Circulation
Treatment for hypotension
For hypotension due to flecainide poisoning, first-line treatment is intravenous fluid resuscitation. If hypotension persists, start inotropic support with adrenaline (epinephrine). Do not use other inotropes without consulting a clinical toxicologist.
Treatment for QRS widening and sodium channel blockade: serum alkalinisation
Commence continuous ECG monitoring and assess 2-hourly 12-lead ECGs for at least 6 hours to detect QRS widening in all patients with flecainide poisoning.
Treat ventricular arrhythmias associated with QRS widening with serum alkalinisation (intravenous sodium bicarbonate) and concurrent hyperventilation therapy (by intubation and mechanical ventilation).
For serum alkalinisation, in adults and children, use:
sodium bicarbonate 8.4% 1 to 2 mL/kg up to 100 mL (1 to 2 mmol/kg up to 100 mmol) intravenously, every 3 to 5 minutes, titrated to a narrowing of the QRS complex and aiming for a serum pH between 7.45 and 7.55. Maximum total dose is 6 mL/kg (6 mmol/kg). Urgently seek advice from a clinical toxicologist if there is inadequate response to the maximum total dose flecainide poisoning
PLUS
hyperventilation by intubation and mechanical ventilation, aiming for a serum pH between 7.45 and 7.55 (typically by maintaining partial pressure of arterial carbon dioxide [PaCO2] between 30 and 35 mmHg).
Serum alkalinisation can cause hypokalaemia due to intracellular potassium shift—monitor the serum potassium concentration and replace potassium if required, aiming for the normal serum potassium concentration.
For more information on the management of QRS widening due to drug poisoning, see Treatment for QRS widening and sodium channel blockade: serum alkalinisation).
If there is inadequate response to serum alkalinisation, consider lidocaine and urgently seek advice from a clinical toxicologist.
Treatment for other arrhythmias
Commence continuous ECG monitoring and 2-hourly 12-lead ECGs for at least 6 hours in all patients with flecainide poisoning.
Although QT-interval prolongation occurs in flecainide poisoning, torsades de pointes is rare. If there is evidence of QT-interval prolongation on ECG, manage urgently according to Treatment for QT-interval prolongation and torsades de pointes.
For cardiorespiratory arrest and life-threatening arrhythmias, follow advanced life support protocols1 and seek advice from a clinical toxicologist.
Extracorporeal membrane oxygenation
Extracorporeal membrane oxygenation (ECMO) may be beneficial in severe flecainide poisoning unresponsive to serum alkalinisation and inotropic therapy. Discuss this with a clinical toxicologist.