All available
5-HT3-receptor antagonists (dolasetron,
granisetron, ondansetron,
palonosetron, tropisetron) have caused small increases (generally not exceeding 15 milliseconds) in the QTc interval. Some consider that these changes are not clinically relevant. Nevertheless, many of the manufacturers give various cautions about using
5-HT3-receptor antagonists together with other drugs that prolong the QT interval.
The UK manufacturer of dolasetron contraindicates the concurrent use of class I or class III antiarrhythmics, whereas the US manufacturer advises caution with all drugs that may prolong the QT interval. The UK manufacturer of ondansetron recommends caution in patients treated with antiarrhythmics or beta blockers (presumably sotalol) whereas the US manufacturer does not issue any cautions regarding QT-prolongation. The UK and US manufacturers of tropisetron recom- mend caution with other drugs that increase the QT interval.