Two studies have shown that domperidone may increase the risk of serious ventricular arrhythmias or sudden cardiac death, particularly in patients older than 60 years or taking doses greater than 30mg daily.
Domperidone should be avoided in patients taking medication that causes QT prolongation. Caution is required when treating patients with prolonged cardiac conduction intervals, significant electrolyte disturbances or underlying cardiac disease.
The lowest effective dose should be used and patients should seek prompt medical attention if symptoms such as syncope or tachyarrhythmia appear during treatment.