Tehran University of Medical Sciences Frontiers in Emergency Medicine 2717-3593 5 3 2021 03 14 e32 e32 EN Majid Shohrati Department of Pharmacotherapy, Faculty of Pharmacy, Baqiyatallah University of Medical Sciences, Tehran, Iran Amir Mohammadi Student Research Committee, Faculty of Pharmacy, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Atabak Najafi Department of Anesthesiology and Critical Care, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran Mohammad Sharifzadeh Department of Pharmacology and Toxicology, Tehran University of Medical Sciences, Tehran, Iran Hamidreza Sharifnia Department of Anesthesiology and Critical Care, Sina Hospital, Tehran University of Medical Sciences, Iran. Mohammad Abdollahi Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS) and Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Mahmood Salesi Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran Adeleh Sahebnasagh Clinical Research Center, Department of Internal Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran Mojtaba Mojtahedzadeh Department of Clinical Pharmacy, Pharmaceutical Research Institute, Tehran University of Medical Sciences, Tehran, Iran 2021 02 19 2021 03 07 Introduction: Considering that hemorrhagic stroke patients are at higher risk for bleeding, administration of higher doses of melatonin with a controversial coagulation profile is a serious concern. Objective: This study aimed to investigate the possible effects of high doses of melatonin on bleeding parameters and blood hemostasis in hemorrhagic stroke patients. Methods: This study is a randomized, double-blind, prospective, controlled trial. Confirmed hemorrhagic stroke patients were divided into two groups. Participants were randomly assigned into the melatonin group (30 mg daily via gastric tube gavage for 5 consecutive days) or the control group. Each patient was monitored for 5 days, and 2 blood samples were taken and the effect of the intervention on coagulation factors and blood hemostasis were investigated. Result: In total, 30 patients were randomly assigned to melatonin (n=15) or control groups (n=15). there was no significant difference between the two groups in demographic and clinical characteristics. There was a significant decline in prothrombin time (PT) and fibrinogen levels in the melatonin group (p=0.011 & p<0.001, respectively). P-values for VII and VWB factors showed a significant increment in these two factors in the melatonin group after the intervention (p=0.035 & p=0.002, respectively). No significant changes in serum levels of D-dimer factor, APACHE II, and GCS scores were evident in the two groups after the intervention (p>0.05). Conclusion: Considering the favorable changes in coagulation parameters observed in this study, it could be concluded that melatonin can have both procoagulant and antithrombin properties. https://fem.tums.ac.ir/index.php/fem/article/view/671 https://fem.tums.ac.ir/index.php/fem/article/download/671/347