[Severe digoxin poisoning a case study]

Abstract

Digitalis glycosides are among the oldest drugs used in cardiology. Nowadays, due to the limited indications for their use (advanced heart failure, usually concomitant with atrial fibrillation), cases of poisoning induced by this class of drugs are rarely observed. Digoxin produces a positive inotropic and bathmotropic effect on the heart, but has a negative chronotropic and dromotropic effect. Cardiac glycosides have a narrow therapeutic window, so digitalis treatment can easily lead to symptoms of overdose. In patients taking digoxin, the drug therapeutic level should be maintained at 1-2 ng/ml; the toxic effects occur at concentrations > 2.8 ng/ml and are mainly related to disturbances of cardiac function and of the circulatory system, as well as gastrointestinal symptoms and CNS disturbances. We present, a 45-years-old patient who was hospitalized following the ingestion with suicidal intent of 100 0.25 mg tablets of digoxin. In spite of rapidly applied gastric irrigation and administration of activated charcoal, the drug level in the patient's blood was estimated at 12.0 ng/ml. During her stay on the ward, typical symptoms of severe poisoning were observed: from gastric symptoms (severe nausea, vomiting) to numerous severe arrhythmias and conduction disturbances. Type I, II and III AV blocks were detected, as well as numerous ventricular and supraventricular extrasystoles. These conduction disorders required the use of temporary endocardial pacing. Due to the unavailability of specific antidotes (antidigitalis antibodies) and lack of efficient methods of extracorporeal elimination of the drug, symptomatic treatment comprising the correction of electrolyte disturbances and heart rate control remains the most effective.