ANTIVENIN (LATRODECTUS MACTANS) (Black Widow Spider Antivenin) Equine Origin DESCRIPTION

Antivenin (Latrodectus mactans) is a sterile, non-pyrogenic preparation derived by drying a frozen solution of specific venom-neutralizing globulins obtained from the blood serum of healthy horses immunized against venom of black widow spiders (Latrodectus mactans). It is standardized by biological assay on mice, in terms of one dose of Antivenin neutralizing the venom in not less than 6000 mouse LD50 of Latrodectus mactans. Thimerosal (mercury derivative) 1:10,000 is added as a preservative. When constituted as specified, it is opalescent, ranging in color from light (straw) to very dark (iced tea), and contains not more than 20.0 percent of solids. Each vial contains not less than 6000 Antivenin units. One unit of Antivenin will neutralize one average mouse lethal dose of black widow spider venom when the Antivenin and the venom are injected simultaneously in mice under suitable conditions. CLINICAL PHARMACOLOGY The pharmacological mode of action is unknown and metabolic and pharmacokinetic data in humans are unavailable. INDICATIONS AND USAGE Antivenin (Latrodectus mactans) is used to treat patients with symptoms due to bites by the blac