Dosing and Administration
Appropriate Dosing of CroFab® Achieves Initial and Sustained Control of Envenomation1
CroFab® should be administered as soon as possible in patients with any sign of envenomation (e.g., local, systemic, or hematologic effects) to prevent clinical deterioration.
- Administer an initial dose of 4-6 vials* and monitor for signs of progression
- Administer an additional 4-6 vials if initial control is not achieved ~1 hr after initial dose
- Once initial control is achieved, administer an additional 2 vials every 6 hr for up to 18 hr (total of 3 doses)
- Scheduled maintenance dosing reduced the incidence of coagulation abnormalities due to residual venom
In pre- and postmarketing studies, 67-88% of patients achieved initial control with an initial dose of 4-6 vials when given according to recommended dosing.2,3
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
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
- Postmarketing data showed low rates of hypersensitivity reactions (1.4% and 2.7%) in two studies including 1340 and 373 patients, respectively4,5
- 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
Watch a video on the reconstitution process for CroFab®.
1. CroFab® [prescribing Information]. BTG International Inc; January 2018. 2. Dart RC, Seifert SA, Boyer LV, et al. A randomized multicenter trial of crotalinae polyvalent immune Fab (ovine) antivenom for the treatment for crotaline snakebite in the United States. Arch Intern Med. 2001;161(16):2030-2036. 3. Lavonas EJ, Gerardo CJ, O'Malley G, et al. Initial experience with Crotalidae polyvalent immune Fab (ovine) antivenom in the treatment of copperhead snakebite. Ann Emerg Med. 2004;43(2):200-206. 4. Khobrani M, Huckleberry Y, Boesen KJ, Aljabri A, Alharthi M, Patanwala AE. Incidence of allergic reactions to Crotalidae polyvalent immune Fab. Clin Toxicol. 2019;57(3):164-167. 5. Kleinschmidt K, Ruha AM, Campleman S, Brent J, Wax P; ToxIC North American Snakebite Registry Group. Acute adverse events associated with the administration of Crotalidae polyvalent immune Fab antivenom within the North American Snakebite Registry. Clin Toxicol. 2018;56(11):1115-1120.