Published: May 2009

Cardiac risks associated with flecainide

Prescriber Update 30(2): 13
May 2009

Prescribers are reminded of the risk of inducing 1:1 atrioventricular conduction, with a consequent paradoxical increase in ventricular rate, when flecainide (Tambocor™) is used to treat atrial flutter. This reaction is more likely to occur with the use of intravenous flecainide. Consultation with a specialist prior to use of flecainide in emergency situations is recommended.

Flecainide is a class I anti-arrhythmic agent, indicated only in patients without structural heart disease for the prevention, rapid control, or short-term prophylaxis of supraventricular and ventricular arrhythmias. The specific indications are listed in the New Zealand Tambocor™ data sheet, available on the Medsafe website. Please note that flecainide is not recommended for use in patients with chronic atrial fibrillation.

As with other class I anti-arrhythmic agents, there have been reports of patients treated with flecainide for tachycardia due to atrial flutter who have developed a paradoxical increase in the ventricular rate. This increase has been attributed to the induction of 1:1 atrioventricular conduction following the slowing of the atrial rate. A paradoxical increase in the ventricular rate may also occur in patients with atrial fibrillation who receive flecainide. Concomitant negative chronotropic therapy such as digoxin or betablockers may lower the risk of this complication, however the additive negative inotropic effects of flecainide and beta-blockers would suggest that this combination should be used under specialist supervision.

This is a timely reminder to consider the potential risk of cardiac adverse events associated with the use of flecainide. The New Zealand data sheet for Tambocor™ has recently been updated with further information regarding the cardiovascular and pro-arrhythmic adverse effects associated with flecainide.