Incidence of immediate hypersensitivity reaction and serum sickness following administration of Crotalidae polyvalent immune Fab antivenom: a meta-analysis.
OBJECTIVE
Crotalidae polyvalent immune Fab (ovine) (FabAV) is commonly used in the treatment of symptomatic North American crotaline snake envenomation. When approved by the U.S. Food and Drug Administration in 2000, the incidences of immediate hypersensitivity reactions and serum sickness were reported as 0.14 and 0.18, respectively. The objective of this meta-analysis was to evaluate the incidence of immediate hypersensitivity reactions and serum sickness reported in studies of patients treated with FabAV therapy after North American crotaline envenomation.


METHODS
The authors searched PubMed, Ovid MEDLINE, and EMBASE from January 1, 1997, to September 20, 2010, for English-language medical literature and cross-referenced bibliographies of reviewed articles. The published abstracts of the major toxicology conferences were also searched. All prospective and retrospective cohort studies with patients receiving FabAV therapy for North American crotaline envenomations were eligible for data abstraction. Two content experts reviewed full-text articles and extracted relevant study design and outcome data. Proportions of immediate hypersensitivity and serum sickness for each study were analyzed in a random-effects model to produce an overall estimate of immediate hypersensitivity and serum sickness incidence associated with FabAV administration.


RESULTS
The literature search revealed 11 unique studies of patients who received FabAV that contained information on immediate hypersensitivity reactions and serum sickness. The meta-analysis produced a combined estimate of the incidence of immediate hypersensitivity of 0.08 (95% confidence interval [CI] = 0.05 to 0.11) and a combined estimate of the incidence of serum sickness of 0.13 (95% CI = 0.07 to 0.21).


CONCLUSIONS
In this systematic literature review and meta-analysis, the combined estimates of the incidence of immediate hypersensitivity reactions and serum sickness from FabAV in the treatment of symptomatic North American crotaline envenomations appear to be lower than previously reported, at 0.08 and 0.13, respectively.
Rocky Mountain Poison & Drug Center, Denver Health and Hospital Authority, Denver, CO, USA. tammi.schaeffer@rmpdc.org.
Tammi H
TH
Schaeffer
Vaishali
V
Khatri
Liza M
LM
Reifler
Eric J
EJ
Lavonas
D000818:Animals; D000997:Antivenins / Q000009:adverse effects*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000139:chemically induced* / Q000453:epidemiology; D007140:Immunoglobulin Fab Fragments; D007128:Immunoglobulin Fragments / Q000009:adverse effects*; D015994:Incidence; D012713:Serum Sickness / Q000139:chemically induced* / Q000453:epidemiology; D012909:Snake Bites / Q000188:drug therapy* / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
D000997:Antivenins; C431183:Crotalidae Polyvalent immune Fab; D007140:Immunoglobulin Fab Fragments; D007128:Immunoglobulin Fragments