Answer
Promazine hydrochloride may prolong the QT interval, and persistently prolonged QT intervals may increase the risk of malignant arrhythmias.
Sources for this answer
- Promazine Hydrochloride 25mg/5ml Oral SyrupRosemont Pharmaceuticals Limited · emc · SmPC §4.4 Special warnings and precautions for use · Version 12Document updated
Sources checked