Severe Hypotension in an Adolescent After a Melatonin Overdose

Vital signs were blood pressure 126/99 mmHg, pulse 82 beats/min, respiratory rate 14 breaths/min, and pulse oximetry was 100% on room air. [...]10 hours later, orthostatic vital signs revealed a 45/24 mmHg decrease in blood pressure from supine (107/69 mmHg) to sitting (62/45 mmHg) (Fig. 1). The mechanism of melatonin's blood pressure lowering effects remains unclear, but may be related to nitric oxide formation causing vasodilation, parasympathetic stimulation, or calcium metabolism (Pechanova et al. 2014).