The Effect of Locally Administered Dexmedetomidine on Postoperative Pain in Patients Undergoing General Anesthesia for Perianal Surgery: A Comparative Randomized Clinical Trial

Background: Perianal surgery can cause a considerable amount of pain, which requires appropriable management.Aim: This study was performed with aim to evaluate the effect of local dexmedetomidine administration on postoperative pain in patients undergoing general anesthesia for perianal surgery.Method: This double-blind randomized clinical trial was conducted on patients undergoing general anesthesia for perianal surgery at Ghaem Hospital in Mashhad, Iran, between June 2020 and June 2020. Patients were randomly allocated to dexmedetomidine (DEX) or control groups. All patients underwent the same process for anesthesia. The patients in the DEX Group received a local injection of 1.5 μg/kg dexmedetomidine in 10ml of normal saline around the operation site at the end of the surgery and the control group did not receive any local injection. The primary outcome was post-operative pain scores in the first 24h after surgery.Results: The DEX group exhibited significantly reduced pain scores at rest in 1, 3, 6, 12, and 24 hours after the surgery (p= 0.004, 0.010, 0.001, and 0.008, respectively). Furthermore, the pain scores in the DEX group were lower than the control group at the same time intervals after the operation (p=0.000, p=0.001, p=0.001, and p=0.015, respectively). The consumption of paracetamol and methadone was also significantly lower in the DEX group than in the control group at 3, 6, and 12 hours after surgery (p=0.010, p=0.003, and p=0.008, respectively).Implications for Practice: Local perianal administration of dexmedetomidine reduces postoperative pain scores and analgesic consumption in patients undergoing general anesthesia for perianal surgery.