Crotalidae Polyvalent Immune Fab Ovine

Crotalidae Polyvalent Immune Fab Ovine Brand Name– CroFab

What is Crotalidae Polyvalent Immune Fab Ovine

CroFab is an antivenin used in the management of North American crotalid envenomation (rattlesnakes, copperheads, and cottonmouths/water moccasins).

It is produced by immunizing healthy sheep with one of the following North American snake venoms: Crotalus atrox (western diamondback rattlesnake), Crotalus adamanteus (eastern diamondback rattlesnake), Crotalus scutulatus (Mojave rattlesnake), and Agkistrodon piscivorus (cottonmouth or water moccasin).

Venom-specific antibody fragments (Fab) of IgG are produced for each of the four venoms and are mixed to obtain the final antivenin product known as Crotalidae polyvalent immune Fab.

Since CroFab utilizes antibody fragments, which are smaller and lack the most immunogenic portions of the antibody, this formulation is less likely to induce an antibody response than products based on intact IgG.

In addition, sheep-derived polyclonal antibodies are known to produce a decreased allergic response in humans when compared to equine-derived antibodies.

Crotalidae polyvalent immune Fab (ovine) was FDA-approved in October 2000


  • crotalid snake bite

For the management of North American crotalid snake bite (rattlesnakes, copperheads, and cottonmouths/water moccasins)

Side Effects

  1. anaphylactic shock
  2. anaphylactoid reactions
  3. angioedema
  4. anorexia
  5. antibody formation
  6. anxiety
  7. back pain
  8. bronchospasm
  9. chest pain (unspecified)
  10. chills
  11. cough
  12. dizziness
  13. dyspnea
  14. edema
  15. erythema
  16. fever
  17. headache
  18. hyperhidrosis
  19. hypotension
  20. myalgia
  21. nausea
  22. pruritus
  23. rash
  24. serum sickness
  25. sinus tachycardia
  26. tachypnea
  27. tremor
  28. urticaria
  29. wheezing

Monitoring Parameters

  • CBC with differential
  • clotting time
  • INR
  • platelet count


  • breast-feeding
  • children
  • coagulopathy
  • diarrhea
  • fever
  • heart failure
  • hepatic disease
  • hyperthyroidism
  • infants
  • latex hypersensitivity
  • malnutrition
  • neoplastic disease
  • ovine protein hypersensitivity
  • papain hypersensitivity
  • pregnancy
  • thimerosal hypersensitivity
  • vitamin K deficiency


  • Measles Virus; Mumps Virus; Rubella Virus; Varicella Virus Vaccine, Live
  • Varicella-Zoster Virus Vaccine, Live

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