Is Antivenom Worthwhile for Widow Spider Bites?

Latrodectism is widow spider envenomation and is the most common, severe spider envenomation worldwide. In the largest randomized, placebo-controlled trial to date, researchers in Australia assessed the efficacy of intravenous redback spider (L. hasselti) equine antivenom for resolving pain and systemic effects from moderate-to- severe bites.

The two primary endpoints used were clinically significant pain reduction from baseline and resolution of systemic features of envenomation, both at 2 hours after study treatment. Among the 224 study participants (aged > 7 years), antivenom was no better than placebo for any measure. Mild skin hypersensitivity occurred in 4 of 112 patients (3.6%) in the antivenom group and in none of the patients receiv…