Comparison of Two Different Doses of Magnesium Sulfate on the Prevention of Pain During Etomidate Injection

Abstract

Background: Etomidate is a relatively safe drug that is used in short-term anesthesia. Despite the many benefits, patients complain of pain during injection. Previous studies have recommended a dose of 620 mg of magnesium sulfate to reduce pain in patients. In this study, we tried to investigate different doses of magnesium sulfate for the prevention of pain caused by etomidate injection and its complications. Methods: In this triple-blind clinical trial, 90 patients aged 18 to 65 years, who were candidates for surgery under general anesthesia, after meeting the inclusion and exclusion criteria, were randomly divided into three groups (magnesium sulfate 50 750 mg, magnesium sulfate 50 1 gram, and normal saline as control). Magnesium sulfate was administered prior to etomidate injection. Patients were monitored for background characteristics and vital signs before surgery. Findings: The mean age of the patients was 41.73 ± 17.22 years, and 60.75 of the patients were male. The diastolic blood pressure and heart rate before etomidate injection were higher in the 50 magnesium sulfate group with a onegram dose (P < 0.05). The duration of surgery, anesthesia and extubation in the group receiving 750 mg of 50 magnesium sulfate was longer than that in the 1 gram dose group (P < 0.05). The intensity of initial pain, as well as pain after 10 minutes and the change in pain after 10 minutes compared to the initial pain, did not differ among the three groups (P > 0.05). Patients with a higher dose had an increase in diastolic blood pressure but a decrease in mean blood pressure in the first 10 minutes (P < 0.05). Conclusion: Although the two different doses of magnesium sulfate did not show significant analgesic effects compared to each other, the use of a 1-gram dose was more successful than 750 mg in controlling mild to moderate pain. © 2026, Isfahan University of Medical Sciences(IUMS). All rights reserved.