CroFab is indicated for the management of patients with minimal or moderate NorthAmerican crotalid envenomation (see Table 3 in Clinical Studies section for definitions). Early use of CroFab (within 6 hours of snakebite) is advised to prevent clinical deterioration and the occurrence of systemic coagulation abnormalities.

Each vial of CroFab should be reconstituted with 10 mL of Sterile Water for Injection USP (diluent not included) and mixed by continuous gentle swirling. The contents of the reconstituted vials should be further diluted in 250 mL of 0.9% Sodium Chloride USP and mixed by gently swirling. The reconstituted and diluted product should be used within 4 hours.

Administration of antivenin should be initiated as soon as possible after crotalid snakebite in patients who develop signs of progressive envenomation (e.g., worsening local injury, coagulation abnormality, or systemic signs of envenomation). CroFab was shown in the clinical studies to be effective when given within 6 hours of snakebite.

Antivenin dosage requirements are contingent upon an individual patient†s response; however, based on clinical experience with CroFab, the recommended initial dose is 4 to 6 vials. The patient should be observed for up to 1 hour following the completion of this first dose to determine if initial control of the envenomation has been achieved (as defined by complete arrest of local mani-festations, and return of coagulation tests and systemic signs to normal).If initial control is not achieved by the first dose, an additional dose of 4 to 6 vials should be repeated until initial control of the envenomation syndrome has been achieved. After initial control has been established, additional 2-vial doses of CroFab every 6 hours for up to 18 hours (3 doses) is 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.

The initial dose of CroFab diluted in 250 mL of saline should be infused 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.

Additional Patient Care (Supportive and Adjunctive Therapy)

Supportive measures are often utilized to treat certain manifestations of crotalid snake envenomation, such as pain, swelling, hypotension, and wound infection. Poison control centers are a helpful resource for individual treatment advice.

CroFab is supplied as a sterile, nonpyrogenic, purified, lyophilized preparation. Each vial contains up to 1 g of total protein, a maximum of 0.11 mg of mercury, and not less than the indicated number of mouse LD₅₀ neutralizing units:

Each box contains 2 vials of CroFab (diluent not included).

Storage Conditions

The product should be stored at 2° to 8°C (36° to 46°F). Do not freeze. The product must be used within 4 hours after reconstitution.

REFERENCES

1. Consroe P,Egen NB,Russell FE,Gerrish K,Smith DC,Sidki A,et al.Comparison of a new ovine antigen binding fragment (Fab) antivenin for United States Crotalidae with the commercial antivenin for protection against venom-induced lethality in mice. J Trop Med Hyg 1995; 53(5):507-510.

2. Dart RC, Hurlbut KM, Garcia R, Boren J.Validation of a severity score for the assessment of Crotalid snakebite. Ann Emerg Med 1996; 27(3):321-326.

3. La Grange RG and Russell FE. Blood platelet studies in man and rabbits following Crotalus envenomation. Proc West Pharmacol Soc 1970;13:99-105.

4. Lyons WJ. Profound thrombocytopenia associated with Crotalus ruber ruber envenomation: a clinical case. Toxicon 1971; 9:237-240.

5. Tallon RW,Koch KL,Barnes SG,Ballard JO.Letter to Editor.N Engl J Med 1981;305:1347.

6. Quarre JP,Lecomte J,Lauwers D,Gilbert P,Thiriaux J.Allergy to latex and papain.J Allergy Clin Immunol 1995; 95(4):922.

7. Baur X,Chen Z,Rozynek P,Düser D,Raulf-Heimsoth M.Cross-reacting IgE antibodies recognizing latex allergens,including Hev b 1,as well as papain.Allergy 1995; 50(7):604-609.

8. Furlow TG, Brennan LV. Purpura following timber rattlesnake (Crotalus horridus horridus) envenomation. Cutis 1985; 35:234-236.

9. Budzynski AZ,Pandya BV,Rubin RN,Brizuela BS,Soszka T,Stewart GJ.Fibrinogenolytic afibrinogenemia after envenomation by western diamondback rattlesnake (Crotalus atrox).Blood 1984; 63(1):1-14.

10. Kojis FG.Serum sickness and anaphylaxis.Am J Dis Child 1997;93-350.

11. Kirkpatrick CH,The Digibind Study Advisory Panel.Allergic histories and reactions of patients treated with digoxin immune Fab (ovine) antibody.Am J Emerg Med 1991; 9(2 Suppl 1):7-10.

Manufactured by: Protherics Inc. Nashville,TN 37212 Distributed by: Savage aboratories,a division of Altana Inc. Melville,NY 11747 U.S.License No.1575 Revised April 2002 462531

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