Massive digitoxin intoxication treated with digoxin-specific antibodies in a child

A 20-month-old girl with massive digitoxin intoxication (initial digitoxin serum level: 629 ng/ml) was successfully treated with digoxin-specific antibody fragments (Fab). She presented with moderate signs of digitalis toxicity (somnolence, bradycardia, first-degree AV block) and improved rapidly during fractional Fab administration. Free serum-digitoxin disappeared after 6 vials of Fab (480 mg), but was measurable again on days 6 and 7. This case demonstrated that digoxin-specific antibodies, despite a 30-100 times lesser affinity for digitoxin, are effective in massive digitoxin intoxications. A rebound phenomenon may occur several days later and should be taken into consideration.