Introduction : Flecainide, a class 1 c antiarrhythmic, is used to treat supraventricular tachycardias. Sodium bicarbonate (bicarb) is used in overdose (OD) treatment. Intravenous fat emulsion (IFE) is an uncommon/ unreported treatment for flecainide OD. We report a case of a life-threatening flecainide OD, treated with IFE, with serum drug levels pre/post IFE administration.
Case report : A 51-year-old man ingested 2 g of flecainide, and presented to the ED 90 min post-ingestion (PI). He had HR 44 and BP 140 systolic (SBP). ECG showed sinus rhythm, QRS 162 ms and QTc 427 ms. Within 45 min his HR was 40 and SBP 60; a repeat ECG showed 1° AV block with QRS 150 ms and QTc 524 ms. He had already received 1 L normal saline (NS), 100 mEq bicarb and activated charcoal. Over the next hour in the ED he received another 1 L NS, 100 mEq bicarb, 1 mg atropine, 2 g Mg, and a 100 mL bolus of 20% IFE. He was admitted to the ICU with HR 55 and SBP 90. Five hours into his ICU stay the bicarb infusion was stopped, he had received a 1 L infusion of 20% IFE, and his HR/BP QRS/QTc had all normalized. He went to psychiatry on day 5 with no end-organ effects. Flecainide levels were 1.8 mcg/mL (nml 0.2–1.0) 100 min PI (pre-IFE), 2.76 mcg/mL 7 h PI (post-IFE), and 0.27 mcg/mL 3.5 days PI.
Discussion : This case is unique in that the patient received IFE for a flecainide OD, and drug levels are reported. The AV block, ¡ýHR, ¡ýBP, and ¡üQRS/QTC are all expected from this OD; they occur due to Na+- channel blockade, but also K+-channel blockade. The bicarb, NS, and Mg are standard, but the IFE is not. Flecainide has a similar profile to drugs for which IFE has been used successfully for OD. It has a high Vd (10 L/kg) and a high log P octanol/water coefficient (3.8). The standard therapy and IFE helped normalize the patient’s hemodynamics and cardiac conduction. No conclusion can be drawn from the serum levels, other than they were high. The initial level may have been before the serum peak, which can occur as late as 6 h PI. The first post-IFE level is not interpreted easily because not enough is known about drug levels after IFE administration.
Conclusion : We present a case of a life-threatening flecainide overdose successfully treated with standard therapy and intravenous fat emulsion bolus and infusion.