The effect of ondansetron therapy on QT interval to be detected by ECG in patients received intravenous ondansetron treatment in the emergency department

Ondansetron is a commonly used drug in the treatment of nausea and vomiting. There are few studies on the safety of this drug, which is known to cause QT prolongation. The aim of this study was to determine the magnitude of the QT interval increase associated with ondansetron. 435 adult patients were included in the study. ECG recording was obtained from the patients before the drug and at the 5th, 15th and 30th minutes after IV drug. In 51 patients (12%) of 4 mg and 384 patients (88%) of 8 mg of ondansetron were administered in a single dose. It was determined that the QT prolongation peaked at the 5th minute and remained constant at the 15th and 30th minutes. In the fifth minute, while 67,3% of patients had prolonged QTc interval, the rate of patients with long QT interval increased by 10,6%. The increase in QT interval was 7,9 ± 18,1 ms at the 5th minute, 6,7 ± 16,5 ms at the 15th minute and 6,5 ± 19,1 ms at the 30th minute. No cardiac conduction problems were observed in any patient. The average age of patients with longer QT interval was higher at all times. It was observed that the basal QT interval and the prolongation of the QT interval were higher in women. It was found that the basal QTc interval was longer and the rate of the patients who had QT prolongation was higher in the patients who had comorbid diseases and used QT prolonging drugs. It was found that the prolonged QT interval was not related to the dose of ondansetron. As a result, it was observed in this study that QT prolongation due to ondansetron administration was below the 'important' value according to the recommendations of the International Compliance Conference. In addition, no cardiac conduction disorder was detected in any patient. It can be said that 4 mg and 8 mg ondansetron IV administration at one time is safe in terms of QT prolongation risk in the emergency population without known risk of cardiac arrhythmia.