Exam one Flashcards
What is the difference between drugs and poisons?
the dose
What are xenobiotics?
foreign chemicals the body doesn’t produce (ex: drugs and poisons)
What is a poison/toxicant?
any substance that when introduced to body can interfere with life processes or biological functions
How is toxicity measured in mammals?
LD50 in mg/kg body weight
How is toxicity measured in birds?
LC50 in mg/kg feed
How is toxicity measured in fish?
LC50 in mg/L h20
What is acute toxicity?
effect of a single dose or multiple doses within 24 hours
What is subacute toxicity?
effect of daily exposure from 1-30days
What is chronic toxicity?
daily exposure for 3 months or more
What is the chronicity factor?
ratio between acute LD50 and chronic LD50
What is the highest nontoxic dose?
largest dose that does not result in undesirable alterations - similar to maximum tolerated dose or minimal toxic dose
What is the toxic dose low?
lowest dose that produces toxic alterations but administering twice does not result in death
What is the toxic dose high?
dose that produces toxic alterations and administering twice the dose results in death
What is the no effect level?
amount of chemical that can be ingested without causing any deaths or illness for any animals in stated period
What is LD0?
highest dose that does not cause death
What is LD50?
dose that kills 50% of animals in group
What is LD100?
lowest dose that kills all animals in a group
How do you measure therapeutic index?
LD50/ED50 smaller value > smaller safety margin
What are the most important routes of toxins?
oral, dermal, inhalation
What is lethal synthesis? Examples?
when the metabolite is more toxic than parent compound ex: organophosphate, ethylene glycol
What is the most efficient barrier in the body? Least?
most = BBB least = placenta
Who assesses drugs?
FDA
Who assesses chemicals?
EPA
What is the equation for the standard safety margin?
(LD1/SD99 - 1) x 100
What is the most important aspect when dealing with toxicosis?
accurate or confirmed diagnosis
What are the criteria of diagnosis?
case history, clinical signs, postmortem findings, chemical analysis, lab animal tests
What drugs are used to induce emesis when indicated?
syrup of ipecac (1/2-2tsp) or hydrogen peroxide 3% (1-2ml/kg)
What are the 4 steps of the treatment of toxicosis?
- supportive/symptomatic treatment
- removal of poison
- specific/antidotal treatment
- observation
What is the best supportive treatment for respiration?
tracheostomy and artificial respiration
What can be given as a bronchodilator?
aminophilline
What is the supportive treatment for the cardiovascular system?
blood/plasma transfusion, fluids for hypovolemia, cardiac stimulants
What drugs can be given as cardiac stimulants?
10% calcium gluconate IV, glucagon IV, digoxin IV
What is the best treatment for acidosis?
sodium bicarb IV, 1/6 molar sodium lactate, lactated ringers
What is the best treatment for alkalosis?
normal saline IV followed by ammonium chloride PO
What is the best treatment for pain?
opioids (fentanyl)
What is the best treatment for CNS depression?
artificial respiration
What is the best treatment for CNS stimulation?
anticonvulsants - diazepam, propoflo, phenobarb
When are emetics used?
within 1-2 hours of ingestion of the poison
What are contraindications of emetics?
unconsciousness, corrosives (bleach), petroleum products, dehydration, convulsions
What is the DOC for emesis in the dog?
apomorphine
What is the antidote for apomorphine?
naloxone IV of levallorphan
What is the DOC for emesis in cats?
xylazine
What are some other choices of emetics?
syrup of epilac, fresh ground mustard, saturated solution of sodium chloride, hydrogen peroxide
What is gastric lavage?
in unconscious ar anesthetized animals, use stomach or ET tube and flush with water and activated charcoal
What is enterogastric lavage?
combination of stomach tube and enema
What are the purgatives?
sodium sulfate, magnesium sulfate, mineral oil
What is used for precipitation?
chemicals that bind the toxicant
What is the precipitant for lead?
sulfate
What is the precipitant for oxalate?
calcium
What is the precipitant for alkaloids?
tannic acid
What is the adsorbent of choice?
activated charcoal
What kind of charcoal is most effective?
