Effects of prophylactic ramosetron and ondansetron on corrected QT interval during general anesthesia.

STUDY OBJECTIVE: To evaluate whether ramosetron increases the corrected QT (QTc) interval. DESIGN: Prospective, randomized, controlled study. SETTING: Operating room. PATIENTS: 135 patients undergoing elective laparoscopic cholecystectomy. INTERVENTION: Patients were allocated to three groups to receive ondansetron 4 mg (Group O4), ramosetron 0.3 mg (Group R), or ondansetron 8 mg (Group O8). The study drugs were administered intravenously approximately 15 minutes before the end of surgery. MEASUREMENT: The QT interval for 10 minutes after administration was recorded. The QTc interval was calculated according to the Fridericia (QTcF) formula. The primary outcome was the QTcF interval among the three groups during the 10 minutes after administration of the study drugs. MAIN RESULTS: The QTcF interval was not significantly prolonged after administration of ondansetron 4 mg and ramosetron. It was significantly increased from one minute after administration until 7 minutes after ondansetron 8 mg (Group O8). The QTcF interval was significantly longer in Group O8 at 1, 2, 3, 4, and 5 minutes. CONCLUSIONS: The prophylactic administration 0.3 mg of ramosetron does not increase the QTc interval. Ondansetron 8 mg increases the QTc interval more so than 4 mg of ondansetron.