Insecticides Flashcards
When was the first organophosphate synthesized?
1854
What was one of the earliest OP insecticides?
Parathion
More toxic versions of parathion were developed when?
During WWII
Thousands of organophosphates have been synthesized in an attempt to do what?
Find species-selective compounds to reduce mammalian toxicity.
T/F: There are several types of organophosphates.
True
Name 3 organophosphates that have direct Acetylcholinesterase activity?
- Dichlorvos
- Monocrotophos
- Trichlorfon
Name 4 organophosphates that must be desulfurated before they become active.
- Bromophos
- Diazinon
- Fenthion
- Parathion
What is the average amount of time organophosphates persist in the environment?
2-4 weeks
Name 4 organophosphates that are subject to “storage activation”.
- Parathion
- Malathion
- Diazinon
- Coumaphos
What is storage activation?
If sealed & stored 1-2 years, becomes more toxic.
What “grade” of organophosphate is more toxic?
What are 2 reasons why?
- Technical grade.
- Heat isomeration, impurities
Which is more likely to be readily absorbed from the GIT, skin and mucous membranes or by inhalation: a toxin that is lipophilic or hydrophilic?
Lipophilic
What is the most common type of exposure for organophosphates?
Oral exposure (contaminated feeds)
What are 3 possible routes of exposure for organophosphates?
- Oral (contaminated feed)
- Dermal (dip/spray)
- Inhaled (recent aerial spray)
Are organophosphates well distributed throughout the body?
Yes
Can organophosphates affect the CNS?
Yes
Is there significant tissue accumulation with organophosphates?
No
What is an example of an organophosphate that is more lipophilic than average, meaning it can sequester more in fat and stay in the body longer?
Dichlorvos
Where are organophosphates metabolized?
Liver
Toxins that require desulfuration are activated by liver metabolism in a process known as what?
“Lethal synthesis”
Is “lethal synthesis” less toxic in young or old patients?
Why?
- Young
- Liver metabolism is not completely developed in the young.
Organophosphates that require desulfuration by the liver to be activated are made more toxic if what are present?
What is an example of one?
- Enzyme inducers
- Phenobarbital
Continued exposure to organophosphates can lead to what?
What are 3 reasons for this?
- Tolerance
- Enzyme induction, functional adaptation to decreased esterases, adaptation of ACh receptors to excessive amounts of ACh
Adaptation of ACh receptors to excessive amounts of ACh is known as what?
Receptor down-regulation
What is the mechanism of action for organophosphates?
Irreversible inhibition of cholinesterases
Do organophosphates increase or decrease ACh at all cholinergic sties?
Increase
Which receptors do organophosphates stimulate first?
Muscarinic receptors
Which receptors do organophosphates stimulate second?
Nicotinic receptors
What is the last receptor effect that organophosphates have?
Nicotinic blockade
What happens in a nicotinic blockade?
Eventually depolarizes to the point it can’t repolarize.
What is the cause of death with high exposure to organophosphates?
Respiratory failure/paralysis
What is another name for the delayed neurotoxicity possible with organophosphates?
OP induced delayed polyneuropathy
How quick is the onset of clinical signs seen with acute organophosphate toxicity?
15 mins - 1 hr
What is the initial clinical sign seen with organophosphate toxicity?
Muscarinic stimulation
Muscarinic stimulation can cause DUMBBELLS, which stands for what?
D - diarrhea U - urination M - myosis B - bronchoconstriction B - bradycardia E - emesis L - lacrimation S - salivation
Muscle fasciculation, tremors, twitching, spasm, hypertonicity and stiff gait can be seen with the stimulation of what kind of receptors by organophosphates?
Nicotinic receptors
Anxiety, restlessness, hyperactivity, may proceed to tonic-clonic seizures when what is stimulated?
CNS
Paralysis, CNS depression, coma, dyspnea and death due to respiratory failure can be cause by what type of blockade?
Nicotinic blockade
What can be seen with massive (malicious) doses of organophosphates?
OP induced intermediate syndrome
T/F: No muscarinic signs or muscle fasciculations are seen with OP induced intermediate syndrome.
True
What type of exposure can lead to OP induced intermediate syndrome?
Chronic exposure
What can occur if acute poisoning with an organophosphate happens?
OP induced delayed polyneuropathy
What are 3 signs of OP induced delayed polyneuropathy?
- Muscle weakness
- Ataxia
- Rear limb paralysis
How long does it take after exposure for OP induced delayed polyneuropathy to develop?
10-14 days
Distal degeneration of long/large diameter motor and sensory axons of peripheral nerves and spinal cord can occur with what?
OP induced delayed polyneuropathy
What species is most sensitive to OP induced delayed polyneuropathy?
Chickens
Are there any specific lesions with acute death associated with organophosphates?
No
Dogs exposed to more lipophilic organophosphates can have what condition develop?
Pancreatitis
How are organophosphates diagnosed?
Direct detection
Residues of which organophosphate may be seen in samples from fat or liver tissue?
Chlorpyrifos
What is something that can be tested antemortem to detect organophosphate toxicity?
Acetylcholinesterase activity level
How soon does a sample for organophosphate toxicity need to be assessed?
ASAP to preserve activity.
Less than what percentage of acetylcholinesterase activity is considered suspicious in suspected OP toxicity?
What percentage is considered diagnostic?
-
What are 3 things to be considered for clinical diagnosis of OPs?
- History of exposure
- Clinical signs
- Lab testing
If a strong response to a low dose (0.02mg/kg) of this drug is seen, then it is less likely to be OP toxicity.
Atropine
Should emesis be induced with OP toxicity?
Only if recent. Not if depressed or seizures.
What can be done with dermal exposure to OPs?
