Pharm 101: Flecainide

Class

Class IC anti-arrhythmic

Pharmacodynamics

• Potent blocker of Na and K channels with slow unblocking kinetics
• Does not prolong APD, or QT interval
• No antimuscarinic effects
• Very effective in suppressing PVCs

Pharmacokinetics

• Well absorbed orally
• Peak plasma levels at 3 hours
• Half-life 20 hours
• V_d 8L/kg
• Hepatic metabolism
• 30% of single oral dose is excreted unchanged in urine

Clinical uses

• Supraventricular arrhythmias in patients with no cardiac disease
• Usual dose 100-200 mg BD

Adverse effects

• May cause severe exacerbation of arrhythmia when administered to patients with:
  • Preexisting ventricular tachyarrhythmias
  • Previous MI and ventricular ectopy

Precautions/contraindications

• Hypotension
• LV dysfunction

Further reading

• Buttner R. Pharm 101: Antiarrhythmic Agents. LITFL

References

• Katzung BG. Basic and Clinical Pharmacology. 14e. 2018: 242