Melatonin Contraindications
Melatonin has few absolute contraindications, but should be used with caution in patients with epilepsy, those taking warfarin, patients with hepatic impairment, and is not recommended during pregnancy or lactation due to insufficient safety data. 1
Absolute Contraindications
- Pregnancy and lactation: Due to lack of sufficient human studies on safety during pregnancy and breastfeeding 2, 3
- Children under 2 years of age: Insufficient safety data in very young children 1
- Autoimmune diseases: Potential immunostimulatory effects may worsen symptoms
Relative Contraindications (Use with Caution)
Medical Conditions
- Epilepsy: Potential for interaction with seizure threshold 1
- Hepatic impairment: Decreased metabolism requires lower dosing 1
- Psychiatric disorders: May worsen symptoms in some conditions
- Hormone-sensitive conditions: Due to melatonin's effects on reproductive hormones 1
Medication Interactions
- Warfarin: May increase bleeding risk through interaction 1
- Serotonergic medications: Potential for serotonin syndrome
- Sedatives/hypnotics: Additive sedative effects
- Immunosuppressants: Potential immunomodulatory effects
- CYP1A2 inhibitors: May increase melatonin levels (e.g., fluvoxamine)
Special Population Considerations
Children and Adolescents
- Use with caution due to:
Elderly
- Start with lower doses (1-2 mg) due to:
- Altered metabolism
- Increased sensitivity to CNS effects
- Higher risk of morning drowsiness 1
Practical Safety Considerations
Dosing Precautions
- For most adults, doses of 5 mg or less are considered safe for short-term use 4
- Higher doses (≥10 mg) may increase risk of adverse effects like drowsiness, headache, and dizziness 4
- Long-term safety data (>6 months) is limited 5
Product Selection
- Look for USP (United States Pharmacopeia) verification to ensure stated dose accuracy 1
- Keep all melatonin products out of reach of children to prevent accidental ingestion 1
Monitoring Recommendations
- Monitor for adverse effects including:
- Daytime drowsiness
- Headache
- Dizziness
- Changes in mood
- Potential hormonal effects with long-term use
Alternative Approaches
- For insomnia, the American Academy of Sleep Medicine recommends prioritizing non-pharmacological approaches before considering melatonin 6, 1
- For circadian rhythm disorders, melatonin may be appropriate when properly timed 6
Remember that melatonin is regulated as a dietary supplement in the US rather than a medication, which means less stringent quality control and potential variability in actual content between products and batches.