Free and Total Digoxin in Serum During Treatment of Acute Digoxin Poisoning With Fab Fragments: Case Study

Abstract

A woman ingested 10 mg of methyldigoxin in a suicide attempt and presented 19 hours after ingestion with clinical signs of glycoside intoxication. Her serum level of digoxin was 7.4 ng/mL, and antidotal therapy with Fab antibody fragments was started. The manufacturer's recommended dosing scheme was modified, with 80 mg Fab administered intravenously within 15 minutes followed by a continuous infusion at 30 mg/h. Total serum concentration of digoxin increased markedly within minutes after Fab therapy was started, while the level of free digoxin immediately decreased into the nontoxic range without recrudescent toxic effects of digoxin. The cumulative amounts of free and bound digoxin that were excreted in urine within 30 hours after ingestion were 900 µg and 1600 µg, respectively. Half-life of bound digoxin in urine was 9.9 hours; mean rate of clearance of bound digoxin in the urine was 7.0 mL/min. On the basis of these kinetic data, a smaller initial bolus dose of Fab followed by a continuous infusion may be a more tailored, cost-effective, and relatively safe therapy for patients who have overdosed on cardiac glycosides.

Electrocardiographic Changes After Suicidal Digoxin Intoxication in a Healthy Woman

“…Although suicide with massive digoxin overdose is an exceedingly rare event, there are several cases reported in the literature [4, 5]. In this setting antidigoxin Fab fragments are recommended, as they seem to be safe and effective.…”

“…However, this strategy is certainly expensive and it has not been supported by clinical trials. Furthermore, the dosage regimen to achieve optimal binding of Fab to digoxin remain to be determined [5]. …”

High dose digoxin intoxication: Case report and literatures evaluation

“…Bu nedenle mutlak ritim monitörizasyonu planlanmalıdır. Eyer ve arkadaşları 6 , ilaç alınımdan 19 saat sonra bakılan kan digoksin düzeyi 7.4 ng/mL ve EKG'de bradikardi ile STsegment depresyonu olan hastaya, başta düşük dozda bolus sonra idame infüzyonla Fab antikoru vererek tedavi etmişler. Fab antikor tedavinin 4. saatinden itibaren EKG bulgularının normale döndüğü bildirilmiştir.…”

Interferences in Therapeutic Drug Monitoring

“…Her symptoms of digoxin toxicity (electrocardiogram) as well as nausea and vomiting resolved within three hours of initiation of therapy, and the patient was discharged from the hospital after three days [8]. Methyldigoxin is a semisynthetic cardiac glycoside which is rapidly converted into digoxin after oral administration.…”