plant in small particle size
What is charcoal NOT effective for?
ethanol, methanol, heavy metal salts, fuoride, iodides, nitrate,nitrite, sodium chloride, bleach, fertilizer
What drug decreases the effectiveness of charcoal?
ipecac
What are the most commonly used diuretics?
mannitol (safer) and furosemide
What must be monitored before using diuretics and fluids to enhance elimination?
ensure renal function and hydration of animal
What are examples of urinary acidifiers?
ammonium chloride, methionine
What do urinary acidifiers help excrete?
weak basic drugs ex: alkaloids, amphetamines
What are examples of urinary alkalinizes?
sodium bicarbonate
What do urinary alkalinizes help excrete?
weak acidic drugs ex: NSAIDS, phenobarb
kg > lb
1 kg = 2.2 lb
gal > L > mL
1gal = 4L = 4000mL
qt > L > mL > oz
1qt = 1L = 1000mL = 32oz
pt > mL > oz
1pt = 500mL = 16oz
oz > g
1oz = 30g
fl oz > mL
1 fl oz = 30mL
gr > mg
1gr = 65 or 60mg
m > drop
1m = 1 drop
cup > mL > oz
1 cup = 250mL = 8oz
T > t > mL
1T = 3t = 15mL
t > mL
1t = 5mL
What are the organophosphates?
names that have derivatives of word “phosphorus”
What is the source of organophosphates?
empty pesticide containers, spraying of infectious agents, contaminated feed or drinking water
What is the difference between organophosphates with direct AChE and those without?
those without must be desulfurated before becoming active
How long do organophosphates persist in the environment?
not long 2-4 weeks, can penetrate waxy coatings or skin and live longer
What is storage activation of organophosphates?
become active and more toxic if sealed and stored 1-2years
What are the toxicokinetics of organophosphates?
lipophillic, crosses membranes easily, can absorb through skin or GI or inhaled, well distributed throughout body, enters CNS, no tissue accumulation, tolerance
Which organophosphate is more lipophilic and can sequester in fat and stay in body longer?
dichlorvos
What is lethal synthesis?
when metabolites are more toxic than original compound
Which age of animals are less effected by lethal synthesis?
young animals
What is the MOA of organophosphates?
irreversible inhibition of cholinesterase’s - non-competitive - increases ACh at all cholinergic sites
What is the cause of death in high exposure of organophsphates?
respiratory failure (paralysis), delayed neurotoxicity
What is the onset of action for organophosphates?
rapid 15mins - 1hour
What are the acute clinical sigs of organophosphate toxicity?
muscarinic stimulation, nicotinic stimulation, CNS stimulation, nicotinic blockade > paralysis, coma, dyspnea, death
What is organophosphate induced intermediate syndrome?
with massive doses (malicious) don’t see the initial muscarinic signs and jump right to nicotinic and CNS stimulation
What is organophosphate induced delayed polyneuropathy?
peripheral neurotoxicity after surviving acute poisoning - see muscle weakness, ataxia, 10-14 days after exposure
What is seen on pathology in organophosphate toxicity?
nonspecific lesions - pulmonary edema, hemorrhage, necrosis of skeletal muscle, pancreatitis
How do you test for organophosphates?
stomach/rumen contents, skin from dermal exposure NOT liver/kidney because metabolism is rapid - or look at ACh activity in blood
How do you diagnose organophosphate toxicity?
history of exposure, clinical signs, +/- lab testing, atropine response test (if strong response, probably NOT OP)
What are the DDX for organophosphate poisoning?
pyrethrins, tremorgenic mycotoxins, amitraz toxicosis, blue-green algae, muscarinic mushrooms
How do you treat organophosphate toxicity?
induce emesis (NOT if depressed or seizures), wash with soap water, activated charcoal, supportive care
What should be avoided when treating for organophosphate toxicity?
phenothiazines, aminoglycosides, muscle relaxants, drugs that depress respiration (opioids)
What drugs are used for organophosphate toxicity?
atropine, 2-PAM
What is the antidote for OP toxicity?
