Digoxin immune fab
|Trade names||Digibind, DigiFab, others|
|Other names||Digoxin-specific antibody|
|Main uses||Digoxin toxicity|
|Side effects||Low potassium, heart failure, allergic reaction|
|IV infusion, injection|
|Onset of action||30 min|
|Duration of action||15 to 20 hrs|
|Elimination half-life||15 hours for DigiFab, 23 hours for Digibind|
|Chemical and physical data|
|Molar mass||47301.88 g·mol−1|
|(what is this?)|
Digoxin immune fab, sold under the brand name Digibind among others, is the antidote for digoxin toxicity. It may also be used for toxicity from certain plants such as oleander or foxglove and for eclampsia. It is given by injection into a vein. Benefits occur within 30 minutes.
Common side effects include low potassium and heart failure. Other side effects may include allergic reactions including anaphylaxis. When needed, it can be used during pregnancy or breastfeeding. It works by binding to digoxin and similar compounds in the blood.
Digoxin immune fab was approved for medical use in the United States in 1986. In the United Kingdom one 40 mg vial cost the NHS about £750. In the United States this amount costs about 4,200 USD as of 2021. It is made from antibodies from sheep that have been immunized with a digoxin derivative.
- Hemodynamically unstable arrhythmia
- End organ damage
- digoxin level > 4 ng/ml if chronic ingestion
- digoxin level > 10 ng/ml if acute ingestion
- potassium > 5 mEq/L and symptomatic
The dose depends on how much digoxin needs to be removed and the brand of medication. A vial of DigiFab (40 mg) will remove about 0.5 mg of digoxin. In acute toxicity the number of vials needed typically varies from 5 to 20 in adults; though more may be required.
The patient must be closely monitored for anaphylactic shock, and anyone allergic to sheep protein, papain, bromelain, or papaya extracts (papain is used to cleave the antibody into Fab and Fc fragments) should not use ovine digoxin immune fab. Because it is relatively new, no drug interaction studies have been performed yet.
It works by binding to the digoxin, rendering it unable to bind to its action sites on target cells. The complexes accumulate in the blood and are expelled by the kidney.
Society and culture
Price increase were reported from US $380 to US $750 during 2013 in the United States. However, these price increases are not reflective of the United States average AWP for digoxin-Fab as it represents Australian costs converted to US. Prior to 2011, Digibind and DigiFab pricing was US $797 per 38 mg vial and US $786 per 40 mg vial respectively. After GSK discontinued Digibind sale in USA in 2011, the AWP of DigiFab increases by 15% to US $903 per 40 mg vial. AWP of DigiFab has continued to increase as much as 54% occurring in March 2014 to US $2,370 per 40 mg vial. However, the cost may vary depending on wholesaler contractor manufacturer rebates.
Digifab is manufactured and distributed by BTG international Inc. under U.S. License No. 186. DigiFab is a sterile, lyophilized preparation of digoxin-immune ovine Fab (monovalent) immunoglobulin fragments. It is prepared by isolating the immunoglobulin fraction of the ovine serum, digesting it with papain and isolating the digoxin-specific Fab fragments by affinity chromatography. These antibody fragments have a molecular weight of approximately 46,000 Da. Each vial of DigiFab, which will bind approximately 0.5 mg digoxin, contains 40 mg of digoxin immune Fab, 75 mg (approx) of mannitol USP, and 2 mg (approx) sodium acetate USP as a buffering agent. The product contains no preservatives and is intended for intravenous administration.
Digibind is manufactured by GlaxoSmithkline, SpA, Parma Italy under US License No. 129. It’s distributed by GSK, Research Triangle park, NC 27709.
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