and testes.
The long-term safety of melatonin use in adults and children needs further study. These studies should include close monitoring of individuals with cardiovascular disease, specifically hypotension.
More information is needed concerning possible interactions between melatonin and drugs, particularly various cardiovascular, psychotropic, and anticonvulsant drugs.
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