2-PAM, pralidoxime, protopam - may not be effective if aging has occurred or against all OP
How do you treat intermediate syndrome in OP?
supportive care, 2-PAM, may last for weeks
How do you treat OP-induced delayed polyneuropathy?
symptomatic therapy only
What is the prognosis for organophosphate toxicity?
lots of factors, mild to moderate generally treatable, acute cases responding to treatment can recover w.i 24 hrs
What are the carbamates?
names contain ‘carb’
Do carbamates undergo storage activation?
NO
What are the pharmacokinetics of carbamates?
does NOT require hepatic bioactivation, more toxic in young patients, fast onset, short duration, low exposure can recover w/o tx, metabolized rapidly
What is the MOA of carbamates?
reversible inhibition of acetylcholinesterase
When does toxicity occur in carbamates?
when carbamylation»_space; hydrolysis
How do you diagnose carbamate toxicity?
measure cholinesterase levels but can give false results since reversible, also not detectable in tissues, blood secretions due to rapid metabolism
What is the treatment for carbamates?
atropine, 2-PAM although not reliable
In what carbamate is 2-PAM contraindicated?
carbaryl, can increase carbamylation process
What are the chlorinated hydrocarbons (organochlorines)?
diphenol aliphatics, aryl hydrocarbons, cyclodienes
When were chlorinated hydrocarbons started?
DDT to control disease vectors, lindane for lice in humans
Are chlorinated hydrocarbons lipophillic or non-lipophillic?
HIGHLY lipophillic –> bioaccumulation in food chain, residues in tissues, persistent in environment
How long do chlorinated hydrocarbons live in the environment?
2-15YEARS
What is the toxicity of chlorinated hydrocarbons like?
low toxicity to mammals, cats most sensitive but all animals susceptible
How are chlorinated hydrocarbons absorbed?
readily absorbed, distributed everywhere
How are chlorinated hydrocarbons excreted?
milk, feces, urine, bile (can be reabsorbed)
How does fat effect the TK of chlorinated hydrocarbons?
acts as a sink, keeps it then redistributes after weeks, months - weight loss can disrupt equilibrium
Because of the biliary excretion, what is a good treatment for chlorinated hydrocarbons?
activated charcoal
What is the MOA of chlorinated hydrocarbons?
Na influx and K efflux in peripheral nerves > partial depolarization of brain> repetitive firing of neuron > axonal hyperactivity
What are the clinical signs of chlorinated hydrocarbon toxicity?
CNS stimulation, repetitive firing, weakness, tremors, spastic gait, seizures
What species shows different clinical signs of chlorinated hydrocarbon toxicity?
birds show CNS depression and blindness
How do you diagnose chlorinated hydrocarbon toxicity?
chemical analysis find in liver, blood or brain in high concentrations - high in fat is not conclusive, no pathognomotic lesions
What is the antidote for chlorinated hydrocarbons?
NONE
How do you treat chlorinated hydrocarbon toxicity?
emesis, wash with soap, activated charcoal, IV lipid therapy, diazepam for seizures, oxygen, fluids
What is the concern about chlorinated hydrocarbons in wildlife?
bioaccumulation and biomagnification, embryo toxicity, thinning eggshells, toxic to aquatics
What are pyrethrins?
extract from flowers - chrysanthemums, also used as an insecticide
What are pyrethroids
synthetic analog of pyrethrins
How long do pyrethrins last in the environment?
NOT long, unstable in air and light
What is different between the 1st and 2nd generation pyrethroids?
gen 1 do NOT have alpha-cyano moiety = less potent
What is the toxicity of pyrethrins like to mammals?
low, no subacute or chronic forms
What species are pyrethrins very toxic to?
fish and some birds - cats more than dogs
Are pyrethrins lipid soluble or non-lipid soluble?
lipid soluble
Where are pyrethrins metabolized?
GIT, plasma and liver - RAPIDLY
Do pyrethrins accumulate in tissues?
