Efficacy of delayed administration of crotalid antivenom and crystalloid fluids.

Clinical and research reports suggest that the efficacy of antivenom declines when its administration is delayed after envenomation. A controlled sequential trial was performed comparing the efficacy of three treatments to untreated controls when applied 1 hr after subcutaneous injection of rats with Crotalus atrox venom. Survival was decreased in all groups when treatment was delayed for 1 hr. Survival was highest in animals treated with both antivenom and saline, followed by antivenom alone, saline alone and then untreated animals.