Digoxin Immune FabU.S. Brand Names: Digibind�(r); DigiFab™
Synonyms: Antidigoxin Fab Fragments, Ovine
Generic Available: No
Canadian Brand Names: Digibind�(r)
Use: Treatment of life-threatening or potentially life-threatening digoxin intoxication, including:
acute digoxin ingestion (ie, >10 mg in adults or >4 mg in children)
chronic ingestions leading to steady-state digoxin concentrations > 6 ng/mL in adults or >4 ng/mL in children
manifestations of digoxin toxicity due to overdose (life-threatening ventricular arrhythmias, progressive bradycardia, second- or third-degree heart block not responsive to atropine, serum potassium >5 mEq/L in adults or >6 mEq in children)
Pregnancy Risk Factor: C
Pregnancy Implications: Animal reproduction studies have not been conducted. Safety and efficacy in pregnant women have not been established. Use during pregnancy only if clearly needed.
Lactation: Excretion in breast milk unknown/use caution
Contraindications: Hypersensitivity to sheep products or any component of the formulation
Warnings/Precautions: Suicidal attempts often involve multiple drugs. Consider other drug toxicities as well. Hypersensitivity reactions can occur. Epinephrine should be immediately available. Serum potassium levels should be monitored, especially during the first few hours after administration. Total serum digoxin concentrations will rise precipitously following administration of this drug (has no clinical meaning - avoid monitoring serum concentrations). If digoxin was being used to treat CHF then may see exacerbation of symptoms as digoxin level is reduced. Use with caution in renal failure (experience limited) - the complex will be removed from the body more slowly. Monitor for reoccurrence of digoxin toxicity. Has reversed thrombocytopenia induced by digoxin. Failure of response to adequate treatment may call diagnosis of digitalis toxicity into question. Digoxin immune Fab is processed with papain and may cause hypersensitivity reactions in patients allergic to papaya, other papaya extracts, papain, chymopapain, or the pineapple enzyme bromelain. There may also be cross allergy with dust mite and latex allergens.
Adverse Reactions: Frequency not defined. Cardiovascular: Effects (due to withdrawal of digitalis) include exacerbation of low cardiac output states and CHF, rapid ventricular response in patients with atrial fibrillation; postural hypotension Endocrine & metabolic: Hypokalemia Local: Phlebitis Miscellaneous: Allergic reactions, serum sickness
Overdosage/Toxicology: Symptoms of overdose include delayed serum sickness. Treatment of serum sickness includes acetaminophen, histamine1 and possibly histamine2 blockers, and corticosteroids.
Drug Interactions: Digoxin: Following administration of digoxin immune Fab, serum digoxin levels are markedly increased due to bound complexes (may be clinically misleading, since bound complex cannot interact with receptors).
Stability: Should be refrigerated (2°C to 8°C). Reconstitute by adding 4 mL sterile water, resulting in 10 mg/mL for I.V. infusion. The reconstituted solution may be further diluted with NS to a convenient volume (eg, 1 mg/mL). Reconstituted solutions should be used within 4 hours if refrigerated. For very small doses, vial can be reconstituted by adding an additional 36 mL of sterile isotonic saline, to achieve a final concentration of 1 mg/mL.
Mechanism of Action: Digoxin immune antigen-binding fragments (Fab) are specific antibodies for the treatment of digitalis intoxication in carefully selected patients; binds with molecules of digoxin or digitoxin and then is excreted by the kidneys and removed from the body
Pharmacodynamics/Kinetics: Onset of action: I.V.: Improvement in 2-30 minutes for toxicity Half-life elimination: 15-20 hours; prolonged with renal impairment Excretion: Urine; undetectable amounts within 5-7 days
Dosage: Each vial of Digibind�(r) 38 mg or DigiFab™ 40 mg will bind ~0.5 mg of digoxin or digitoxin. Estimation of the dose is based on the body burden of digitalis. This may be calculated if the amount ingested is known or the postdistribution serum drug level is known (round dose to the nearest whole vial). See table.
