⚠️ Specialist use only: Flecainide should be initiated and monitored by a cardiologist. It must always be co-administered with an AV nodal blocking agent (e.g. β-blocker, diltiazem) to prevent paradoxical 1:1 atrial flutter conduction.

📖 About

Class Ic antiarrhythmic: potent sodium channel blocker.
CAST trial (1989, NEJM): Use in post-MI patients with LV dysfunction increased arrhythmic death. Now contraindicated in structural heart disease and IHD.
Reserved for patients with structurally normal hearts under specialist care.

⚙️ Mode of Action

Blocks fast inward sodium channels → marked slowing of conduction through atria, AV node, His–Purkinje, and ventricles.
Widened PR, QRS, and (modestly) QT intervals on ECG.
Minimal effect on action potential duration compared with Class Ia drugs.
Negative inotropic effect (caution in impaired LV function).

🩺 Indications

Paroxysmal atrial fibrillation or atrial flutter (in absence of structural heart disease).
AV re-entrant tachycardia (e.g. Wolff–Parkinson–White syndrome).
Other supraventricular tachycardias (SVT) refractory to standard therapy.
Occasionally used in certain ventricular arrhythmias, only under specialist supervision.

💊 Dosing – Flecainide Acetate (BNF – check locally)

Indication	Dose & Notes
⚡ Fast AF (acute)	• 2 mg/kg IV infusion over 30–60 min (max 150 mg) • Requires continuous ECG monitoring
📅 Long-term maintenance	• 50–150 mg PO twice daily (usual ~100 mg BD) • Max 300 mg/day
💊 Pill-in-the-pocket (AF)	• 200–300 mg PO stat • Only if patient has had a prior safe monitored trial

🚫 Contraindications

Structural heart disease (LV dysfunction, IHD, significant LV hypertrophy).
Atrial flutter without AV nodal blocker (risk of 1:1 conduction and fast ventricular response).
Second-/third-degree AV block or sinus node dysfunction (without pacing).
Cardiogenic shock, severe bradycardia.
Concomitant use with other Class I antiarrhythmics.

❗ Side Effects

Dizziness, visual disturbance, metallic taste.
Palpitations, chest pain, dyspnoea.
Proarrhythmia: ventricular tachycardia, ventricular fibrillation, sudden death (esp. in structural heart disease).
Negative inotropy: may precipitate or worsen heart failure.
Ataxia, tremor, confusion (rare).

🔎 Cautions & Monitoring

Baseline ECG and echocardiogram required before initiation.
Serial ECGs to monitor QRS widening (stop if >25% increase from baseline).
Caution in pacemaker/ICD patients (can alter sensing and capture thresholds).
Adjust dose in renal or hepatic impairment.

📚 References

BNF: Flecainide
Summary of Product Characteristics
CAST Trial, NEJM 1989: Mortality with Class Ic post-MI

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Flecainide Acetate 💊