DIGIFab

Preparation and
Administration of DIGIFab1

Use and Storage

  • Each vial of DIGIFab contains 40 mg of digoxin immune Fab protein and is 
    intended for one-time use only.
  • The reconstituted product should be used promptly. If not used immediately,
    store under refrigeration at 2° to 8°C (36° to 46°F) for up to 4 hours.

Reconstitution

digifab-administration-reconstitute-image
1

Reconstitute each vial of DIGIFab with 4 mL Sterile
Water for Injection USP.

digifab-administration-mix-image
2

Gently mix to obtain a solution containing approximately
10 mg/mL digoxin immune Fab protein.

digifab-administration-injection-image
digifab-administration-injection-image
3

Add the reconstituted product to an appropriate
volume of 0.9% sodium chloride for injection.

digifab-administration-inspect-image

Infants and Small Children

  • For infants and small children who may require very small doses, reconstitute the 40 mg as directed and administer undiluted using a tuberculin syringe.
  • For very small doses, dilute a reconstituted vial with an additional 36 mL of isotonic saline to achieve a concentration of 1 mg/mL.

Infusion

Administer slowly as an intravenous infusion over at least 30 minutes. If infusion rate–related reactions occur (eg, hypotension, wheezing, urticaria), the infusion should be stopped and restarted at a slower rate.

If cardiac arrest is imminent, DIGIFab can be given by bolus injection. With bolus injection, an increased incidence of infusion-related reactions may be expected.

General Precautions1

  • Serious digoxin toxicity can cause hyperkalemia; administration of potassium supplements in these patients may be hazardous. After treatment with DIGIFab, serum potassium concentration may decrease rapidly and must be monitored frequently, especially during the first several hours after administration.
  • The clinical condition of patients with poor cardiac function may deteriorate secondary to the withdrawal of the inotropic action of digoxin by DIGIFab. If needed, additional support can be provided by using other intravenous inotropes such as dopamine, dobutamine, or vasodilators.
  • Care must be taken not to aggravate digoxin-induced rhythm disturbances. Restoration of digoxin therapy should be postponed, if possible, until Fab fragments have been eliminated from the body, which may require several days; patients with impaired renal function may require 1 week or longer.

References

  1. DIGIFab Digoxin Immune Fab (ovine) [package insert]. West Conshohocken, PA: BTG International Inc.; 2017.
  2. Dart RC, Goldfrank LR, Erstad BL, et al. Expert consensus guidelines for stocking of antidotes in hospitals that provide emergency care. Ann Emerg Med. 2018;71(3):314-325.


INDICATIONS AND USAGE

DIGIFab is indicated for the treatment of patients with life-threatening or potentially life-threatening digoxin toxicity or overdose, including:

  • Known suicidal or accidental consumption of fatal doses of digoxin: 10 mg or more of digoxin in healthy adults, or 4 mg (or more than 0.1 mg/kg) in healthy children, or ingestion of an amount that can cause steady state serum concentrations of ≥10 ng/mL;
  • Chronic ingestions causing steady-state serum digoxin concentrations >6 ng/mL in adults or 4 ng/mL in children;
  • Manifestations of life-threatening toxicity of digoxin overdose such as severe ventricular arrhythmias, progressive bradycardia, and second or third degree heart block not responsive to atropine, serum potassium levels exceeding 5.5 mEq/L in adults or 6 mEq/L in children with rapidly progressive signs and symptoms of digoxin toxicity.

IMPORTANT SAFETY INFORMATION

Warnings and Precautions

General

Suicidal ingestion may result from more than one drug. Consider toxic effects of other drugs or poisons in cases where signs and symptoms of digitalis toxicity are not relieved by administration of DIGIFab.

Rapid drop in serum potassium concentration may occur after treatment. Monitor frequently.

Patients with poor cardiac function may deteriorate secondary to the withdrawal of the inotropic action of digoxin by DIGIFab. Monitor frequently and provide additional inotropic support if needed. Postpone re-digitalization, if possible, until the Fab fragments have been eliminated; this may require several days or a week or longer in patients with impaired renal function.

Hypersensitivity Reactions

Anaphylaxis and hypersensitivity reactions are possible. Carefully monitor patients for signs and symptoms of an acute allergic reaction and if one occurs, stop the infusion and treat immediately with appropriate emergency medical care.

Patients with known allergies to sheep protein or those who have previously received intact ovine antibodies or Fab are particularly at risk for an anaphylactic reaction.

Do not administer DIGIFab to patients with a known history of hypersensitivity to papaya or papain unless the benefits outweigh the risks and appropriate management for anaphylactic reactions is readily available.

Use of DIGIFab in Renal Failure

The elimination half-life of DIGIFab in renal failure has not been clearly defined. Monitor patients with severe renal failure who receive DIGIFab for a prolonged period for possible recurrence of toxicity. Monitoring of free (unbound) digoxin concentrations after the administration may be appropriate.

Laboratory Tests

DIGIFab may interfere with digitalis immunoassay measurements. Thus, standard serum digoxin concentration measurements may be clinically misleading until the Fab fragments are eliminated from the body. This may take several days or a week or more in patients with markedly impaired renal function. If possible, obtain serum digoxin samples before DIGIFab administration to establish the level of serum digoxin at the time of diagnosis.

The total serum digoxin concentration may rise precipitously following administration of DIGIFab, but this will be almost entirely bound to the Fab fragment and not able to react with receptors in the body.

Adverse Reactions

The most common adverse reactions (>7%) related to DIGIFab administration are worsening congestive heart failure (13%), hypokalemia (13%) and worsening atrial fibrillation (7%).

Please see full Prescribing Information.