Answer
It can prolong the QT interval and rarely cause serious abnormal rhythms. Cardiac history, interacting medicines, ECG findings and electrolytes are important.
Sources for this answer
- HALDOL Decanoate 50 mg/ml solution for injection and HALDOL Decanoate 100 mg/ml solution for injection — Current selected SmPCemc · Summary of Product Characteristics
- UK GovernmentUK Government · Reputable Web