Ondansetron should be used cautiously in patients with a family history of cardiac arrhythmias. Monitoring ECG and electrolytes can help minimize risks.

For patients with a family history of arrhythmias, lower doses of ondansetron are recommended. Continuous cardiac monitoring during treatment can reduce the risk of adverse effects.

Patients predisposed to cardiac arrhythmias should consult a cardiologist before using ondansetron. Risk minimization includes avoiding other QT-prolonging drugs.