Flecainide toxicity with pill-in-pocket approach from accidental overdose: a case report

The Pill-in-the-Pocket (PiP) approach may be used in highly selected patients to achieve acute pharmacological cardioversion into sinus rhythm. Flecainide toxicity is rarely reported, especially with patients who take flecainide as PiP, and only limited evidence exists in its management. We present a case of accidental flecainide overdose for a patient who is on PiP and the acute management strategy.

A 78-year-old female with persistent atrial fibrillation (AF), previously underwent pulmonary vein isolation and maintained on verapamil 240 mg twice daily, presented to the electrophysiology clinic following a recent hospital admission for recurrent AF. Due to infrequent recurrent episodes of symptomatic AF, the patient preferred to avoid both repeat ablation and additional daily medications. After an initial trial on telemetric monitoring, a PiP approach with flecainide 300 mg was adopted. Unfortunately, palpitations and dyspnoea in the context of chronic obstructive pulmonary disease exacerbation led the patient to self-medicate with multiple doses of albuterol and flecainide. Twelve-lead electrocardiogram showed slow AF with a wide QRS complex. The patient received 1 g of calcium gluconate with a 180 mEq bolus of sodium bicarbonate 8.4% and was started on continuous sodium bicarbonate infusion at 150 mL/h. Over a 12 h period, the QRS complex narrowed down, and the rhythm returned to normal sinus rhythm with a QRS interval of 136 ms.

The PiP strategy with flecainide is safe and effective. Reinforcement of medication dosing and frequency with patient read back is key to avoid accidental toxicity, which could be life-threatening. Treatment with sodium bicarbonate is quick and highly effective.