BACKGROUND Adenotonsillectomy is a safe and common operation to remove adenoids and tonsils. Here we decided to compare the two dosages of tranexamic acid and their effects on hemodynamic changes and anesthesia-related indexes during surgical interventions. METHODS This is a double-blinded clinical trial performed in 2019-2020 on 64 children who were candidates for adenotonsillectomy. The patients were randomly divided into
two groups of 32 based on the table of random numbers. Group A received 5 mg/kg slowly tranexamic acid for 10 minutes and group B received 10 mg/kg tranexamic acid slowly for 10 minutes. The study protocol was approved by the Research committee of Isfahan University of Medical Sciences and the Ethics Committee has confirmed it (Ethics code: IR.MUI.MED.REC.1398.639) (Iranian Registry of Clinical Trials (IRCT) code: IRCT20171030037093N33, https://en.irct.ir/trial/46553). RESULTS The mean volume of intraoperative bleeding in children in group A is significantly higher than in children in group B (P < 0.05). However, no significant difference was observed between the length of stay in recovery and the duration of extubation and the mean dose of propofol in the two groups (P > 0.05). The mean arterial oxygen saturation of children in both groups increased significantly over time (P < 0.05). However, no significant difference was observed between the two groups (P > 0.05). According to the results, the mean HR in both groups decreased significantly over time (P < 0.05). In addition, the mean HR in children in the group B was significantly lower than children in the group A (P < 0.05). CONCLUSION Administration of 10 mg/kg of tranexamic acid during tonsillectomy is associated with lower amounts of bleeding and lower heart rate than 5 mg/kg dosage. These results were in line with most previous studies.