What are the long-term effects of giving melatonin (melatonin) to children?

Long-Term Effects of Melatonin Use in Children

Melatonin supplementation in children should be used with caution due to limited long-term safety data and potential effects on hormonal development, with regular monitoring and periodic discontinuation attempts recommended. 1

Efficacy and Short-Term Safety

Melatonin has demonstrated effectiveness for specific sleep disorders in children:

• Effective for improving sleep latency (time to fall asleep) by 22-60 minutes in children with sleep disorders 2
• Particularly beneficial for children with autism spectrum disorders (ASD), showing improvements in sleep latency and total sleep time 3
• Most effective when administered 3-5 hours before the child's natural dim light melatonin onset 4

Short-term adverse effects are generally mild and include:

• Daytime sleepiness (1.66%)
• Headache (0.74%)
• Dizziness (0.74%)
• Other sleep-related issues (0.74%) 5

Long-Term Safety Concerns

The American Academy of Sleep Medicine highlights several concerns about long-term melatonin use in children:

• Potential effects on growth hormone regulation
• Possible impacts on reproductive function and development
• Limited long-term safety data from randomized controlled trials 1

While acute toxicity studies in animals show toxic effects only at extremely high doses (>400 mg/kg), the long-term hormonal effects remain a concern 2. Melatonin is known to have profound effects on reproductive systems in animal models 6.

Monitoring Recommendations

For children who are prescribed melatonin:

• Regular monitoring for efficacy and side effects is essential
• Periodic attempts to discontinue melatonin treatment are recommended to assess continued need
• Treatment should be stopped at least once a year (preferably during summer holidays) to reassess circadian rhythmicity 1, 2
• Consultation with a pediatric sleep specialist is recommended rather than self-administration 1

Dosing Considerations

Appropriate dosing varies by condition:

• For children with delayed sleep-wake phase disorder (DSWPD) without comorbidities: 0.15 mg/kg taken 1.5-2 hours before habitual bedtime
• For children with DSWPD and psychiatric comorbidities: 3-5 mg (weight-based) taken at 18:00 or 19:00 1
• Extended-release formulations may be considered for children with neurodevelopmental disorders 1

Important Precautions

• Decreased CYP 1A2 activity (genetic or medication-induced) can slow melatonin metabolism, potentially leading to loss of effect; decreasing the dose can address this issue 4
• Special caution is needed for patients with epilepsy, hepatic impairment, or those taking warfarin due to potential interactions 1
• Melatonin should be considered only after behavioral interventions and improved sleep hygiene have failed 7

Alternative Approaches

Before initiating melatonin, consider these non-pharmacological interventions:

• Optimize sleep environment (dark, quiet, cool bedroom)
• Maintain consistent sleep-wake schedules
• Reduce evening exposure to blue light from electronic devices
• Remove electronic devices from the bedroom 1

While melatonin appears relatively safe in the short term, the lack of comprehensive long-term safety data in children warrants a cautious approach with regular reassessment of its continued need.