Definition and Use
Antivenin is a serum product, also called antivenom, cultivated from animal blood and given therapeutically to neutralize the effects of poisonous venoms such as from bites and stings. It is specific to a particular venom and works by activating antibodies that enable the person’s immune system to fend off the effects of the venom.
When possible, safely capture the snake or spider that renders the bite for positive identification and the correct antivenin.
A person generally must receive serum within about four to eight hours of the bite or sting for the antivenin to be effective. Serum is commonly available in the United States for the bites of indigenous snakes and spiders and the stings of scorpions.
There are facilities in many parts of the United States that stock antivenin for exotic snakes and spiders that may enter the country inadvertently (such as among produce), as pets, or for scientific research or display (as in zoos). Local and regional poison control centers know what antivenin products are available and how to obtain them.
Most serums are cultivated from the blood of horses so it is important to know a person’s allergy history. Allergic reaction to antivenin is not uncommon. Even in people who have a known allergy to horses, however, the antivenin may be lifesaving. Generally in such a situation the administration of antihistamine medications and epinephrine will mitigate the allergic response to allow the antivenin to be effective.
Serum sickness, an immune reaction to the antigens and blood proteins present in products derived from nonhuman blood, may also occur. Serum sickness generally begins one to two weeks after administration of the antivenin and runs its course over about three weeks. The risk for allergic reaction and serum sickness increases with higher doses of antivenin.
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