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Toxicology
WEEK 6
Toxicants and Toxins
 Proper and prompt tx of poisonings, including
stabilization and decontamination, is essential
 Toxicants- of biologic origin, manufactured
chemicals, or naturally occurring chemicals
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Any substance that when introduced into or applied to the
body can interfere with the life processes of cells of the
organism.
 Toxin- noxious or poisonous substance that is
formed or elaborated during the metabolism and
growth of certain microorganisms and some higher
plant and animal species
You as a technician
 Should be able to recognize what constitutes a
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toxicological emergency and what does not
Be able to give basic first aid advice, and provide
clear directions to the hospital
Can prepare for arrival with necessary equipment
and medication
Investigate the toxicant
Direct owner to contact the ASPCA poison control
center (888-426-4435)
Questions to ask when the owner calls
 What is the current clinical status of the animal
 What was the animal exposed to and through what
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route
Has the owner taken any steps to treat the animal
Age and weight of animal
How much was ingested
When was the exposure
Male or female; if female, lactating or pregnant
Any Hx of health problems
On any current medication
Had any recent Sx
Assesment
 1st thing is assess animals condition
 Performed quickly and includes: examination of RR,
CRT, MM color, HR, and temp
 Unconscious, in shock, seizuring, or cardiovasular or
resp distress must be conducted simultaneously with
stabilization measures
 Look for any evidence of hemorrhaging
Stabilization
 General rule: treat the patient not the poison
 Establish and maintain patient airway
 Cardiovascular system should be monitored
 Apply O2 or artificial respirations if needed
 Place an indwelling IV catheter for administration of
any necessary injections
Decontamination
 Must know patients:
 Age
 Weight
 Previous medical Hx
 Treat appropriately
External exposures
 Ocular irrigation
 Eyes flushed repeatedly with water or saline for a minimum of
20-30 minutes and treat with lubricant ointment
 Corrosive agents considered an emergency
 Examination for corneal damage and monitor for excessive
redness, lacrimation or pain
 Never use topical steroids with ocular scratches/ulcerations
 Bathing
 Dermal exposures
 Use mild liquid dishwashing detergent
 Rinse well
 Towel dry
Oral ingestion
 Types of tx:
 Dilution
 Emesis
 Activated charcoal
 Cathartics
 Enemas
 Gastric lavage
 Supportive care
Emesis
 Vomiting
 Patient’s species, time past ingestion, previous and
current Hx, and type of poison can effect decision
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Best results within 2-3 hours postexposure
 Contraindicated in: rodents, rabbits, birds, horses,
and ruminants
 Contraindicated with previous Hx of heart
abnormalities, epilepsy, or abdominal Sx, corrosive
material
 Feeding small meal prior increases adequate emesis
Agents
 3% H2O2:
 1 teaspoon per 5lbs
 Repeat if no vomiting within 15-20 minutes
 H2O2 must be fresh
 Do not exceed 3 tbsp
 Apomorphine:
 Preferred emetic
 Available in injectable or capsule
 Capsule admin in the conjuctiva
Activated charcoal
 Absorbs a chemical or toxicant and facilitates its
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excretion via the feces
Dose 1-3g/kg of body weight, repeated every 4-8
hours at ½ the original dose
Administered orally or through stomach tube
Not used in animals that ingested caustic materials
Very messy to administer
Cathartics
 Used to enhance elimination of activated charcoal
and absorbed toxicant
 Contraindicated with patients with:
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Diarrhea
Dehydration
 Enemas are a type of cathartic
 Helpful in elimination of toxicants from the lower GI tract
 Use warm plain water or warm soapy water
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Premixed solutions have potential for electrolyte and/or acid-base
imbalance
Gastric Lavage
 Gently pumping out of the stomach contents
 Usually performed under general anesthesia
 Pumped repeatedly with body temp water until it
comes out clear
 Enterogastric lavage: occasionally done after gastric
lavage
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Leave stomach tube in place
Perform an enema
Distal end of enema tube is attached to a water faucet and
body temp water is ran trough until it comes out of the
stomach tube, repeat until clear
Considered the “through and through” method
Supportive Care
 Tech plays critical role in routinely evaluating vital
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signs and parameters poss. Affected by toxicants
Check hydration
Blood samples
Watch for overhydration
Diuresis may be beneficial for exposures to toxicants
that can cause kidney damage
Nutrition can be key component in recovery
Tech should educate owners on dangers of toxicants
Topical Insecticides
 Some common topical insecticides can produce
topical allergic reactions.
