Initial symptoms may be non-specific such as dizziness or fatigue. This can progress to bradyarrhythmias, atrioventricular blocks and profound hypotension. In severe cases this may result in myocardial ischaemia, cardiogenic shock, thrombo-embolic events and death.
Following ingestion of immediate release preparations, signs and symptoms usually appear within 3-6 hours with modified release preparations taking up to 16 hours.
