Digoxin immune fab

Background

• 1 Fab vial binds 0.5mg of digoxin
• Clinical improvement usually seen within 1hr
• May give as IV bolus in cardiac arrest; otherwise give over 30min

Indications

• Ventricular dysrhythmias
• Hemodynamically significant bradyarrhythmias unresponsive to standard therapy
• Hyperkalemia > 5.5 associated with toxic digoxin level or presumptive diagnosis of overdose
• Also consider for:
  • Pacemaker (may mask cardiac dysrhythmia)
  • Dig level > 10 in acute ingestion
  • Dig level > 4 in chronic ingestion
  • If adult acutely ingests > 10mg
  • If child acutely ingests > 4mg

Side Effects

• Withdrawal of dig effect:
  • CHF, A-fib with RVR
• Hypokalemia

How To Use

• Neither amount ingested nor digoxin level are known:
  • Adult dose
    • 10 vials over 30 min; repeat dose if clinical response is inadequate
  • Peds dose
    • 5 vials over 30 min; repeat dose if clinical response is inadequate
• Amount ingested is known but digoxin level is unknown
  • Calculate total body load (TBL)
    • TBL = Dose (in mg) ingested x 0.8
  • Calculate number of vials needed
    • Number of vials = TBL X 2 (round up to nearest whole number)
• Steady state digoxin level is known
  • Number of vials = (dig level (in ng/mL) X patient wt) / 100
• Chronic toxicity without severe signs
  • Give half the recommended dose
    • Otherwise may unmask the condition for which the patient is taking digoxin
• Cardiac Arrest
  • 20 vials administered undiluted by IV bolus

See Also

• Digoxin Toxicity

References

• 2019 American Geriatrics Society Beers Criteria Update Expert Panel. American Geriatrics Society 2019 Updated AGS Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. J Am Geriatr Soc. 2019;67(4):674-694. doi: 10.1111/jgs.15767 [PubMed 30693946]
• Alsaied T, Baskar S, Fares M, et al. First-line antiarrhythmic transplacental treatment for fetal tachyarrhythmia: a systematic review and meta-analysis. J Am Heart Assoc. 2017;6(12). pii: e007164. doi: 10.1161/JAHA.117.007164. [PubMed 29246961]
• Anderson PO, Sauberan JB. Modeling drug passage into human milk. Clin Pharmacol Ther. 2016;100(1):42-52. doi: 10.1002/cpt.377. [PubMed 27060684]10.1002/cpt.377
• Aronoff GR, Bennett WM, Berns JS, et al. Drug Prescribing in Renal Failure: Dosing Guidelines for Adults and Children. 5th ed. Philadelphia, PA: American College of Physicians; 2007:42.
• Azancot-Benisty A, Jacqz-Aigrain E, Guirgis NM, Decrepy A, Oury JF, Blot P. Clinical and pharmacologic study of fetal supraventricular tachyarrhythmias. J Pediatr. 1992;121(4):608-613. [PubMed 1403399]
• Bakir M, Bilgiç A. Single daily dose of digoxin for maintenance therapy of infants and children with cardiac disease: is it reliable? Pediatr Cardiol. 1994;15(5):229-232. [PubMed 7997427]
• Bendayan R, McKenzie MW. Digoxin pharmacokinetics and dosage requirements in pediatric patients. Clin Pharm. 1983;2(3):224-235. [PubMed 6349908]
• Burk O, Brenner SS, Hofmann U, et al. The Impact of Thyroid Disease on the regulation, expression, and function of ABCB1 (MDRa/P-glycoprotein) and consequences for the disposition of digoxin. Clin Pharm Ther. 2010;88(5):685-694. [PubMed 20844484]
• Cheng JW, Rybak I. Use of digoxin for heart failure and atrial fibrillation in elderly patients. Am J Geriatr Pharmacother. 2010;8(5):419-427. [PubMed 21335295]
• Colucci WS, Sylvia L. Use of digoxin in heart failure with reduced ejection fraction. Post TW, ed. UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com. Accessed October 22, 2018.