Reduction of the rocuronium-induced withdrawal reflex by MR13A10A, a generic rocuronium with a novel solution: A randomized, controlled study

BACKGROUND: Rocuronium induces venous pain and the withdrawal reflex during injection. MR13A10A, generic rocuronium with a novel solution, reduced the injection-induced withdrawal reflex in rodents. We hypothesized that MR13A10A would reduce the frequency and severity of injection-induced withdrawal reflexes compared with original rocuronium during clinical anesthesia induction. METHODS: This prospective, open (but assessor-blinded), randomized, controlled study was conducted at a single academic hospital. The assessor was blinded to the study condition in order to minimize observer bias. Participants were allocated to either MR13A10A or traditional formula groups by a blocked stratified randomization method. Participants in the MR13A10A group received MR13A10A, whereas the original rocuronium group received the same amount of original rocuronium. The primary outcome was presence of the withdrawal reflex after rocuronium injection. Severity of the withdrawal reflex, changes in blood pressure and heart rate, and the train of four (TOF) ratio were measured as secondary outcomes. The withdrawal reflex was assessed using a video recording in a blinded manner. RESULTS: Of the 149 participants, 76 were allocated to the MR13A10A group and 73 to the original rocuronium group. The frequency of the withdrawal reflex was significantly lower with MR13A10A compared with original rocuronium (19.7% and 54.8% for MR13A10A and original rocuronium groups, respectively, p<0.001). The odds ratio adjusted for cannulation site, cannula size, induction agent and age was 6.27 (95% CI, 2.87, 13.73 p<0.001). Original rocuronium was an independent factor related to a higher post-treatment heart rate. The proportions of TOF ratios = 0 were similar between the two groups. CONCLUSION: The frequency and severity of the withdrawal reflex after injection were significantly reduced by using MR13A10A. MR13A10A might contribute to safe and less invasive anesthesia management.