NO - no residual effect
How does piperonyl but oxide effect pyrethrins?
inhibits metabolism
What is the MOA of pyrethrins?
delay closure of Na ion channels in axonal membrane of insect, inhibits ATPase leads to repetitive firing
What is the knockdown effect?
rapid paralysis caused by inhibition of neurons -> insect immobile but not dead
What type of pyrethroids have a greater effect?
type 2
Why do pyrethroids effect insects more than mammals?
work better at lower temp, insect Na channels more sensitive and recover slower, insects have slower metabolism
What are some clinical signs of pyrethrin toxicity?
muscle tremors, fine tremors instead of convulsions, depression, ataxia, GI signs, dyspnea, death
How do you diagnose pyrethrins?
no specific lesions, toxins ID in liver and brain, clinical signs with history
What is the antidote for pyrethrins?
NONE
How do you treat pyrethrin toxicity?
wash off, control temp - NO activated charcoal or phenothiazines, treat symptoms, IV lipid therapy
What drug can be given to control muscle tremors in pyrethrin toxicity?
methocarbamol
What can help control seizures in pyrethrin toxicity?
diazepam, barbituates, propofol
Where did rotenone come from?
roots of tropical plants, used for fishing to kill fish
What is rotenone in?
insecticides, home garden supplies, flea/tick treatment, pesticide for chickens, dust on crops
What species is rotenone very toxic to?
fish and cold blooded animals - converted to highly toxic metabolites that are absorbed in gills
Which mammals are most sensitive to rotenone?
pigs - most mammals converted to non-toxic metabolites
What is the absorption of rotenone like?
low and incomplete through GI, inhalation more toxic - fats and oils increase absorption
How is rotenone eliminated?
w/i 24hrs in the feces
What is the MOA of rotenone?
blocks TCA cycle - therefore blocks production of ATP, free radical formation, also anesthetic effect with nerve axons
What are the clinical signs of rotenone toxicity?
local irritation, depression, convulsions
How do you test for rotenone?
look for compound in stomach contents, feces, urine, history
How do you treat rotenone toxicity?
no treatment - supportive tx
What are the sources of D-Limonene?
OTC lice, flea, tick products, essential oil, food fragrant
What is the toxicity of D-Limonene like?
dogs and cats susceptible, cats > dogs
How well is D-Limonene absorbed?
lipid soluble - readily absorbed through GI and skin, wide distribution
What are the clinical signs of D-Limonene toxicity?
ataxia, weakness, paralysis, CNS depression, smell like lemons
How do you diagnose D-Limonene toxicity?
exposure history
How do you treat D-Liminene toxicity?
wash out, monitor temperature
Where does nicotine come from?
alkaloid from dried leaves of nicotiana tabacum, nicotine sulfate is also a plant insecticide
What is the LD50 of nicotine in dogs?
9.2mg - most nicotine products (cigarettes, cigars, patches etc) have a lot above that
How well is nicotine absorbed?
well by inhalation and skin contact but poorly from ingestion unless stomach is alkaline
How is nicotine excreted?
bile and urine
What is the MOA of nicotine?
mimics ACh and stimulates post-synaptic nicotinic receptors, stimulates CRTZ, can block at high doses
What are some clinical signs of nicotine toxicity?
ataxia, hypersalivation, bradycardia, tremors, CNS depression, paralysis of reps muscles > death
How do you diagnose nicotine poisoning?
contents in urine, stomach, kidney, liver, blood - history
How do you treat nicotine toxicity?
emesis, activated charcoal, acidify urine, fluids, NO antacids, atropine, control seizures
What drug is a nonselective nicotinic antagonist used to curb tobacco addiction in humans?
mecamylamine
What is amitraz used for?
preventic collars, swine insecticide, plant insecticide
What species are amitraz products contraindicated in?
cats and horses
What is the acute oral LD50 of amitraz for dogs?
100-150mg/kg
What can increase the toxicity of amitraz?
meperidine, sympathomimetic amines, stress
How is amitraz absorbed?
PO, inhalation, skin
What is the distribution of amitraz?
throughout body including CNS
What is the MOA of amitraz?
A2 adrenergic agonist in CNS, A1 and A2 adrenergic agonist in the ANS, MAO inhibitor
What are the clinical signs of amitraz toxicity?
bradycardia, ataxia, CNS depression, hypothermia, V/D, cardiovascular collapse, respiratory failure
How do you diagnose amitraz toxicity?
chemical analysis of organs, hyperglycemia, history, clinical signs
What are the DDX for amitraz toxicity?
cholinesterase inhibitors, pyrethrins
What is the antidote for amitraz toxicity?
