Lethal suicide attempt with a mixed-drug intoxication of metoprolol and propafenone - A first pediatric case report

- Metoprolol and propafenone are metabolized by CYP2D6, propafenone is an inhibitor of CYP2D6.
- The pediatric case report showing metoprolol and propafenone intoxication in combination.
- Serum metoprolol, alfa-hydroxymetoprolol and propafenone levels are documented.
- Metoprolol toxicity was exacerbated by interaction with propafenone causing CYP2D6 inhibition.
- Negative inotropic effect was due to β-adrenergic and calcium channel blocking activity.

IntroductionThe β1 adrenergic receptor blocker metoprolol is often prescribed together with the antiarrhythmic drug propafenone. Both are metabolized by cytochrome P450 2D6 and propafenone is also an inhibitor of this enzyme. We present a pediatric case showing metoprolol and propafenone intoxication in combination.CaseA 14-year-old girl was admitted to a local emergency department after ingestion of metoprolol (probably 1 g) and propafenone (probably 1.5-3 g) in a suicide attempt. She developed cardiogenic shock with cardiac arrest and was fully resuscitated. Veno-arterial femorofemoral extracorporeal membrane oxygenation was started immediately. High serum levels of both drugs were detected approximately 10 h after ingestion (2630 ng/mL metoprolol and 2500 ng/mL propafenone). Other serial samples for the monitoring of the levels of metoprolol and its metabolite alfa-hydroxymetoprolol were obtained between days 2 and 4 after admission. The metoprolol/alfa-hydroxymetoprolol ratio on the 2nd day was 36.1, indicative of a poor metabolizer phenotype. The elimination half-life of metoprolol was prolonged to 13.2 h and the clearance decreased by about 70%. The patient condition gradually worsened, brain edema and intracerebral hemorrhage occurred, and on the 6th day, the patient died.ConclusionWe document a pediatric case report of death due to a mixed drug overdose of metoprolol and propafenone, along with data regarding serum metoprolol, alfa-hydroxymetoprolol, and propafenone levels.