BackgroundTranexamic acid and vitamin C are potent antifibrinolytic and oxidative stress agents that reduce blood loss and transfusion blood in cardiopulmonary bypass (CPB).ObjectivesThe aim of this study was to evaluate the efficacy of tranexamic acid (TA) and tranexamic acid combined with vitamin C (TXC) on drainage volume (blood loss) and atrial fibrillation (AF) in patients undergoing cardiac bypass surgery in Gorgan, Shafa hospital, Iran.MethodsThis study is a double-blind randomized clinical trial. A sample size of 120 candidates of cardiac bypass surgery were included in this prospective study. Patients were randomly assigned to treatments in two groups. In both groups, 50 mg/kg tranexamic acid was administered intravenously directly before sternotomy: group A (N = 58) patients received tranexamic acid (TA) only and group B (N = 62) tranexamic acid with vitamin C (TXC) half an hour before surgery and 2 g vitamin C with 100 mL 0.9% saline were injected. Subsequently, during 4 days after surgery, 1000 mg of vitamin C and 100 cc 0.9% saline was infused every day. Intraoperative and postoperative blood loss (volume of blood in the drain) and atrial fibrillation complications were recorded for 24 hours after the operation.ResultsThe patients who received vitamin C had less bleeding during operation and in the early hours post-operation. Patients in (TA) group had mean drainage of 34.41 milliliter more than patients in (TXC) group (P < 0.001). Chi-square test showed that arrhythmia (AF) condition was the same in the two groups during 14 times of study (four times during operation and ten times up to 24 hours after the operation), and AF arrhythmia in the two groups was less than 5%.ConclusionsIn this study tranexamic acid with vitamin C have a positive effect on the amount of drainage (blood loss) and there was no significant difference in the incidence of AF between two groups.