Digoxin-Specific Antibody Fragment Dosing: A Case Series.

Digoxin-specific antibody fragments (DSFab) are used for the treatment of poisoning by cardiac glycosides, such as pharmaceutical digoxin. Dosing of this therapy for chronic and acute poisonings is based on the steady-state serum concentrations of digoxin, historical data in acute ingestions, or empiric regimens purportedly based on the average requirements. Empiric dosing for adult patients involves utilization of 3-6 vials for chronic poisoning and 10-20 vials for acute poisoning. The aim of this study was to describe the average dosing requirements based on the steady-state serum concentration of digoxin or historical data and compare this with the empiric dosing regimens. We performed a retrospective analysis of cases over an 11-year period presented to the Illinois Poison Center where administration of DSFab was recommended. We identified 140 cases of chronic digoxin poisoning and 26 cases or acute digoxin poisoning for analysis. The average dose of DSFab recommended in the cases of chronic digoxin poisoning was 3.05 vials (SD ± 1.31). The average dose of DSFab recommended in the cases of acute digoxin poisoning was 6.33 vials (SD ± 5.26). These values suggest that empiric dosing regimens may overestimate the need for DSFab in cases of both chronic and acute poisonings of pharmaceutical digoxin.