Efficacy of 3 mg versus 6 mg Oral Melatonin in Improving Sleep Quality among Intensive Care Unit Patients: A Randomised Controlled Trial

Introduction: Melatonin, a molecule found in nearly all living organisms, plays a vital role in regulating circadian rhythm and sleep, while also influencing immune function, cell growth, and endocrine processes. Its role in improving sleep in Intensive Care Unit (ICU) patients remains under investigation. Aim: To compare the efficacy and safety of oral melatonin at two different doses (3 mg vs 6 mg) on sleep characteristics in ICU patients. Material and Methods: This single-centred, double-blinded, randomised controlled trial was conducted in the Department of Anaesthesiology and Critical Care, Pt. B. D. Sharma Pandit Bhagwat Dayal Sharma Postgraduate Institute of Medical Sciences (PGIMS), Rohtak, Haryana, India, on 46 adult ICU patients {≥18 years, Glasgow Coma Scale (GCS) ≥10}. Patients were randomly allocated to receive either 3 mg or 6 mg melatonin orally or via feeding tube at 9:00 pm for three consecutive nights, along with earplugs and eye masks. Sleep parameters were recorded from day 1 to day 3. Agitation was assessed using the Riker Sedation-Agitation (RSA) scale at 10:00 am and 6:00 pm. The length of ICU stay was noted. Data were analysed using Statistical Package for Social Sciences (SPSS) version 20.0, with p-value≤0.05 considered statistically significant. Results: Baseline demographics and American Society of Anaesthesiologists (ASA) status were comparable between groups. Total sleep time in the 3 mg group: 7.57±2.57 h (day 1) to 8.48±2.92 h (day 3); 6 mg group: 9.48±2.74 h to 9.93±2.55 h with no significant overall difference (p-value=0.780). Night sleep was higher on day 2 in the 6 mg group (p-value=0.009), but no significant overall trend (p-value=0.084). Day sleep, arousals, and RSA scores were non significant between the two groups (p-value>0.05), and the mean ICU stay was 4.35±1.46 days in the 3 mg group and 4.48±1.55 days in the 6 mg group, with no statistically significant difference between the groups (p-value=0.781). Both doses were well-tolerated without major adverse effects. Conclusion: Higher-dose melatonin (6 mg) significantly improved nocturnal sleep on one study day compared to 3 mg but showed no overall benefit in total sleep time, diurnal sleep, arousals, delirium, or sedation needs. Both doses were safe and well-tolerated.