Risk of immediate effects from F(ab)2 bivalent antivenin in Taiwan.

OBJECTIVE: To evaluate the incidence of immediate adverse effects from equine fragment antigen binding F(ab)2 bivalent antivenin produced by the National Institute of Preventive Medicine (NIPM) in Taiwan. METHODS: A retrospective chart review of patients presenting to a 600-bed general hospital over a 3-year period with snakebite who were treated with NIPM antivenin. RESULTS: A total of 130 snakebite victims presented to the emergency department over the study period, and 159 vials of antivenin were given. One hundred two patients (78.5%; 95% CI: 70, 85) received only hemorrhagic bivalent antivenin, 2 (1.5%; 95% CI: 0, 5) received only neurotoxic bivalent antivenin, and the remaining 26 (20.0%; 95% CI: 13, 28) received both kinds of bivalent antivenin. Three received a second vial of hemorrhagic antivenin because of progression of symptoms. Forty-two patients (32.3%; 95% CI: 24, 41) had positive skin tests, but following pretreatment with diphenhydramine and hydrocortisone, only 1 patient developed a skin rash thought to be related to antivenin. No patient developed an anaphylactic reaction. CONCLUSIONS: The use of NIPM F(ab)2 antivenin in snakebite victims in Taiwan has a very low risk of acute adverse reactions.