Gastrointestinal dialysis of digoxin using cholestyramine

Cardiac glycoside toxicity: more than 200 years and counting

Digitalis toxicity produces a toxidrome characterized by gastrointestinal, neurologic, electrolyte, and nonspecific cardiac manifestations. Chronic toxicity remains much more difficult to recognize compared with an acute presentation because of the nonspecific manifestations; therefore, serum glycoside levels are essential for diagnosis in this population. The mainstay of management continues to be rapid toxidrome identification followed by digoxin-specific antibody fragment therapy with supportive care. Several controversies still remain, including therapy for patients dependent on hemodialysis, appropriateness of calcium therapy for hyperkalemia, ideal agents for arrhythmia therapy, and the potential utility of plasmapheresis for removal of bound digoxin-antibody fragment complexes.

Mechanisms, manifestations, and management of digoxin toxicity in the modern era

Because of the common use of digoxin and because of its narrow therapeutic index, digoxin toxicity has been prevalent historically and, therefore, most clinicians are well aware of the classical dose/concentration-related signs and symptoms of toxicity. Yet, in the modern era the incidence of digoxin toxicity has been declining for a variety of reasons, including a new (lower) therapeutic range, the development of more effective drug therapies for heart failure, and more accurate dosing methods. In addition, digoxin toxicity, once commonly fatal, can now be quickly and effectively treated by the emergency administration of antidigoxin Fab fragments. Indeed, it may be possible to expand the use of Fab fragments to select patients with non-life-threatening digoxin toxicity, in order to save costs and improve patient comfort. Most cases of digoxin toxicity are caused by inappropriately high dosages, which are usually prescribed in the setting of renal dysfunction, while other cases can be attributed to system errors such as multiple prescriptions, poor patient counseling, or errors in transcribing. With modern computerized prescribing systems, such as direct physician order entry and prompts that alert the clinician to the potential for error, it is possible to decrease the incidence of digoxin toxicity even further. A realistic goal is to nearly eradicate once commonplace digoxin toxicity or at least make its occurrence a rare event.