A2 antagonists: yohimbine, atipamezole
What are the treatment methods for amitraz toxicity?
washing, emesis, activated charcoal, cathartics, supportive care, antidote
What is DEET used for?
insect repellant for mosquitos, flies and ticks
What species are susceptible to DEET toxicity?
cats > dogs, young animals more sensitive
How is DEET absorbed?
in skin, accumulates and persists
What is the MOA of DEET?
unknown but causes surface irritation
What are the clinical signs of DEET toxicity?
depression or excitation, ataxia, tremors, seizurees, hypersalivation, vomiting
How do you diagnose DEET toxicity?
20ppm findings in body contents, history, clinical presentation
What is the antidote for DEET toxicity?
none!
How do you treat DEET toxicity?
wash, emesis, activated charcoal, treat symptoms
What is naphthalene found in?
mothballs, organochlorine insecticide
What species are susceptible to naphthalene toxicity?
cats > dogs
How is naphthalene absorbed?
PO, inhalation and oils from skin can absorb
What is the MOA of naphthalene?
irritant, oxidation products cause methemoglobinemia and hemolysis > tissue hypoxia
What are the clinical signs of naphthalene toxicity?
mothball breath, salivation, vomiting, diarrhea, hemolysis, heinz bodies, methemoglobinemia, seizures
How do you diagnose naphthalene toxicity?
hematologic changes - must differentiate from other causes of RBC oxidative injury, measure levels in blood
What is the treatment for naphthalene?
ascorbic acid, methylene blue - emesis, sodium bicarb, supportive care
What is ivermectin in?
a macrocytic lactone, endectocide for heartworm and other parasites
What species are prone to ivermectin toxicity?
dogs, small birds, collies especially
How is ivermectin absorbed?
PO and excreted unchanged in feces
What is the half life of ivermectin?
2 days - go with 5x that to get out of system!
What is the MDR1 gene mutation?
lack of the MDR1 gene > 50x concentration of drug in the CNS
What is the MOA of ivermectin?
GABA agonist
What are the clinical signs of ivermectin toxicity?
CNS depression, ataxia, hypersalivation, coma,
How do you diagnose ivermectin toxicity?
chemical analysis, history, clinical presentation
What is the antidote for ivermectin?
none
How do you treat ivermectin toxicity?
emesis, activated charcoal, picrotoxin, physostigmine, supportive care
What are the 1st generation anticoagulant rodenticides?
warfarin, pindone, chlorophacinone
What are the second generation anticoagulant rodenticides?
brodifacoum, diphacinone, bromodialone
What are the second generation anticoagulant rodenticides used for?
pesticides, baits, powders mixed with food maliciously, eating rats/mice that ingested toxic compounds
What is secondary toxicosis AKA relay toxicosis?
rat dies from toxin, cat eats rat and is effected by toxin
How long do anticoagulant rodenticides last in the environment?
resistant, last weeks to months
What are some properties of anticoagulant rodenticides?
odorless and tasteless, action is slow
Which generation of anticoagulant is more toxic?
2nd gen effective after one dose, 1st gen more toxic when ingested daily for a week
What species are susceptible to anticoagulant rodenticides?
most - pigs, dogs, cats, ruminants, horse, chickens
What can enhance toxicosis of anticoagulant rodenticides?
vit K deficiency, liver dz, enzyme inhibitors, drugs that cause hemorrhage, anemia, etc, steroids or thyroxine
What decreases toxicity of anticoagulant rodenticides?
pregnancy, lactation, enzyme inducers
When do anticoagulant rodenticides reach peak values?
6-12hours
Are anticoagulant rodenticides protein bound?
yes, highly bound
What is the DOA of anticoagulant rodenticides?