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Imidacloprid (_____)
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Fipronil (_____)
Selamectin (_____)
Methoprene (Hartz)
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In combination with permethrin for ticks- K9 Advantix
In combination with Fipronil is Frontline Plus
Pyrethroids
Most commonly see toxicity due to “piggyback” use causing
overdose. May see neurologic signs. Tx by bathing
Topical Insecticides
 Permethrin toxicity
 A synthetic pyrethroid compound with insecticidal properties
 Used in the control of fleas and ticks
 Clinical signs of toxicity
 Generalized tremors, muscle fasciculations, and seizures
 Most common in cats due to the misapplication of products
intended for dogs
Topical Insecticides
 Permethrin toxicity diagnosis
 History of exposure and subsequent development of clinical
signs
 Permethrin toxicity treatment
 Decontamination of the skin via bathing
 Bathing symptomatic cats may be difficult, but is important in
preventing further uptake of the toxin
 Muscle relaxants, anti-convulsants and sedative drugs can be
useful in the symptomatic treatment of seizures, tremors, and
muscle fasciculation
Topical Insecticides
 Permethrin toxicity fluid therapy
 Indicated to correct dehydration that develops from
hypersalivation and protracted muscle activity
 Fluid therapy and bathing are helpful in managing potential
hyperthermia
 Overall prognosis for cats that receive prompt treatment is
good
Household cleaning agents
 Acids
 Alkali
 Bleaches
 Detergents
Misc Household items
 Ant baits
 Silica gel packets
 Toilet water with tank cleaning drop-in tablets
 Glow necklaces
 Liquid potpourri
 Batteries
 Cigarettes
 Pennies
 Mothballs
 Moldy food
 Ice and snow melts
Dangerous Foods
 Moldy food
 Chocolate- dark more toxic than milk, unsweetened baking
more toxic than dark
 Onions- causes damage to RBCs causing hemolysis
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Uncooked more toxic than cooked. Onion powder can also be toxic
 Macadamia Nuts- dogs
 Rising bread dough
 Grapes and raisins- kidney failure in dogs
 Tobacco
 Xylitol- most commonly found in gum and pop
 Causes hypoglycemia
Dangerous Foods
 Chocolate
 Toxic ingredient is Theobromine however the
caffeine will also effect them
 Toxic dosages:
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White chocolate is not toxic
Milk chocolate 2 oz/kg dog
Semisweet 0.7 oz/kg
Bakers chocolate 0.25 oz/kg
Unsweetened cocoa 0.1 oz/kg
www.aspca.org
Dangerous Foods
 Chocolate
 Signs
 V and D, hyperactivity, muscle tremors, tachycardia,
hypertension, +/- seizures
 Treatment
 Induce vomiting, gastric lavage may be necessary
 Activated charcoal given after
 IV fluids, +/- oxygen therapy
Dangerous Foods
 Grapes/Raisins
 Effects dogs, unknown reason or cause
 Side effects
 Kidney failure
 Treatment
 Symptomatic and supportive care
Dangerous Foods
 Xylitol
 Signs
 GI symptoms, weakness, PU/PD, elevated liver enzymes with
acute renal failure, hemorrhage, DIC
 Treatment
 Induce vomiting
 Symptomatic and supportive care
Dangerous plants
 Rhododendron species
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Can lead to cardiovascular dysfunction
Signs- v and d, abdominal pain, weakness, depression, cardiac
arrythmias, hypotension, shock, dyspnea, CNS depression, seizures
 Cardiac Glycoside- containing plants
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Signs involve GI tract and cardio system. Toxic in very small amounts
 Castor beans
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Most potent plant toxic known- Ricin- Potentially lethal
 Cycad palms
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Effects hepatic and GI systems, results in liver failure and death in dogs
Dangerous Plants
 Lilies
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Acute renal failure and death in cats
 Calcium oxalate- containing plants
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Calcium oxalate crystals present in plant material causing painful
oropharyngeal edema.
Airway compromised from tissue swelling, can be life-threatening
Pesticides
 Systemic insecticides: Disulfoton or Disyston
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Disulfoton- toxic component
Hemorrhagic diarrhea, liver and pancreatic enzyme elevations
 Fly bait
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Seizures, effects CNS, ↑ salivation, lacrimation, urinary incontinence,
diarrhea, GI cramping and emesis
 Snail or slug bait
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Metaldehyde- toxic component
Causes- ↑HR, nervousness, tremors, hyperthermia, seizures and
poss. liver failure
 Gopher or mole bait
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Zinc phosphide- toxic component
Resp distress, death, signs within 15 minutes to 4 hours
Pesticides
 Rat or mouse bait
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Anticoagulants- inhibits vit K, animal will bleed out if
untreated
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Available in anticoagulants, bromethalin, and cholecalciferol
clinical signs of bleeding within 24-72 hours of ingestion
Bromethaline- causes ↓ of adenosine triphosphate = ↓ nerve
impulse conduction.
Cholecalciferol (vit D3)- ↑ absorption of calcium, can lead to
kidney failure, cardiovascular abnormalities, tissue
mineralization
Pesticides
 Diagnosis
 Patient history
 Prothrombin time (PT) and activated partial thromboplastin
time (PTT)
 Both become prolonged with rodenticide toxicity
 Countertop analyzers are available for rapid in-house
assessment of clotting times- very pricey to own.
