Comment on “Crotalidae Polyvalent Immune Fab and Cost-Effective Management of Hospital Admissions for Snakebites”

The authors have overlooked confounders such as the culprit snake species, the anatomic locations of bites, and the presenting severity of envenomation that better explain the apparent outcomes. [...]the adverse events attributable to Fab AV mainly are mild skin reactions or nausea/vomiting. 4 The similarity in clinical outcomes with or without Fab AV reflects the imbalance in culprit snake species. When the FDA approved Fab AV in 2000, the package insert recommended “close patient monitoring and readiness with intravenous therapy using epinephrine and diphenhydramine hydrochloride” while acknowledging that no patient in the pre-approval trials had any anaphylaxis. 5 This warning was a carry-over from the Wyeth Antivenin Crotalidae Polyvalent® (ACP, Wyeth Pharmaceuticals, Collegeville, PA) which preceded Fab AV. Long ago discontinued, Wyeth ACP contained whole immunoglobulins derived from horse serum and was considerably more antigenic than Fab AV. We believe it is likely that hospital policy two decades ago required ICU admission for any patient receiving Fab AV. Obsolete, twenty-year-old hospital policies compelling ICU care likely predated the authors’ time at Atrium Navicent Health and could now be inaccessible.