Test 4: 47-48 Flashcards
what are some non toxic exposure examples
what are some things that are toxic in small doses
- Campho
- Hydrofluoric acid
- Gun blue (selenious acid)
- Benzocaine
- Acetaminophen (cats)
- Toxic alcohols (methanol, ethylene glycol)
- Aspirin and related products (cats)
- Lomotil®
- Calcium channel blockers
- Oil of wintergreen
- Calcipotriene
- 5-fluorouracil
camphor is found in
Vicks Vaporub®, Vicks Vaposteam® and Camphophenique®. Rarely found in moth repellants today.
camphor toxicity presents with
rapid-acting neurotoxin (seizures occur without warning)
Range of toxicity: death in a small child may occur with ingestion of as little as 5 mL of camphorated oil (1 gram of camphor).
vicks vaporrub
treatment for camphor
supportive care
vicks vapor rub → rapid acting neurotoxin (seizures)
narrow range of toxicity
source of hydrofluoric acid
automotive wheel cleaners, glass
etching solution
hydrofluoric acid toxicity causes
burns, electrolyte disturbances,
death. Dilute solutions (< 12%) can cause delayed injury
Toxic via all routes of exposure (even intact dermal)
source: automotive wheel cleaners, glass
etching solution
treatment for hydrofluoric acid
calcium (topical, local infusions)
Sources: automotive wheel cleaners, glass etching solution
Toxicity: burns, electrolyte disturbances, death. Dilute solutions (< 12%) can cause delayed injury.
Toxic via all routes of exposure (even intact dermal)
source of gun blue
selenious acid
Sources: gun blueing solutions (pH 1)
toxicity of gun blue
Toxicity: inorganic selenium. Serious burns, systemic toxicity (shock, seizures, severe hypotension, cardiorespiratory arrest)
gun blue toxic dose and treatment
Ingestion of a few drops of gun blue can cause illness and 15 mL or more can be fatal
Toxic via dermal route: only if denuded areas
Treatment: supportive care
Sources: gun blueing solutions (pH 1)
Toxicity: inorganic selenium. Serious burns,
systemic toxicity (shock, seizures, severe
hypotension, cardiorespiratory arrest)
benzocaine sources
Sources: oral and topical anesthetics (exs:
Orajel®, Anbesol®)
Toxicity: methemoglobinemia
Causes methemoglobinemia in cats without Heinz body formation.
Onset is usually within 20 to 60 minutes
Treatment: treat methemoglobinemia as
indicated (methylene blue)
benzocaine causes — and treatment
Sources: oral and topical anesthetics (exs:
Orajel®, Anbesol®)
Toxicity: methemoglobinemia
Causes methemoglobinemia in cats without Heinz body formation.
Onset is usually within 20 to 60 minutes
Treatment: treat methemoglobinemia as
indicated (methylene blue)
goals of gastric decontamination
to decrease the blood concentration of the toxin, to decrease the amount of toxin absorbed, and to reduce the severity of the poisoning
- any technique that prevents absorption of a drug or chemical
how to make dog and cat vomit
Dogs: 3% hydrogen peroxide, apomorphine
Cats: 3% hydrogen peroxide, xylazine, (less accepted: apomorphine)
contraindications to induce vomiting
Those species that cannot readily vomit (rodents, rabbits, horses, ruminants)
Evidence or risk of CNS depression or seizures
Caustic substances (causes burns)
Batteries or sharp foreign bodies
Substances with risk of aspiration (eg, petroleum distillates: kerosene, gasoline, motor oil, naptha )
complications of emesis
- Persistent vomiting
- Aspiration
- Vagal-induced bradycardia during vomiting
- Esophageal injury (rare)
apomorphine hydrochloride will cause
vomiting in dogs
MOA: stimulates chemoreceptor trigger zone (CTZ) then depresses emetic center.
Do not use in cats: can cause excitement
how to give apomorphone hydrochloride
conjunctival (unreliable onset of action –2-10 minutes)
Subcutaneous (SC) (2-10 minutes)
Intramuscular (IM) (5 minutes)
intravenous (IV) (immediately)
cause vomiting in dogs
what % strength of hydrogen peroxide to induce vomiting
3%
how to give hydrogen peroxide to induce vomiting
3%
give PO
onset: 10 mins
can repeat x1 if no vomiting
As with other emetics, food in stomach encourages emesis
dogs and cats
how does xylazine hydrochloride work
Alpha-2 adrenergic agonist given IM or SC
MOA: stimulates CRTZ
use in cats, not dogs
AEs: risk of hypotension, especially if cat is dehydrated
gastric lavage
emptying stomach of animal under sedation
ET tube will protect airway
allows for gastric emptying when emesis is not recommended
when to not gastric lavage
Hydrocarbons (exs: petroleum distillates, pine oil) (big concern is aspiration)
Caustics
possible complications of gastric lavage
Aspiration pneumonia
Esophageal perforation
Fluid and electrolyte imbalances:
- Hyponatremia, water intoxication (when water is used
- Hypernatremia (with large volumes of normal saline)
activated charcoal is not effective for
– alcohols
– hydrocarbons
– metals
– inorganic minerals
– caustics
how to give activated charcoal
powdered activated charcoal mixed with water
can give with cathartic (sorbitol). Not mineral oil (may interfere with charcoal adsorption)
when to use activated charcoal
drugs that are enterohepatically
recirculated, large amount of substance still in GI tract
can give with cathartic (sorbitol) to remove from GI tract quickly
when not to use activated charcoal
Caustics
Agents with high risk of aspiration (eg, hydrocarbons/petroleum products).
