The prevention and reversal of digoxin intoxication with specific antibodies.

The formation of digoxin-specific antibodies was induced in sheep by immunization with a digoxin-albumin conjugate. The efficacy of the antibodies was investigated in anesthetized cats. When the digoxin-specific antibodies were administered prophylactically as a gammaglobulin, IgG or F (ab')2 preparation, the dose of digoxin needed to induce ventricular dysrhythmia was significantly greater (p less than 0.001) for the pretreated animals than for the controls. To investigate therapeutic efficacy, the animals were digitalized with digoxin over a period of three days and were given digoxin injections on the fourth day to provoke ventricular tachycardia. Of the control animals, three died before two hours had elapsed and the arrhythmia persisted in the two remaining animals. By contrast, a stable sinus rhythm was restored in all animals which were treated with F (ab')2 fragment of the digoxin-specific antibodies after onset of ventricular tachycardia. The doses of digoxin required to trigger renewed ventricular dysrhythmia in these animals were greater than those required at the start of the experiment. The potential clinical use of digoxin-specific antibodies is discussed in the light of these results and reports in the literature.