Digitalis Toxicity: Mechanisms, Diagnosis, and Management

Digitalis glycosides have a narrow margin between therapeutic and toxic levels. Although the incidence of digitalis toxicity appears to be decreasing, continuation of digoxin therapy in the face of overt toxicity carries a substantial risk of life-threatening cardiac rhythm disturbances. This review will focus primarily on toxicity produced by digoxin and discuss the mechanisms, clinical manifestations, and current management of digitalis toxicity. The appropriate methodology for measurement and interpretation of serum digoxin levels is emphasized. The varied cardiac dysrhythmias induced by digoxin are detailed and their specific management outlined. Immunological (antibody) treatment has now been established and approved for the therapy of advanced, life-threatening digitalis toxicity and the multicenter trial of digitalis antibodies is described. Proper understanding of the pharmacokinetics of digitalis glycosides and careful followup of digitalis treated patients for early evidence of toxicity should help to decrease further the prevalence of toxic reactions.