3-4 weeks, long half life
Do anticoagulant rodenticides get in milk?
yes, also cross placenta
What is the MOA of anticoagulant rodenticides?
inhibit vit K epoxide reductase, depletes reduced vit K, reduced activation of clotting factors 2,7,9,10
When is the onset of clinical signs for anticoagulant rodenticides?
1-5 days
What are the clinical signs for anticoagulant rodenticide poisoning?
tachypnea, dyspnea, anemia, anorexia, lethargy, hemorrhage, abortion in cattle, death without external evidence of bleeding
What are the pathologic lesions associated with anticoagulant rodenticide toxicity?
bleeding, petechiation, bacterial pneumonia
What is the chemical analysis for rodenticide toxicity?
detection in blood, coagulation parameters
Which test is the earliest indicator of rodenticide toxicity?
PIVKA (sent to lab)
What is the treatment for anticoagulant rodenticides?
RBC, FFP, fluids, oxygen, thoracocentesis -
How do you know if you need to treat anticoagulant rodenticides with FFP or whole blood?
check PCV <15 give blood
What drug is used to treat anticoagulant rodenticide toxicity?
vit K1 PO, bioavailability better after fatty meal, (IV=anaphylaxis, IM=hemmorrhage) won’t work for 24 hours, animals in liver failure may not respond
Which type of vitamin K is used for anticoagulant rodenticide treatment?
K1 NOT K3
When should you recheck the PT in rodenticide poisoning?
Not treating - 36hr and 96hr
treating - 36hr and 48hr
Whats is cholecalciferol used in?
rodenticides, bait, large does of bit D, poisonous plants, human meds/vitamins
Which vitamin is CCF?
D3
What is the solubility of CCF?
insoluble in H20, soluble in most organic solvent and oil
What species are more susceptible to CCF poisoning?
all, young more sensitive
Is vit D toxicity acute or chronic?
can be either depending on preparation
What are some predisposing factors for CCF toxicity?
renal disease, hyperparathyroid, ingestion of lots of calcium and phosphorus
What happens to CCF in the body?
absorbed by GI, binds to serum vitD binding protein, to liver, metabolized to 25 hydroxycholecalciferol (calcidiol) brought to kidney > 1,25 dihydroxycholecalciferol (calcitriol)
How is CCF excreted?
bile, feces, milk (toxic levels)
What is the MOA of CCF?
increases serum calcium due to increased GI absorption, hyperphosphatemia, deposits calcium in soft tissues
What effects does CCF toxicity have?
tissue damage, increased capillary permeability, hemorrhage, loss of sodium and potassium
When do clinical signs of CCF toxicity happen?
24-36 hours
What are the clinical signs of CCF toxicity?
depends on tissues affected - PU/PD, arrhythmias, vomiting, abdominal pain, muscle twitching, seizures, coma, death
What is the main lesion associated with CCF toxicity?
hemorrhagic gastroenteritis
What does the lab work look like of an animal with CCF toxicity?
hypercalcemia, hyperphosphatemia, elevated serum 25 hydroxy and 1,25 dihydroxycholecalciferol, decreased iPTH
How do you diagnose CCF toxicity?
history, clinical signs, lab, calcification of tissues
How do you treat CCF toxicity?
emetics, activated charcoal, saline cathartic, normal saline, furosemide, glucocorticoids, calcitonin, pamidronate disodium, low Ca diet, stay out of sun
Where does bromethalin come from?
general use pesticide, bait
What animals are sensitive to bromethalin toxicity?
cats > dogs, g-pigs are resistant!
How is bromethalin absorbed and distributed?
hgihly lipophilic, absorbed PO, widely distributed, highest in brain and fat
What is bromethalin metabolized to?
more toxic metabolite desmethylbromethalin in liver
How is bromethalin excreted and what is the half life?