Pesticides
 Rodenticide toxicity clinical signs
 Spontaneous bruising of the skin and sclera
 Bleeding into body cavities (hemothorax, hemoabdomen) and
intestinal blood loss
 If drawing blood, be careful of jugular venipuncture.
The medial saphenous in the cat, or the lateral
saphenous in the dog, is a convenient phlebotomy
site.
 Intramuscular injection is avoided because of the
risk of hematoma formation.
Pesticides
 Rodenticide toxicity treatment
 Vitamin K1 supplementation
 Coagulation abnormalities usually start to correct within 12
hours of oral vitamin K1 supplementation
 Vitamin K1 therapy can be given via subcutaneous injection
 Intravenous injection of vitamin K is contraindicated because
of the risk of anaphylaxis
 Allergic reactions to orally administered vitamin K1 are
uncommon
 Duration of vitamin K1 therapy depends upon the specific
compound ingested, but most cases are typically treated for 1
month
Antifreeze products
 Methanol
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Causes metabolic acidosis
Minimum toxic dose in dogs (8.0g/kg)
 Propylene glycol
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3x less toxic than ethylene glycol
Acidosis, liver damage, renal insufficiency and seizures are possible
 Ethylene glycol
 Active ingredient of most automotive antifreeze solutions
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Most dangerous form- min dose dogs (4.4-6.6ml/kg) cat (1.4ml/kg)
Causes metabolic acidosis and renal tubular necrosis
Emesis if recent ingestion (<1 hr), Fomepizole admin in dogs,
ethanol in dogs or cats
Ethylene Glycol
 Ethylene glycol ingestion clinical signs
 “Early” signs occur within 30 minutes to 12 hours postingestion
 Signs include vomiting, lethargy, excessive drinking/urination,
incoordination
 Neurological signs
Ataxia, proprioceptive deficits, seizures
 Initial neurological signs often diminish as ethylene glycol is
metabolized, leading to a false sense of recovery
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Ethylene Glycol
 Metabolites of ethylene glycol soon cause acute renal
failure in both cats and dogs
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Kidney failure generally develops within 12-24 hours in cats
Kidney failure with 48-72 hours in dogs
“Late” clinical signs of ethylene glycol poisoning include
renewed neurological signs from severe kidney failure
Oliguria/anuria, severe lethargy, vomiting, and dehydration
Seizures, coma, and death
Ethylene Glycol
 Ingestion diagnosis:
 Blood levels peak at 12 hours post-ingestion in dogs, 3-6 hours
post-ingestion in cats and then diminish rapidly
Definitive diagnosis requires either witnessed ingestion or
demonstration of ethylene glycol in blood or urine
 Ethylene glycol assays commercially available
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Thereafter, investigate ethylene glycol levels in the urine,
where the compound is excreted
Isosthenuria and calcium oxalate monohydrate crystals in the
urine may be seen within hours of ingestion and can be
important supporting evidence in the diagnosis of toxicity
Ethylene Glycol
 Ethylene glycol ingestion treatment
 Varies with the level of available care and the timing of
diagnosis
 Witnessed ingestion should be managed with standard
detoxification procedures including induction of vomiting and
administration of activated charcoal within 1-2 hours of
ingestion
 IV fluids, peritoneal dialysis and cathartics are recommended.
(monitor for fluid overload!)
 Standard treatment is focused on preventing metabolism of
the toxin
Ethylene Glycol
 Ethylene glycol ingestion treatment (cont’d)
 Metabolism of ethylene glycol may be inhibited by
administration of fomepizole (Antizol-Vet, Orphan Medical)
 Medical-grade ethanol can also be used to competitively
inhibit the enzymes responsible for ethylene glycol metabolism
Dangerous Human Medications
 Acetaminophen- toxic metabolite is N-acetyl-
parabenzequinoneimine
 Ibuprofen
 Aspirin
 Ma Huang, pseudoephedrine, and Ephedrine:
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sympathomimetic alkaloids
 Isoniazid
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Used in tx of TB
 Calcipotriene: Vit D derivatives
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Tx of psoriasis
 5-Fluorouracil: antimetabolites
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Anticancer topical cream
Toxicities
 Acetaminophen (Tylenol)
 Extremely dangerous in cats (1 tablet can be fatal!)
 Side effects
 Seen 1-2 hours post ingestion: dyspnea, salivation, vomiting,
brown or cyanotic MM, dark or chocolate colored blood,
edema, liver signs.
 May see death in cats within 1 hour of ingestion.
Toxicities
 Acetaminophen treatment
 Induce vomiting if <1 hour post ingestion
 Activated charcoal given after
 IV fluids and oxygen recommended if tachypnea is not present.