Dosing and uses of Digibind, DigiFab (digoxin immune FAB (Antidote))
Adult dosage forms and strengths
powder for injection
- 40mg/vial
Acute Ingestion of Unknown Quantity
Administer 20 vials
Larger dose has faster onset, but may cause febrile reaction; may give 10 vials initially, then at physician's discretion, administer 10 more vials
Each vial of DigiFab (40 mg of Fab) binds 0.5 mg digoxin
Equimolar dose to ingested digoxin (76/80 mg FAB = 1 mg digoxin)
Acute Ingestion of Known Amount
Total digoxin load (mg) divided by 0.5 mg digoxin bound per vial = number of vials to use
Toxicity During Chronic Therapy
Acute distress or for whom a serum digoxin concentration is not available: Administer 6 vials
Renal Impairment
Dose adjustment not necessary but use caution as digoxin immune Fab complex is renally eliminated
Administration
Administer by IV infusion over 15-30 minutes (see IV information)
May be given IVP for life-threatening dysrhythmias
Other Indications & Uses
For life-threatening dysrhythmias or hypotension unresponsive to other measures caused by digoxin, digitoxin or related toxins (ie, foxglove)
[K+] >5 mEq/L in setting of severe digoxin intoxication, especially if increased creatinine
Pediatric dosage forms and strengths
powder for injection
- 40mg/vial
Acute Ingestion of Unknown Quantity
As adults; administer 20 vials
Larger dose has faster onset, but may cause febrile reaction; may give 10 vials initially, then at physician's discretion, administer 10 more vials;
Small children: Monitor for volume overload
Acute Ingestion of Known Amount
As adults; total digoxin load (mg) divided by 0.5 mg digoxin bound per vial = number of vials to use
Toxicity During Chronic Therapy
Infants and small children (<20 kg): Administer 1 viaL
Digibind, DigiFab (digoxin immune FAB (Antidote)) adverse (side) effects
Frequency not defined
Effects (due to w/d of digitalis) include exacerbation of HF, rapid ventricular response in patients with a.fib; posteral hypotension
Falsely increases digoxin concentrations
Hypokalemia
Loss of disease controL
Phlebitis
Fever, May occur with doses above 10 vials
Allergic reactions
Serum sickness
Warnings
Contraindications
Hypersensitivity to sheep proteins
Cautions
Serum digoxin levels rise after digibind treatment - do not use serum levels to guide continuing treatment
Hypokalemia may occur from shifting of extracellular potassium to intracellular space; monitor closely
Patients with heart failure may experience symptom exacerbation due to reduction in digoxin serum concentration
Caution in patients with renal failure
Pregnancy and lactation
Pregnancy category: C
Lactation: excretion in milk unknown; use with caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Digibind, DigiFab (digoxin immune FAB (Antidote))
Mechanism of action
Antibody binds digoxin or other cardiac glycosides and it is then excreted by the kidneys and removed from the body
Pharmacokinetics
Onset of action: ≤ 30 min (observed improvement)
Vd: 0.3 L/kg
Half-life elimination: 15-20 hr (prolonged in renal impairment)
Excretion: Urine (amounts undetectable within 5-7 days)
Administration
IV Preparation
Reconstitute with 4 mL SWI to obtain a 9.5 mg/mL Digibind solution or 10 mg/mL DigiFab soln
For infusion further dilute with NS to desired volume
If very small doses are necessary (<3 mg), may dilute with NS to 1 mg/mL
IV Administration
Infuse over 15-30 min
Digibind is administered using 0.22 micron inline filter; DigiFab should NOT be administered through filter
May be given as rapid IVP if cardiac arrest is imminent (generally not recommended due to increased adverse reactions)
