Antivenin Black Widow Spider

Generic name: latrodectus mactan
Dosage form: kit
Drug class:Antitoxins and antivenins

Medically reviewed by Drugs.com. Last updated on May 1, 2022.

Antivenin Black Widow Spider 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 single-dose 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.

Antivenin Black Widow Spider - Clinical Pharmacology

The pharmacological mode of action is unknown and metabolic and pharmacokinetic data in humans are unavailable.

Indications and Usage for Antivenin Black Widow Spider

Antivenin (Latrodectus mactans) is used to treat patients with symptoms due to bites by the black widow spider (Latrodectus mactans). Early use of the Antivenin is emphasized for prompt relief.

Local muscular cramps begin from 15 minutes to several hours after the bite which usually produces a sharp pain similar to that caused by puncture with a needle. The exact sequence of symptoms depends somewhat on the location of the bite. The venom acts on the myoneural junctions or on the nerve endings, causing an ascending motor paralysis or destruction of the peripheral nerve endings. The groups of muscles most frequently affected at first are those of the thigh, shoulder, and back. After a varying length of time, the pain becomes more severe, spreading to the abdomen, and weakness and tremor usually develop. The abdominal muscles assume a boardlike rigidity, but tenderness is slight. Respiration is thoracic. The pati...