Cardiogenic shock following a single therapeutic oral dose of verapamil.

Cardiogenic shock and apnoea appeared in a 78-year-old woman with a history of biventricular heart failure, following ingestion of a single 80 mg verapamil tablet. She was resuscitated with artificial ventilation, dobutamine, norepinephrine and calcium gluconate. Toxicological analysis revealed unexpectedly high plasma verapamil concentration, which was attributed to the patient's liver failure. In patients with advanced heart failure a single oral therapeutic dose of verapamil may have a severe toxic effect.