摘要Objective: To compare effect of intrathecal meperidine, tramadol, magnesium sulfate, and dexmedetomidine on the prevention of post-spinal anesthesia shivering and adverse events in hip fracture repair patients.Methods: In a randomized, double-blind trial, 132 patients with American Society of Anesthesiology (ASA) Ⅰ and Ⅱ spinal anesthesia who needed hip fracture surgery were enrolled. Patients were stratified into 4 intervention groups based on a randomized block pattern: meperidine, tramadol, magnesium sulfate, and dexmedetomidine. Hemodynamic parameters including blood pressure, heart rate, and oxygen saturation, as well as the severity of shivering, core body temperature, Ramsay sedation score, adverse events, meperidine consumption were recorded and compared. Results: There was no statistically significant difference in the normal hemodynamic parameters, temperature, duration of surgery, meperidine consumption, and adverse events such as dizziness, hypotension, nausea, and bradycardia among groups (P>0.05). Compared to other groups, severity of shivering was the lower in the dexmedetomidine group 6 and 8 h after surgery. The Ramsay sedation scores were higher in the dexmedetomidine and meperidine groups 4 h after surgery (P=0.020). Conclusion: Dexmedetomidine acts better than the other three adjuvants in reducing complications such as shivering. Overall, these four adjuvants are helpful to prevent postoperative shivering and could be put forward as promising local anesthetics in spinal anesthesia, based on anesthesiologists' discretion and patients' general conditions.Clinical registration: The study was approved by the Research and Ethics Committee at the Valiasr Hospital (Arak, Iran) with the clinical trial code of IRCT20141209020258N153.