At initial examination, certain immediate, life-saving
measures may be needed. Beyond this, treatment for toxicosis includes three basic
principles: 1) prevention of further absorption, 2) supportive/symptomatic
treatment, and 3) specific antidotes.
Prevention of Further Absorption
Topically applied toxicants usually can be removed by
thorough washing with soap and water; clipping of the hair or wool may be
necessary. Emesis is of value in dogs, cats, and pigs if done within a few hours
of ingestion. Emesis is contraindicated when the swallowing reflex is absent;
the animal is convulsing; corrosive agents, volatile hydrocarbons, or petroleum
distillates are involved; or risk of aspiration pneumonia is imminent. Oral
emetics include syrup of ipecac (10–20 mL, PO in dogs) and hydrogen peroxide (2
mL/kg, PO). Apomorphine can be used in dogs parenterally at a dosage of 0.05–0.1
Gastric lavage, using an endotracheal tube and the largest
bore stomach tube possible, is done on the unconscious or anesthetized animal.
The head is lowered to a 30° angle, and 10 mL of lavage fluid (water or saline)
per kg of body weight is gently flushed into the stomach and then removed. This
process is repeated until returned fluid is clear. Cathartics and laxatives may
be indicated in some instances for more rapid elimination of the toxicant from
the GI tract. A gastrotomy or rumenotomy may be necessary when lavage techniques
are insufficient (or too slow in ruminants).
When the toxicant cannot be physically removed, certain
agents administered orally can adsorb it and prevent its absorption from the
alimentary tract. Activated charcoal (1–2 g/kg) effectively adsorbs a wide
variety of compounds and usually is the adsorbent and detoxicant of choice when
toxicosis is suspected. The maximum amount of a drug adsorbed by activated
charcoal is ~100–1,000 mg/g of charcoal. Sorbitol is sometimes added to
activated charcoal to increase its palatability (in people) and to increase the
GI transit time and flush out charcoal-bound toxins more rapidly. Activated
charcoal should not be used in animals with known hypersensitivity or allergy to
the drug. With administration of high doses, vomiting, constipation, or diarrhea
may occur, and feces will appear black.
Supportive therapy is often necessary until the toxicant
can be metabolized and eliminated. The type of support required depends on the
animal's clinical condition. Supportive efforts may include control of
convulsive seizures, maintenance of respiration, treatment for shock, correction
of electrolyte imbalance and fluid loss, and control of cardiac dysfunction, as
well as alleviation of pain.
Specific antidotes for various toxicants work by various
mechanisms. Some complex with the toxicant (eg, the oximes bind with
organophosphorous insecticides, and EDTA chelates lead). Others block or compete
for receptor sites (eg, vitamin K competes with the receptor for coumarin
anticoagulants). A few affect metabolism of the toxicant (eg, nitrite and
thiosulfate ions release and bind cyanide).
Last full review/revision October 2013 by Steve M. Ensley, BS, DVM, MS, PhD