Adverse Events Associated with Use of Digoxin Immune Fab Reported to the US Food and Drug Administration Adverse Event Reporting System, 1986-2019

Background Digoxin immune fab products, DigiBind and DigiFab, are antidotes for the treatment of patients with life-threatening or potentially life-threatening digoxin toxicity or overdose. Although approved by the US Food and Drug Administration (FDA) in 1986 (DigiBind) and 2001 (DigiFab), there remains a paucity of literature describing the safety of these products in the postmarketing setting. Objective We sought to assess US adverse event (AE) reports submitted to the FDA Adverse Event Reporting System (FAERS) for DigiBind and DigiFab in the postmarketing period. Patients and Methods We searched reports for DigiBind and DigiFab submitted from the time of each product approval through December 31, 2019. Descriptive statistics were used to assess AE reports for DigiBind and DigiFab. Empirical Bayes geometric means (EBGMs) and their 90% confidence intervals were computed to identify disproportionate (i.e., at least twice the expected) reporting of DigiBind and DigiFab. Reports describing selected AEs and death outcomes were individually reviewed. Results A total of 78 DigiBind and 43 DigiFab reports were identified, of which 68 DigiBind (87.2%) and 27 DigiFab (62.8%) reports were serious. Among the most frequently reported AEs for both products [DigiBind, DigiFab, respectively] were cardiac (bradycardia [3.8%, 3.9%], cardiac arrest [3.3%, 3.9%], and hypotension [2.4%, 2.6%]) and non-cardiac (nausea [1.9%, 2.6%] and hyperkalemia [1.4%, 1.9%]) events. These AEs were labeled events or confounded by indication for use (digoxin toxicity). Nineteen (24.4%) DigiBind and 13 (30.2%) DigiFab reports described an outcome of death, of which seven (53.8%) DigiFab reports were attributed to poisoning with non-digoxin cardiac glycosides. No deaths could be attributed to DigiBind or DigiFab administration. Conclusions Our analysis did not identify new safety concerns for DigiBind or DigiFab. Most AEs reported were labeled events or confounded by indication for use.