Flecainide is a Class I
antiarrhythmic drug of the local anaesthetic type. It can be given either intravenously or orally and its pharmacokinetic properties allow relatively long (12 hours) dosing intervals with
oral administration. In several open and a few controlled therapeutic trials, orally administered
flecainide has brought about a greater than 90% suppression of
ventricular ectopic beats in about 80% of patients. A similar percentage of patients (83%) experienced at least an 80% suppression of their
ventricular tachycardia in these trials. A slightly greater response rate was reported with
intravenous infusion of
flecainide. Initial results in arrhythmias complicating the
Wolff-Parkinson-White syndrome have been favourable. Comparative trials are few in number but
flecainide has proved to be more effective than
quinidine, and possibly more effective than
disopyramide,
mexiletine,
tocainide and
propafenone, in suppressing ventricular ectopic activity. The most commonly reported extracardiac adverse effects have been
dizziness and visual disturbances. Proarrhythmic effects have been reported in 7 to 8% of patients, with a higher incidence in patients with serious
ventricular tachycardia and reduced myocardial function. The moderate negative inotropic effects of
flecainide can become clinically significant in patients with impaired ventricular function. Thus
flecainide, with its convenient dose schedule and apparently low incidence of serious side effects, would appear to be a useful addition to the antiarrhythmic agents available. Further studies are needed though, to confirm its long term tolerability when used prophylactically.