Flecainide acetate

How it works

It potently blocks cardiac sodium channels, slowing conduction velocity (phase 0 depolarisation) across atrial, ventricular and accessory-pathway tissue, thereby suppressing re-entrant arrhythmias.

Prescribing in practice

• It is contraindicated after myocardial infarction and in significant structural or ischaemic heart disease or impaired left ventricular function because of a proven risk of proarrhythmia and increased mortality.
• In atrial flutter or AF it can organise the rhythm and allow rapid 1:1 AV conduction, so co-prescription of an AV-nodal blocking agent is generally advised.
• It is negatively inotropic and its clearance is reduced in renal or hepatic impairment, requiring caution and dose review.

Monitoring

Monitor ECG for QRS widening and proarrhythmia, with plasma-level checks in renal impairment or where toxicity is suspected.

Counselling the patient

• Report palpitations, blackouts or new dizziness, which may signal a rhythm problem.
• Take the dose consistently and do not stop suddenly without advice.
• Tell any clinician you take this if your heart is checked or you start new medicines.

Evidence & guidelines

Following the CAST trial, class Ic agents like flecainide are avoided after myocardial infarction and in structural heart disease.