Acetaminophen is a common, non-aspirin pain
reliever found in many home remedies, particularly all Tylenol
products. Acetaminophen is very toxic to cats and can be toxic to dogs
as well. Normal adult acetaminophen tablets contain 325 mg. The toxic
dose for cats is 10 mg/kg (so the average 8 pound or 4 kg cat would be
toxic tat 40 mg or 1/10th of a tablet!. In dogs, the toxic
dose is 150 mg/kg of body weight, so a single tablet is unlikely to be
dangerous to any dog above 10 pounds. However, sometimes dogs will eat
many tablets at one time, which can be toxic depending on the weight of
the pet.
Principle of Toxicity: Acetaminophen interferes
with the metabolism of a chemical called glutathione. Glutathione is
important in protecting the liver and red blood cells from damage caused
by oxidative stress. As a result, the hemoglobin in the red cells may
become non functional (met-hemoglobin) and unable to carry oxygen
properly. This form of hemoglobin causes the pets mucus membranes to
turn a muddy brown color. In addition, damaged red blood cells are
destroyed by the body leading to severe anemia. Moreover, acetaminophen
can cause liver damage and liver failure.
Clinical Symptoms: Swelling of the face and
feet, excessive salivation, muddy brown colored mucus membranes, bluish
color to tongue, icterus (yellow tinge to mucus membranes and whites of
eyes, hyperventilation and vomiting.
Diagnosis: The diagnosis of Acetaminophen
toxicity is based on known ingestion of the drug, or a combination of
the clinical symptoms and results of blood tests, which may include:
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Anemia
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Heinz body formation in the red blood cells
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Increased liver enzymes
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Characteristic brown color of blood.
Treatment: Treatment includes purging the
drug from the system (if known ingestion has occurred) by inducing
vomiting and/or gastric lavage. Administering activated charcoal in the
stomach to help absorb the drug before it is absorbed.
A number of drugs can help counteract the effects
of this drug including:
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Acetylcysteine
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S-Adenosylmethionine
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Cimetidine
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Vitamin C
General supportive care, including intravenous
fluids, oxygen support, blood transfusions etc.
Prognosis: The prognosis in this
intoxication is linked to the size and species of animal (smaller
animals and cats have worse prognosis), the amount of drug ingested and
the amount of time passing before diagnosis. This drug can be fatal,
especially to cats. So, early detection and aggressive treatment is
critical. With early detection and treatment, many of these pets can be
saved.
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