A. Emergency and Supportive Measures
After acute ingestion, administer activated charcoal. Monitor potassium levels and cardiac rhythm closely. Treat bradycardia initially with atropine (0.5–2 mg intravenously) or a transcutaneous external cardiac pacemaker.
For patients with significant intoxication, administer digoxin-specific antibodies (digoxin immune Fab [ovine]; DigiFab). Estimation of the dose is based on the body burden of digoxin calculated from the ingested dose or the steady-state serum digoxin concentration, as described below. More effective binding of digoxin may be achieved if the dose is given partly as a bolus and the remainder as an infusion over a few hours.
1. From the ingested dose
Number of vials = approximately 1.5–2 × ingested dose (mg).
2. From the serum concentration
Number of vials = serum digoxin (ng/mL) × body weight (kg) × 10–2. Note: This is based on the equilibrium digoxin level; after acute overdose, serum levels may be falsely high for several hours before tissue distribution is complete, and overestimation of the DigiFab dose is likely.
Empiric titration of DigiFab may be used if the patient’s condition is relatively stable and an underlying condition (eg, atrial fibrillation) favors retaining a residual level of digitalis activity. Start with one or two vials and reassess the patient’s clinical condition after 20–30 minutes. For cardiac glycosides other than digoxin or digitoxin, there is no formula for estimation of vials needed and treatment is entirely based on response to empiric dosing.
Note: After administration of digoxin-specific Fab antibody fragments, serum digoxin levels may be falsely elevated depending on the assay technique.
et al. Elderly patients with suspected chronic digoxin
toxicity: a comparison of clinical characteristics of patients receiving and not receiving digoxin-Fab. Emerg Med Australas. 2018 Apr;30(2):242–8.