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Crofab Dosage

Dosage form: injection, powder, lyophilized, for solution
Drug class: Antitoxins and antivenins

Medically reviewed by Last updated on Nov 15, 2021.

For intravenous use only


  • Administer CROFAB as soon as possible in patients who develop any signs of envenomation (e.g., 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.

  • Antivenin dosage requirements are contingent upon an individual patient’s response. Based on clinical experience with CROFAB, the recommended initial dose is 4 to 6 vials; however, the starting dose may vary from a minimum of 4 vials to a maximum of 12 vials based on clinical judgment and severity of envenomation [3].

  • Observe the patient for up to 1 hour following completion of the first dose to determine if initial control of envenomation has been achieved. Initial control is achieved when local signs of envenomation are arrested (leading edge of local injury is not progressing), systemic symptoms are resolved and coagulation parameters have normalized or are trending toward normal. If initial control is not achieved by the first dose, an additional dose of 4 to 6 vials should be administered repeatedly until initial control of the envenomation syndrome has been achieved.

  • Once initial control has been achieved, additional 2-vial doses of CROFAB every 6 hours for up to 18 hours (3 doses) are recommended. Optimal dosing following the 18-hour scheduled dose of CROFAB has not been determined. Additional 2-vial doses may be administered as deemed necessary by the treating physician, based on the patient’s clinical course.

  • Infusion reactions, such as fever, low back pain, wheezing and nausea, may be related to the rate of infusion and can be controlled by decreasing the rate of administration of the solution [12]. Poison control centers are a helpful resource for individual treatment advice.

Preparation and Administration

  • Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

  • Reconstitute each vial of CROFAB with 18 mL of 0.9% Sodium Chloride (diluent not included) and mix by continuous manual inversion at the rate of one to two inversions per second until no solid material is visible in the vial (the fully reconstituted product will still be opalescent). Do not shake as this can cause foaming. Further dilute the contents of all of the reconstituted vials to a total volume of 250 mL with 0.9% Sodium Chloride and mix by gently swirling.

  • Use the reconstituted and diluted product within 4 hours.

  • Infuse the dose intravenously over 60 minutes. However, the infusion should proceed slowly over the first 10 minutes at a 25- 50 mL/hour rate with careful observation for any allergic reaction. If no such reaction occurs, the infusion rate may be increased to the full 250 mL/hour rate until completion. Close patient monitoring is necessary.

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