Efficacy of antivenom in the treatment of severe local envenomation by the hump-nosed viper (Hypnale hypnale).

In Sri Lanka, the usual treatment for severe local envenomation by the hump-nosed viper (Hypnale hypnale) is with polyspecific snake antivenom. We carried out a prospective, randomized, placebo-controlled, single-blind clinical trial to determine the efficacy and safety of polyspecific snake antivenom in the treatment of severe local envenomation by this snake. Sixty-three patients with signs and symptoms of local envenomation by the hump-nosed viper Lanka were randomized to receive either polyspecific snake antivenom or normal saline.