Emergent Care / Stabilization:
While most melatonin overdoses are asymptomatic or have mild symptoms that do not require intervention, rarely some have severe symptoms. Rapid assessment of the ABCs (airway, breathing, circulation) is essential in an impaired child with a suspected overdose. Supplemental oxygen and respiratory support should be provided as needed. Intravenous (IV) lines should be initiated and fluid resuscitation and/or pressor support initiated as needed. Treatment is supportive. Screening for coingestions is imperative.

Diagnosis Overview:
Melatonin is a naturally occurring endogenous neurohormone produced by the pineal gland that helps to regulate sleep-wake cycles in humans. Synthetic melatonin is widely available in the United States as an over-the-counter dietary supplement that is commonly used to address sleep-wake cycle dysregulation in both children and adults. The use of melatonin to address sleep problems has increased markedly over the last 5 years.

Melatonin supplements are available in many different formats, including liquids, chewable tablets, gummies, and pills. Some of these formats are appealing to young children (eg, gummies), and the packaging lacks childproofing, allowing for unintentional ingestions / overdoses by children. Additionally, studies of melatonin supplements show large variations in actual melatonin content compared to the labeled values, with some containing over 400% more melatonin than indicated on the bottle.

The incidence of unintentional melatonin ingestion, especially in children younger than 5 years, has risen markedly over the last 10 years and now accounts for up to 5% of all pediatric ingestions reported to poison control centers. The actual number of accidental ingestions is likely much higher than those reported due to underreporting.

Most melatonin ingestions are asymptomatic and do not require medical interventions; however, in rare cases, they can be severe and life-threatening. The data on symptoms of a melatonin overdose are not well documented in the medical literature. The most common symptoms reported are lethargy, disorientation, dizziness, and mental status changes. Some children noted headaches and vertigo. Nausea, vomiting, and diarrhea have been reported. More severe, very rare symptoms include hypotension or hypertension, tachycardia, and respiratory compromise severe enough to require mechanical ventilation. Approximately 15% of melatonin overdose referred to the emergency department (ED) by a poison control center had symptoms severe enough to warrant admission, with 1% requiring intensive care unit (ICU) care. At least 2 pediatric deaths have been attributed to melatonin overdose.