IRCT2015082523760N1 IRCT 2016-10-25 Zanjan University of Medical Sciences The effect of melatonin tablet on sleep disorders in patients in cardiac surgery intensive care unit Effect of melatonin tablets compared to lorazepam tablets on circadian rhythm of sleep and serum level of leptin and cortisole and melatonin in CABG patients admited in heart ICU ward of Mousavi hospital, Zanjan 2016-04-20 anticipated 40 Complete https://irct.ir/trial/20250 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Other design features: Double blind clinical study (patients and researcher). 2-3 Sleep disorders. Intervention 1: Intervention group 1: 40 patient in Melatonin group will take 3 mg melatonin tablet for four nights. Intervention 2: Intervention group 2: 40 patient in Lorazpam group will take 2 mg lorazepam tablet for four nights.