A warning about dopamine dysregulation syndrome has also been added to SPC as have following adverse effects: hallucinations, aggression and agitation, and syncope.
In April 2016, an MHRA Drug Safety Update warned that apomorphine can increase the risk of QT-prolongation at high doses. It noted that a review by EU medicines regulators of the safety of concomitant apomorphine and domperidone use had found that the risk of QT-prolongation may be increased in people on concomitant apomorphine and domperidone who have certain risk factors, including:
• pre-existing QT-interval prolongation
• serious underlying cardiac disorders such as heart failure
• severe hepatic dysfunction
• significant electrolyte disturbances
• concomitant drug therapy that may increase domperidone levels (e.g. cytochrome P450 3A4 inhibitors)
• concluded that health professionals should take precautions to reduce the risk of QT-prolongation
It recommended that patients receiving apomorphine and domperidone require an assessment of cardiac risk factors and ECG monitoring to reduce the risk of serious arrhythmia related to QT-prolongation.