Answer
Overdose can cause marked drowsiness or agitation, hallucinations, anticholinergic symptoms, seizures, abnormal heart rhythms, coma or cardiovascular collapse. Seek urgent medical help and take the packaging.
Sources for this answer
- Benylin Chesty Coughs (Original) — Current selected SmPCemc · Summary of Product Characteristics
- Benylin Children's Night Coughs — Current selected SmPCemc · Summary of Product Characteristics