antivenin 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.
Antivenin is specific to a particular venom and
works by activating antibodies that enable the per-
son’s IMMUNE SYSTEMto fend off the effects of the
venom.
When possible, safely capture the snake
or spider that renders the bite for posi-
tive identification and the correct
antivenin.A person generally must receive antivenin
within about four to eight hours of the bite or
sting for the antivenin to be effective. Antivenin 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 antivenins 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
ALLERGYto horses, however, the antivenin may be
lifesaving. Generally in such a situation the
administration of ANTIHISTAMINE MEDICATIONS and
EPINEPHRINEwill mitigate the allergic response to
allow the antivenin to be effective. Serum sick-
ness, 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 adminis-
tration 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.
See also ANTIBODY; ANTIGEN; HYPERSENSITIVITY
REACTION.152 Drugs