Dosing and Administration

Dose and Administer CroFab® Appropriately to Gain and Continue Control of Envenomation1,2

  • Administer CroFab® as soon as possible in patients who develop any signs of envenomation (eg, local injury, coagulation abnormality, or systemic signs of envenomation) to prevent clinical deterioration. CroFab® was shown in clinical studies to be effective when given within 6 hours of snakebite
  • CroFab® is available as a lyophilized powder

Dosing to Gain Initial Control1:

  • Pediatric CroFab® dose is the same as adult dose
  • The starting dose of CroFab® may vary from a minimum of 4 vials to a maximum of 12 vials based on clinical judgment and severity of envenomation
  • If necessary, administer an additional 6 vials of CroFab® ~1 hour after end of first infusion

Vial imagery

Check for Signs of Initial Control

Signs of initial control include1:

  • Halting of the progression of local effects, such as edema and ecchymosis
  • A clear trend toward improvement in coagulation abnormalities, such as thrombocytopenia and spontaneous bleeding
  • Resolution of all systemic effects*, such as nausea, vomiting, dizziness, or tachycardia

Dosing to Continue Control1:

Continue CroFab® dosing to help prevent recurrent venom effects1

  • Treat adult and pediatric patients with scheduled maintenance dosing after initial control is established
  • Administer an additional 2-vial dose of CroFab® every 6 hours for up to 18 hours (a total of 3 doses)

Maintenance therapy is additional CroFab® given after initial control to prevent recurrence of venom effects.

2-vial dose every 6 hours


*Efficacy determined using the snakebite severity score (SSS), a validated objective tool for the clinical evaluation of North American pit viper snakebite in adults. The total score reflects patient evaluation on 6 dimensions: cardiovascular system, local wound, gastrointestinal system, hematologic symptoms, pulmonary system, and central nervous system. The higher the total score, the more severe the snakebite.1

Watch Dr. William Banner discuss his approach to dosing antivenom for children.

Administering CroFab® to Achieve Control1:

  • Establish IV access and give IV fluids
  • Initiate first dose of CroFab® in ED or ICU
  • Mix 4-6 vials of CroFab® in 250 mL normal saline (0.9% sodium chloride)
  • Infuse over 60 minutes, proceeding slowly over the first 10 minutes at a 25- to 50-mL/hour rate with careful observation for any allergic reaction
  • If no allergic reaction occurs, increase infusion rate to the full 250 mL/hour until completion
  • Close patient monitoring is necessary
    • Post-marketing data reports low rates of acute (8%) and delayed (13%) hypersensitivity3
  • For patients in shock or with serious active bleeding, call physician-expert
  • For suspected adverse reaction: Hold infusion, treat accordingly, and call physician-expert
    • Re-examine patient for treatment response within 1 hour of completion of CroFab® infusion

Initial dose may vary from a minimum of 4 to a maximum of 12 vials based on clinical judgment and severity of envenomation.

Watch a video on the reconstitution process for CroFab®.


1. CroFab® [prescribing Information]. BTG International Inc; January 2018. 2. Lavonas EJ, Ruha AM, Banner W, et al. Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop. BMC Emerg Med. 2011;11:2. 3. Schaeffer TH, Khatri V, Reifler LM, Lavonas EJ. Incidence of immediate hypersensitivity reaction and serum sickness following administration of crotalidae polyvalent immune Fab antivenom: a meta-analysis. Acad Emerg Med. 2012;19(2):121-131.