Treatment of snakebite poisoning.

The epidemiology, mechanics, prevention, pharmacology, clinical manifestations, and treatment of snakebites are reviewed. Poisonous snakes bite approximately 8000 persons annually in the United States, causing approximately 12-15 deaths per year. Pit vipers (rattlesnakes, copperheads, cottonmouths, and massasaugas) are responsible for 99% of all snakebite poisonings; coral snakes and other foreign exotic species are responsible for the additional 1%. Envenomation is characterized by pain, edema, and ecchymoses at or near the site of venom injection, followed by cardiac, hematologic, neurologic, renal, and pulmonary toxicity. The major clinical finding in most snakebite poisonings is local tissue necrosis. Immediate treatment for snakebite includes limiting movement and placing a constriction band proximal to the site of venom injection. If medical care is more than 30 minutes away, the wound may be incised and suctioned. Antivenin therapy is the mainstay of medical treatment of snakebite, along with administration of plasma expanders, pain medication, diazepam, tetanus toxoid, antiseptics, and antibiotics. Patients who have pain, swelling, ecchymoses, systemic symptoms, or abnormal laboratory findings within 30 minutes to one hour of a bite are probable candidates to receive antivenin therapy. Before receiving antivenin therapy, the patient must be tested for hypersensitivity to the antivenin. Antivenin therapy is most effective when given within four hours of the snakebite. Pharmacists--especially those serving rural areas--should be familiar with current snakebite treatments, both local and systemic, and should be prepared to provide important information and dispel any myths about snakebite poisoning.