How does ondansetron cause QT prolongation?
Based on animal studies, 5-HT3 antagonists appear to prolong the QT interval by blocking IKr channels. In addition, these drugs block the cardiac sodium channels leading to QRS interval widening, which consequently prolongs cardiac depolarization and further lengthens the QT interval and can subsequently lead to TdP.
Can you take Zofran with long QT syndrome?
The label had previously warned about QT interval prolongation, but the new warning urges physicians to avoid the use of ondansetron in patients with congenital long QT syndrome.
Does long QT syndrome show up on an ECG?
In long QT syndrome, your heart’s electrical system takes longer than normal to recharge between beats. This delay, which often can be seen on an electrocardiogram (ECG), is called a prolonged QT interval.
How long does Zofran cause QT prolongation?
When used in patients with cardiovascular disease (eg, heart failure or acute coronary syndromes) with one or more risk factors for torsades de pointes, ondansetron may significantly increase the QTc interval for up to 120 minutes after administration.
Does ondansetron prolong the QT interval?
ECG changes including QT interval prolongation have been observed in patients receiving ondansetron. In addition, Torsade de Pointes, an abnormal, potentially fatal, heart rhythm, has been reported in some patients receiving ondansetron.
What is QT interval in ECG?
The QT interval is defined as the time duration between the onset of the QRS complex and the end of the T wave as it returns to baseline (fig 2), ideally measured using either lead II or lead V5 of the 12-lead ECG.
What antiemetic does not prolong QT?
Both ondansetron and granisetron prolong the QT interval when administered intravenously at doses over 8 mg and 10 micrograms/kg respectively. However, there have been no reports of QT prolongation following oral administration. Palonosetron and tropisetron are not associated with QT prolongation.
What ECG changes are associated with ondansetron?
ECG changes including QT interval prolongation have been observed in patients receiving ondansetron. In addition, Torsade de Pointes, an abnormal, potentially fatal, heart rhythm, has been reported in some patients receiving ondansetron. The use of a single 32 mg intravenous dose of ondansetron should be avoided.
Does ondansetron affect QTc interval in emergency department patients?
None of the patients had an ondansetron-related cardiac adverse event. Significant QTc prolongation occurred in ED patients receiving a single 4-mg i.v. dose of ondansetron. None of the patients had an ondansetron-related cardiac adverse event. Effect of a single dose of i.v. ondansetron on QTc interval in emergency department patients
Does Zofran (ondansetron) prolong QT?
The Zofran (ondansetron) drug labels already contain information about the potential for QT prolongation. The labels are being revised to include a warning to avoid use in patients with congenital long QT syndrome because these patients are at particular risk for Torsade.
What is the new FDA warning for ondansetron?
FDA is now adding a new warning to avoid the use of ondansetron in patients with congenital long QT syndrome because these patients are at particular risk for developing Torsade. Previous versions of the ondansetron labels included a warning on ECG interval changes (QT interval prolongation).