What is the recommended dosage of melatonin (melatonin) for a typical adult patient with a sleep disorder, considering factors such as age and medical conditions like diabetes and high blood pressure?

Melatonin Dosage for Adults with Sleep Disorders

For typical adult patients with sleep disorders, the American Academy of Sleep Medicine explicitly recommends AGAINST using melatonin for chronic insomnia (sleep onset or maintenance problems), but when used for circadian rhythm disorders like delayed sleep-wake phase disorder, the recommended dose is 3-5 mg of immediate-release melatonin taken between 19:00-21:00 for at least 28 days. 1, 2

Primary Insomnia: Do Not Use Melatonin

• The American Academy of Sleep Medicine provides a weak recommendation AGAINST melatonin for primary insomnia in adults due to minimal efficacy—only a 9-minute reduction in sleep latency compared to placebo 1
• Melatonin shows poor performance for sleep maintenance, total sleep time, and quality of sleep, with very low quality evidence 3
• For primary insomnia, consider FDA-approved hypnotics instead (zolpidem 10 mg, eszopiclone 2-3 mg) 1

Circadian Rhythm Disorders: When Melatonin IS Appropriate

For Delayed Sleep-Wake Phase Disorder (DSWPD):

• Start with 3-5 mg immediate-release melatonin 1, 2
• Take between 19:00-21:00 (7-9 PM) 1, 2
• Continue for minimum 28 days to assess effectiveness 1, 2

For Non-24-Hour Sleep-Wake Rhythm Disorder (blind patients):

• Use 0.5-10 mg melatonin, typically starting at 5 mg 1
• Take either 1 hour before preferred bedtime or at fixed time (21:00) 1
• Continue for 26-81 days 1

Special Considerations for Your Patient's Comorbidities

Diabetes:

• Exercise caution—melatonin has been associated with impaired glucose tolerance in healthy individuals 4
• Monitor fasting glucose periodically if using melatonin 4

Hypertension:

• No specific contraindication, but monitor blood pressure as part of routine care
• Melatonin does not have documented significant interactions with common antihypertensive medications 4

Elderly Patients (>55 years)

• Prolonged-release melatonin 2 mg may provide modest benefit for elderly patients, though evidence quality is low 3, 1
• The recommendation against melatonin for primary insomnia still applies to elderly adults 1
• For circadian disorders in elderly, use the same 3-5 mg dosing as younger adults 1, 2

Critical Dosing Principles

• Start low: Begin with 3 mg immediate-release melatonin 1, 2
• Titrate cautiously: If ineffective after 1-2 weeks, increase by 3 mg increments 2, 4
• Maximum dose: 12-15 mg (doses above 10 mg risk receptor desensitization with no additional benefit) 1, 4
• Timing matters: Taking melatonin at wrong times (morning/afternoon) worsens circadian misalignment 4

Common Pitfalls to Avoid

• Wrong indication: Do not prescribe melatonin for primary insomnia—it simply doesn't work well enough 1
• Wrong formulation: Slow-release/prolonged-release melatonin is less effective than immediate-release for sleep onset 2
• Product quality: Melatonin is a dietary supplement in the US with variable quality; choose United States Pharmacopeial Convention Verified formulations when possible 1, 4
• Drug interactions: Use caution with warfarin and in patients with epilepsy 1, 2, 4

Adverse Effects Profile

• Common mild side effects include morning headache, morning sleepiness, and gastrointestinal upset (more frequent at higher doses) 1, 4
• Higher doses (≥10 mg) increase risk of morning grogginess and "hangover" effects 4
• No serious adverse reactions documented across age groups when used at appropriate doses 1, 2

Duration of Treatment

• For chronic insomnia: Maximum 3-4 months (though again, not recommended as first-line) 4
• For circadian rhythm disorders: May be used longer-term as these conditions require ongoing chronobiotic therapy 4
• Reassess need for continued therapy every 3-6 months 4
• Consider periodic dose reduction or frequency tapering (every other night) to determine lowest effective dose 4

Algorithm for Your Patient

1. Identify the sleep disorder type:

   • If primary insomnia (difficulty falling/staying asleep without circadian component): Do NOT use melatonin; consider FDA-approved hypnotics 1
   • If delayed sleep-wake phase disorder or other circadian disorder: Proceed with melatonin 1, 2

2. If circadian disorder confirmed:

   • Start 3 mg immediate-release melatonin at 19:00-21:00 1, 2
   • Continue for 28 days minimum 1, 2

3. Assess response at 2-4 weeks:

   • If effective: Continue at current dose
   • If ineffective and no adverse effects: Increase to 5 mg 1, 2
   • If still ineffective at 5 mg: Consider increasing to maximum 10 mg, though benefit unlikely 1, 4

4. Monitor for:

   • Fasting glucose (given diabetes history) 4
   • Morning grogginess or daytime sleepiness 4
   • Sleep diary outcomes (sleep latency, total sleep time) 2