5-6 days, in bile, urine
What is the MOA of bromethalin?
uncoupling of oxidative phosphorylation, lack of adequate ATP, insufficient energy for Na/K ion pumps, cerebral and spinal cord edema
Which part of the body is the main target in bromethalin poisoning?
brain/CNS
When do signs of toxicity occur with bromethalin?
acutely 2-24hrs, subacute 2-3 days
What are the clinical signs of bromethalin toxicity?
muscle tremors, hyperthermia, seizures, ataxia, paralysis, hyperreflexia, UMN bladder
What lesions are found in bromethalin toxicity?
cerebral edema, diffuse white matter vacuolization in CNS
How do you diagnose bromethalin toxicity?
history, clinical signs, brain imaging of white matter vacuolization in CNS, chemical analysis TAT 5-7days
What is the antidote for bromethalin toxicity?
none
How do you treat bromethalin toxicity?
emetic, activated charcoal, saline cathartic, mannitol, diazepam, supplemental feeding
What is strychnine in?
restricted use pesticide to control gophers and squirrels, ingest bait or relay toxicosis
What does strychnine come from?
strychnos seeds, bitter taste, poorly water soluble, white powder
How long does strychnine live in the environment?
gone from soil w/i 40 days
What species are susceptible to strychnine toxicity?
dogs, horses, cattle, pigs > cats
What species are resistant to strychnine toxicity?
poultry
What can decrease toxicity of strychnine?
committing, food in stomach, small amt over time
How is strychnine absorbed?
from GI > crosses BBB > liver
How is strychnine eliminated?
urine
Is strychnine PP bound?
NO
How soon is strychnine eliminated?
w/i 24 hours
What is the MOA of strychnine??
blocks postsynaptic effect of inhibitory glycine in spinal cord leading to highly exaggerated reflex arcs
When is the onset of strychnine toxicity?
15min - 2hr, rapid death
What are the clinical signs of strychnine poisoning?
panting, vomiting, mydriasis, stiffness, muscle twitches, seizures, death by respiratory failure
What lab samples can be tested for strychnine poisoning?
urine, stomach contents, liver
How do you diagnose strychnine toxicity?
history, clinical signs, lab
How do you treat strychnine toxicity?
apomorphine for emesis, gastric lavage, activated charcoal, symptomatic treatment
What is contraindicated in the lavage for strychnine toxicity?
sodium bicarbonate, antacids
What drugs are used for symptomatic treatments of strychnine poisoning?
pentobarbitol, diazepam, methocarbamol, guaifenesin, xylazine
What is zinc phosphate used for?
restricted use pesticides, phosphine gas, baits, poisoned rodents
Is zinc phosphate stable in the environment?
stable when dry, decomposes on air or bait w/i 2 weeks, insoluble in H20
What type of zinc phosphide leads to acute toxicity?
acute from phosphine gas, chronic from either phosphine gas OR zinc phosphide
What enhances zinc phosphide toxicity?
gastric acid - causes hydrolysis of zinc phosphide to phosphine gas at pH 4 or lower
How are zinc phosphides absorbed?
in GI tract and inhalation, - GI irritant (skin insignificant)
how is absorbed phosphine excreted?
lungs , urine
What is the MOA of zinc phosphide?
unknown - increases oxygen radicals and direct GI irritation, damage to blood vessels
What are the main tissues affected by zinc phosphide toxicity?
brain, heart, kidney, liver, lung
What are the clinical signs of zinc phosphide toxicity?
anorexia, vomiting, increased rate and depth of respiration, abdominal pain, bloat, dyspnea, death, CNS stimulation in dogs, yelping and convulsions
What is the onset like of zinc phosphide?
rapid - mins to hours
Why does death occur in zine phosphide toxicity?
tissue anoxia
What are the classic lesions of zinc phosphide toxicity?
odor of rotten fish/garlic, hemorrhagic gastroenteritis, congestion of liver and kidney, pulmonary edema
What does the lab work show in zinc phosphide toxicity?
elevated serum zinc, metabolic acidosis
How should specimens of zinc phosphide toxicity be contained to send to lab?
rapidly frozen
How do you diagnose zinc phosphide toxicity?
history, acetylene odor, clinical signs, rapid onset/death, lab diagnosis
Does zinc phosphide pose a risk to hospital staff?
