Core pharmacology

Class Group

Antiarrhythmic –
Vaughan Williams Class Ic
Na channel blocker

Legacy Cicm Level

Level 3

Introduction

Amide local anaesthetic
Class IC antiarrhythmic
Na channel blocker

Indications Uses

1. for the suppression of irritable foci, e.g. ventricular tachycardia and
ventricular ectopics
2. in the treatment of re-entry dysrhythmias, e.g. the
Wolff–Parkinson–White syndrome and
3. in the treatment of symptomatic paroxysmal atrial fibrillation intolerant
of other medication.

Presentation

As 50/100 mg tablets and as a 10 mg/ml solution of flecainide acetate for intravenous administration

Mechanism of action

Flecainide reduces the maximum rate of depolarization in heart muscle and thereby slows conduction, particularly in the
His–Purkinje system. It has a profound effect on conduction in accessory
pathways, especially on retrograde conduction, and markedly suppresses
ventricular ectopic foci. It is a local anaesthetic agent which depresses membrane responsiveness and conduction velocity, with no effect on the duration of the action potential.

Physiological effects

CVS
Flecainide is generally well tolerated; the blood pressure and heart rate
usually remain unchanged. The drug has negative inotropic potential.

CNS
Visual disturbances may occur and are probably a central effect of
the drug

Adverse Effects Toxicity

Reversible liver damage, dizziness, paraesthesiae,
headaches, and nausea may complicate the use of the drug.

Absorption

PO. Rapidly absorbed.
BA 85-90%

Protein binding

37-58%

Volume of distribution

5.8-10 L/kg

Metabolism

Liver
2 metabolites: metao-dealkylated flecainide and its lactam

Excretion

Urine (10-50% unchanged)

Half-life

IV: 7-15hrs
PO: 12-27hrs

Route And Dose

PO 100-200mg Q12hrly
IV: Bolus 2mg/kg over 10min → Infusion 1.5mg/kg/hr for 1hr → 0.25 mg/kg/hr