Fab dose based on serum drug level postdistribution:: Digoxin Immune Fab| Tablets Ingested | Fab Dose |
(0.25 mg) |
(vials) | | 5 | 2 | | 10 | 4 | | 25 | 10 | | 50 | 20 | | 75 | 30 | | 100 | 40 | | 150 | 60 | | 200 | 80 |
Fab dose based on serum drug level postdistribution: Digoxin: No. of vials = level (ng/mL) x body weight (kg) divided by 100 Digitoxin: No. of vials = digitoxin (ng/mL) x body weight (kg) divided by 1000 If neither amount ingested nor drug level are known, dose empirically as follows: For acute toxicity: 20 vials, administered in 2 divided doses to decrease the possibility of a febrile reaction, and to avoid fluid overload in small children. For chronic toxicity: 6 vials; for infants and small children (
20kg), a single vial may be sufficient
Administration: Continuous I.V. infusion over  30 minutes is preferred. May give by bolus injection if cardiac arrest is imminent. Small doses (infants/small children) may be administered using tuberculin syringe. Stopping the infusion and restarting at a slower rate may help if infusion-related reactions occur.
Monitoring Parameters: Serum potassium, serum digoxin concentration prior to first dose of digoxin immune Fab; digoxin levels will greatly increase with digoxin immune Fab use and are not an accurate determination of body stores; standard digoxin concentration measurements may be misleading until Fab fragments are eliminated from the body. Patients with renal failure should be monitored for a prolonged period for re-intoxication with digoxin following the re-release of bound digoxin into the blood.
Test Interactions: Digoxin immune Fab interferes with digitalis immunoassay test leading to misleading digoxin serum concentrations until the Fab fragments are eliminated from the body. If possible, take digoxin serum levels prior to the administration of digoxin immune Fab; keeping in mind the time the last dose of digoxin was taken.
Patient Education: Patient education and instruction will be determined by patient condition and ability to understand. Immediately report dizziness, palpitations, cramping, respiratory difficulty, rash, or itching. Pregnancy/breast-feeding precautions: Inform prescriber if you are pregnant. Consult prescriber if breast-feeding.
Dental Health: Effects on Dental Treatment: No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions: No information available to require special precautions
Mental Health: Effects on Mental Status: None reported
Mental Health: Effects on Psychiatric Treatment: None reported
Dosage Forms: Injection, powder for reconstitution: Digibind�(r): 38 mg DigiFab™: 40 mg
References: Antman EM, Wenger TL, Butler VP Jr, et al, "Treatment of 150 Cases of Life-Threatening Digitalis Intoxication With Digoxin-Specific Fab Antibody Fragments,"Circulation, 1990, 81(6):1744-52. Aruna AS and Jue SG, "Digoxin Immune Fab Administration Following an Unexplained Increase in Serum Digoxin Concentration,"J Pharm Sci Technol, 1994, 10:246-9. Hickey AR, Wenger TL, Carpenter VP, et al, "Digoxin Immune Fab Therapy in the Management of Digitalis Intoxication: Safety and Efficacy Results of an Observational Surveillance Study,"J Am Coll Cardiol, 1991, 17(3):590-8. Kaufman J, Leikin J, Kendzierski D, et al, "Use of Digoxin Fab Immune Fragments in a Seven-Day-Old Infant,"Pediatr Emerg Care, 1990, 6(2):118-21. Leikin J, Vogel S, Graft J, et al, "Use of Fab Fragments of Digoxin-Specific Antibodies in the Therapy of Massive Digoxin Poisoning,"Ann Emerg Med, 1985, 14(2):175-8. Martiny SS, Phelps SJ, and Massey KL, "Treatment of Severe Digitalis Intoxication With Digoxin-Specific Antibody Fragments, A Clinical Review,"Crit Care Med, 1988, 16(6):629-35. Shumaik GM, Wu AW, and Ping AC, "Oleander Poisoning: Treatment With Digoxin-Specific Fab Antibody Fragments,"Ann Emerg Med, 1988, 17(7):732-5. Ujhelyi MR and Robert S, "Pharmacokinetic Aspects of Digoxin-Specific Fab Therapy in the Management of Digitalis Toxicity,"Clin Pharmacokinet, 1995, 28(6):483-93. Varriale P and Mossavi A, "Rapid Reversal of Digitalis Delirium Using Digoxin Immune Fab Therapy,"Clin Cardiol, 1995, 18(6):351-2.
International Brand Names: Digibind�(r) (CA)
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