Answer
Erythromycin can prolong cardiac repolarisation and rarely cause serious arrhythmias, especially with existing QT prolongation, electrolyte disturbance or interacting medicines.
Sources for this answer
- UK GovernmentUK Government · Reputable Web
- Erythromycin Ethyl Succinnate 500 mg/5 ml Granules for Oral Suspension 0015 — Current selected SmPCemc · Summary of Product Characteristics