Melatonin Dosing for Insomnia

Direct Recommendation

• The American Academy of Sleep Medicine explicitly recommends against using melatonin for chronic insomnia in adults, as the evidence shows no clinically significant benefit for sleep onset or maintenance at the studied 2 mg dose 1, 2

Evidence-Based Dosing by Clinical Context

For Chronic Insomnia (NOT Recommended)

• Melatonin is not recommended for treating chronic insomnia based on the 2017 American Academy of Sleep Medicine guideline, which found only a 9-minute reduction in sleep latency compared to placebo with 2 mg doses—below the threshold for clinical significance 1
• The quality of evidence was very low due to publication bias, heterogeneity, and imprecision, with benefits approximately equal to harms 3, 2

For Elderly Patients (≥55 Years) with Specific Indications

• The 2 mg dose showed approximately 19 minutes reduction in sleep latency in elderly patients (>55 years) compared to placebo 3

For Circadian Rhythm Disorders (Delayed Sleep-Wake Phase Disorder)

• Use 5 mg melatonin administered between 19:00-21:00 (7-9 PM), which is 1.5-2 hours before desired sleep onset, for a minimum of 28 days 4, 2
• This represents a weak recommendation based on low-quality evidence but showed reduction in sleep latency by 38-44 minutes and increased total sleep time by 41-56 minutes 2

Formulation Considerations

• Prolonged-release (sustained-release) formulations are preferred over immediate-release for maintaining sleep throughout the night and mimicking normal physiological circadian rhythm 3

Dosing Pitfalls to Avoid

• Do not increase dose beyond 5 mg—escalation provides no definitive additional benefits 4
• Timing matters more than dose: administration at bedtime rather than 1-2 hours before is a common error that reduces efficacy 2

Special Populations

Renal or Hepatic Impairment

• No specific dose adjustments are provided in guidelines for renal or hepatic impairment, as melatonin has a favorable safety profile with minimal adverse effects 3
• Monitor for additive sedation if patients are on multiple CNS-active medications 3

Drug Interactions

• No significant drug-drug interactions exist between melatonin and common medications including doxepin, propranolol, or SSRIs, but monitor for additive sedation 3
• Melatonin is not listed on the American Geriatrics Society Beers Criteria, representing a safer option than many alternatives in elderly patients 3

Duration and Monitoring

• Trial duration: Minimum 3-4 weeks to assess efficacy before considering dose adjustment 3