how to give whole bowel irrigation
Large volumes of polyethylene glycol (PEG) solution via nasogastric tube until clear rectal effluent
used for sustained-release medications, agents not adsorbed by activated charcol (metals: Li, Fe, K)
NAC (mucomyst, acetadote) antidote is used for —
acetaminophen poisoning. For best prognosis, treat ASAP. Best if still have 30% of glutathione stores (approx. 8 hrs post ingestion)
Other uses: xylitol, phenol, some mushrooms
Mechanism of action: acts intracellularly as a glutathione substitute, directly binds to NAPQI, precursor for glutathione synthesis
how does NAC (mucomyst, acetadote) antidote work
Mechanism of action: acts intracellularly as a glutathione substitute, directly binds to NAPQI, precursor for glutathione synthesis
antidote for acetaminophen, xylitol, phenol, some mushrooms
adverse reactions of acetadote
bronchospasm (NAC antidote for acetaminophen)
fomepizole (antizol) is used for
antidote for ethylene glycol (EG) or methanol toxicity in dogs
how does fomepizole (antizol) work
Competitively inhibits alcohol
dehydrogenase – this is the enzyme that breaks down ethylene glycol. Most effective if given within 3-6 hours of ingestion,
before metabolism and significant renal damage occurs.
antidote for ethylene glycol or methanol toxicity
adverse reactions of fomepizole (antizol)
Not expected with therapeutic doses. Excess doses can cause CNS depression.
antidote for ethylene glycol (EG) or methanol toxicity in dogs
how to treat ethylene glycol toxicity in cats
fomepizole(antizol) is not efficacious in cats at the doses used in dogs. Much higher doses are needed to inhibit feline alcohol dehydrogenase so use 20% ethanol in cats.
how does ethanol prevent ethylene glycol toxicity
Blocks conversion of toxic alcohols via alcohol dehydrogenase. ETOH has 100x more of an affinity for this enzyme than does EG or methanol.
Adverse reactions: CNS depression, hypoglycemia
Special considerations: 2 protocols: bolus dosing or continuous infusion.
use ethanol in cats and dogs. Use fomepizole in dogs
when to use vit K antidote
for symptomatic (bleeding animals)- give PO or SQ. NOT IV
Do not give as prophylaxis- makes it hard to know when to discontinue treatment
Mechanism of action: reverses the inhibitory effects of coumarin and indanedione derivatives on the synthesis of coagulation factors II, VII, IX and X.
deferoxamine
antidote for iron and aluminum toxicosis
Mechanism of action: Binds iron to form ferrioxamine – this chelate is then excreted through the kidneys
adverse reactions of deferoxamine
- Hypotension (especially if renal impairment) or an anaphylactoid-type reaction (from very rapid iv infusion)
- Yersinia sepsis (deferoxamine promotes the growth of yersinia enterocolitica)
- Pulmonary complications (acute respiratory distress syndrome) with infusions > 24 hrs
Special considerations
– Dosage information not available for cats.
– Do not infuse > 24 hours (reports of severe or fatal pulmonary toxicity when used > 24 hours)
antidote for iron and aluminum toxicosi
where to get antivenins for snake bites
will have North American Pit Vipers and Eastern coral snake (Micrurus fulvis)
can call zoo for more exotic places
mechanism of action for antivenins for snake bite
blocks the venom’s ability to bind to the targeted tissues (binds circulating venom components but also accumulates at the bite site to inactivate locally deposited venom)
— are very sensitive to black widow spider venom (howling, tremor, paralysis).
cats
Dogs are more resistant than cats although they can still develop severe clinical signs.
when to use antivenins for black widow
due to possibility of anaphylaxis, use only in pts with significant neurotoxicity, hemodynamic instability, uncontrolled pain, or prolonged symptomatology
cats are very sensitive
naloxone is used for
for opioid toxicity and the return of adequate, spontaneous ventilation
works as opioid receptor antagonist
Monitor patient for relapse since the narcotic may have a longer duration of action than the naloxone.
bulldog ingests cocaine
Increased salivation, tachycardia (HR 200), febrile (105°) ↑risk for seizures
What method would you use for
decontamination?
depends
prob would not induce vomiting cause of risk of seizure
give activated charcol and diazepam to sedate pt
