Efficacy of an Oral Melatonin Suspension in Idiopathic Nocturnal Irritability among Infants Older than 6 Months: A Randomized, Single-blind, Quasi-experimental Trial.

OBJECTIVE: Excessive or frequent night waking in infants can cause significant parental distress, maternal fatigue, family dysfunction, and increased risk of depression and anxiety. Melatonin, a hormone secreted in response to darkness, regulates the sleep-wake cycle. Infants with sleep difficulties may have low melatonin levels; therefore, melatonin supplementation may help improve sleep. This study evaluated the efficacy of an oral melatonin suspension in infants with idiopathic nocturnal irritability. METHODS: In this randomized, single-blind quasi-experimental clinical trial, infants aged 6-24 months with idiopathic nocturnal restlessness were assigned to receive either oral melatonin (0.1 mg/kg nightly) or a matching placebo for 14 days. Sleep parameters were recorded by parents at baseline and reassessed after treatment. Infants with organic causes of restlessness, sedative medication use, hypersensitivity, or poor adherence were excluded. Data were analyzed using appropriate statistical tests with a significance level of P < 0.05. FINDINGS: Sixty-seven infants were enrolled; 60 completed the study (30 melatonin and 30 placebo). After 14 days, the melatonin group showed significant reductions in nocturnal awakenings, sleep onset latency, and total nocturnal wakefulness, along with significant increases in longest continuous sleep duration and total sleep time. No significant changes occurred in the placebo group. CONCLUSION: Melatonin at 0.1 mg/kg appears to be effective and safe as an adjunctive therapy for idiopathic nocturnal restlessness in infants. Further studies with larger samples and longer follow-up are recommended.