YES! if smelling it at 2ppm (safe limit is 1ppm)
What is the antidote for zinc phosphide toxicity?
none
What is the treatment for zinc phosphide?
emetics, gastric lavage, PO antacids, activated charcoal, IV fluids, O2, circulatory and pulmonary support,
Where does fluoroacetate come from?
called compound 1080, used to control coyotes, and rodents, collar worn by sheep and goats
How do animals get fluoroacetate poisoning?
eating poisoned rodents, eating plants that contain fluoroacetate
Doe fluoroacetate survive long in the environment?
chemically stable but degraded by soil microorganisms and plant enzymes, odorless and water soluble but insoluble in most organic solvents
What species are effected by fluoroacetate toxicity?
dogs > mammals
How is fluoroacetate absorbed?
GI tract, lungs, open wounds but NOT intact skin
How is fluoroacetate excreted?
in urine
What is the MOA of fluoroacetate?
condenses w/ oxaloacetate and competes w citrate for active site of CAC - slows the CAC, decreases respiration and energy, buildup of citrate
Which organs are most effected by fluoroacetate toxicity?
brain (ammonia buildup) and heart
What are the clinical signs of fluoroacetate toxicity?
rapid onset of GI hyperactivity, CNS stimulation, hyperthermia, heart failure, colic, convulsions
What lesions are associated with fluoroacetate toxicity?
rapid rigor mortis, cyanosis, hemorrhages, pulmonary changes, organ congestion
What does the lab work show in fluoroacetate toxicity?
elevated citrate, hyperglycemia, metabolic acidosis, ionized hypocalcemia
How do you diagnose fluoroacetate toxicity?
history, clinical signs, lesions
How do you treat fluoroacetate toxicity?
activated charcoal, with rapid onset tx may not be an option
What is the antidote for fluoroacetate toxicity?
acetate
What drugs can be given in fluoroacetate poisoning?
calcium chloride for ventricular arrhythmias, sodium bicarb for metabolic acidosis, oxygen, fluids
How do animals get water deprivation?
feedining brine, whey or garbage, ingestion of salt licks, drinking water containing salt, overcrowding, frozen water, lack of water, medicated (unpalatable) water
What effect does salt have on animals?
taste is attractive, mild irritant to mucous membranes
How much salt can animals tolerate in feed?
> 10% salt in feed if they have free access to water
What species are susceptible to water deprivation?
pigs, cattle and poultry mostly, dogs less
How is salt absorbed?
by GI and distributed all over body - enters brain by passive diffusion and removed by active transport
How is excess sodium excreted?
in urine, as long as there is enough water
What is the MOA of water deprivation?
dehydration increases plasma sodium and cerebral spinal fluid - high sodium in brain inhibits anaerobic glycolysis resulting in lack of energy for active transport
What happens with sodium trapped in the brain?
attracts water because of osmotic gradient > cerebral edema and brain damage
What are the clinical signs of water deprivation?
early constipation and thirst, vomiting, PU, metabolic acidosis, seizures, circling, head pressing, blindness
What lesions are seen in water deprivation that are pathognomonic?
eosinophilic meningoencephalitis is pathognomonic in PIGS ONLY and only within 24 hours of exposure - disappears after
What other lesions could be seen with water deprivation?
fluid in body cavities, organ edema, cerebral edema
What is used for lab diagnosis of water deprivation?
serum and CSF concentrations, salt in feed
How do you diagnose water deprivation?
history, encephalitic signs, lesions and lab diagnosis
How do you treat water deprivation?
give small amounts of fresh water - large amount can kill them by causing more cerebral edema, IV fluids, furosemide, anticonvulsants
What is the prognosis of water deprivation?
poor, mortality 50%
What is the source of acute copper toxicosis?
ingestion of high concentrations of copper - feed additives, in soil
Why is acute heavy metal toxicity bad?
very small amount can cause toxicosis, irritants, poor penetrated of membranes, small amount that is absorbed can cause toxicosis because of potency
Which heavy metal crosses the BBB and causes CNS damage?
lead
What are the clinical signs of acute copper toxicosis?
rapid onset of GI signs, dehydration, shock
What species is chronic copper poisoning common in?
sheep > cattle, due to lower maliptinum in sheep that enhance copper toxicosis
What is the treatment for acute copper toxicosis?
supportive and symptomatic therapy
What enhances excess copper in the body?
molybdenum deficiency