Safety Profile

A safety profile you can count on1

Since 2001, safety data have been collected on CroFab® Crotalidae Polyvalent Immune Fab (Ovine) in the treatment of North American pit viper envenomation.

In a recent meta-analysis, the incidence of immediate hypersensitivity reactions and serum sickness was 8% (95% CI = 5% to 11%) and 13% (95% CI = 7% to 21%), respectively.*

  • Sensitivity analysis excluding 2 premarketing trials, one with potential Fc contamination, reduced the estimated serum sickness to 8% (95% CI = 4% to 16%)
  • To learn more, see Important Safety Information

*Meta-analysis of CroFab® studies from January 1997 (prior to FDA approval in 2000) to September 2010.


Incidence of clinical adverse events in studies of CroFab®

Adverse events Number of events (N=42)*
Body as a whole 8  Back pain (2), chest pain (1), cellulitis (1), wound infection (1), chills (1), allergic reactions (1), serum sickness (1)
Skin and appendages 16  Urticaria (7), rash (5), pruritus (3), subcutaneous nodule (1)
Cardiovascular system 1  Hypotension
Respiratory system 3  Asthma (1), cough (1), increased sputum (1)
Digestive system 4  Nausea (3), anorexia (1)
Hematologic system 4  Coagulation disorder (3), ecchymosis (1)
Musculoskeletal 1  Myalgia
Nervous system 3  Circumoral paresthesia (1), general paresthesia (1), nervousness (1)
Early serum reactions 7  Urticaria (5), cough (1), allergic reactions (1)
Late serum reactions 5  Rash (2); pruritus (1), urticaria (1), serum sickness § (1)

*Of the 42 patients receiving CroFab® in the clinical studies, 25 experienced an adverse event. A total of 40 adverse events were experienced by these 25 patients.

Six of 42 patients experienced an adverse event associated with an early serum reaction, and 4 experienced an adverse event associated with a late serum reaction. Two additional patients were considered to have a late serum reaction by the investigator, although no associated adverse event was reported.

Allergic reactions consisted of urticaria, dyspnea, and wheezing in 1 patient.

§Serum sickness consisted of severe rash and pruritus in 1 patient.

A retrospective study of postmarketing use of CroFab® reported 36 immediate adverse drug reactions in 6.1% (15/247) of patients, including:

  • 11 immediate serious adverse events related to CroFab® in 4 patients: 2 episodes each of hypotension and tongue swelling, and 1 episode each of chest discomfort, angioedema, bronchospasm, wheezing, tracheal edema, dyspnea, and lip swelling.
  • 22 immediate nonserious adverse events related to CroFab® in 12 patients: 4 episodes each of rash and pruritus, 3 of urticaria, and 1 each of tachycardia, tachypnea, erythema, swelling, hyperhidrosis, dizziness, headache, musculoskeletal chest pain, chills, feeling cold, and nervousness
  • 2 patients reported delayed hypersensitivity reactions

In a nonconcurrent, observational, cohort study of 93 patients with North American rattlesnake bites treated with CroFab®: 5 patients (5%) had acute hypersensitivity reactions, 4 (4%) developed a mild, easily treated reaction and could finish the full course of antivenom, and only 1 patient developed a reaction that prevented further antivenom administration.10