Wash gently with tepid, soapy water.
Can activated charcoal be used for OPs?
Yes
What are 4 things that should be avoided with OP toxicity?
- Phenothiazines
- Aminoglycosides
- Muscle relaxants
- Drugs that depress respiration (opioids)
What drug can be used to treat OP toxicity?
What is the MOA?
Doses?
- Atropine
- Specific physiologic antagonist
- SA/horses: 0.2 mg/kg
Food/LA: 0.5mg/kg
Give 1/4 dose IV then rest IM or SC, repeat 3-6 hr based on clinical response.
What is the most effective treatment of OP toxicity in acute cases?
Dose?
- 2-PAM (Pralidoxime, Protopam)
- 25-50 mg/kg 10% solution slow IV
Is 2-PAM effective against all OPs?
No
2-PAM may not be effective if what has occurred?
Aging
What is “aging”?
OP bound for a long time, changes chemically so that 2-PAM can no longer pull it off.
What is the main form of treatment with OP intermediate syndrome?
Supportive care
Is atropine more or less effective with OP intermediate syndrome compared to acute toxicity?
Less effective
With OP intermediate syndrome, 2-PAM should be reserved for what type of cases?
Severe cases
What is the treatment for OP induced delayed polyneuropathy?
Symptomatic therapy
Prognosis for OP toxicity is better if patient is what?
Alive
What are 2 determiners of prognosis for OP toxicity?
- Dose
- How long since exposure
Mild to moderate signs with OP toxicity are generally what?
Treatable
Acute cases of OP toxicity that respond to treatment can recover within what time frame?
24 hours
What is an example of a carbamate?
Carbaryl (Sevin)
What is something that carbamates do not undergo that OPs do?
Storage activation
Do carbamates require hepatic bioactivation?
No
Which has a faster onset: OPs or carbamates?
Shorter duration of action?
- Carbamates
- Carbamates
T/F: A low exposure to carbamates may recover without treatment.
True
Are carbamates metabolized slowly or rapidly?
Very rapidly
What is the MOA of carbamates?
Reversible inhibition of acetylcholinesterase
What can be tested in the lab when looking for carbamate toxicity?
Cholinesterase levels
What can happen if a sample for carbamate testing is not tested fast enough?
False negative due to reversible binding.
What drug is used to treat carbamates?
Atropine
Is 2-PAM a good choice for carbamates?
Why?
- No
- Reversible binding reduces benefit.
Which carbamate is 2-PAM contraindicated with?
Why?
- Carbaryl (Sevin)
- Can potentially increase carbamylation process.
What happens with a high dose exposure of carbamates?
Animal dies too quickly for treatment.
What happens with a low dose exposure of carbamates?
Animal may survive without treatment if signs are not severe.
What type of insecticide are Diphenyl aliphatics (DDT, methoxychlor?
Chlorinated hydrocarbon (Organochlorine)
What type of insecticide are aryl hydrocarbons (Lindane)?
Chlorinated hydrocarbon (Organochlorine)
What type of insecticide are cyclodienes (Aldrin, Toxaphene)?
Chlorinated hydrocarbon (Organochlorine)
What insecticide was banned in the USA in 2003?
Methoxychlor
Are chlorinated hydrocarbons lipophilic or hydrophilic?
Highly lipophilic
Are chlorinated hydrocarbons soluble in water?
No
The lipophilic nature of chlorinated hydrocarbons leads to what?
Bio-accumulation in the food chain.
What is the soil half-life of chlorinated hydrocarbons?
2-15 years
Which can survive longer in the environment: organophosphates or chlorinated hydrocarbons?
Chlorinated hydrocarbons
Which species is more sensitive to chlorinated hydrocarbons: dogs or cats?
Cats
Do chlorinated hydrocarbons generally have a low or high toxicity to mammals?
Low
Which animals are susceptible to chlorinated hydrocarbons?
All animals
Are chlorinated hydrocarbons readily absorbed?
Yes - highly lipophilic
Do chlorinated hydrocarbons cross into the CNS?
Yes
T/F: Chlorinated hydrocarbons undergo metabolism by liver microsomal enzymes.
True
Do the metabolites of chlorinated hydrocarbons undergo enterohepatic recycling?
Yes
What are 4 ways the metabolites of chlorinated hydrocarbons can be excreted from the body?
- Milk
- Feces
- Urine
- Bile
What is the half-life of chlorinated hydrocarbons?
Weeks to months
What can disrupt equilibrium and allow a large amount of chlorinated hydrocarbon metabolites to be released into the blood stream?
Weight loss
What is the main clinical sign for chlorinated hydrocarbon toxicity?
CNS stimulation
Some mammals can show what instead of typical CNS excitability with chlorinated hydrocarbon toxicity?
Intermittent or persistent depression
Which species may show depression, abnormal postures, apparent blindness and death with chlorinated hydrocarbon toxicity?
Birds
Which species can have seizures as a result of chlorinated hydrocarbon toxicity?
Cattle
Are there any specific pathological lesions for chlorinated hydrocarbons?
No
Acute chlorinated hydrocarbon toxicity can be confirmed if insecticide is in what 3 types of samples at significant concentrations?
- Blood
- Liver
- Brain
A diagnosis of chlorinated hydrocarbon toxicity is made with what 4 factors?
- History of exposure
- Clinical signs
- Lack of specific lesions
- Chemical analysis of tissues
Compared to cholinesterases, chlorinated hydrocarbon toxicity has less or more parasympathetic signs?
CNS stimulation?
- Less parasympathetic signs
- More severe CNS stimulation (convulsive seizures)
Is there any specific antidote for chlorinated hydrocarbon toxicity?
No
What are 3 forms of decontamination that can be used with chlorinated hydrocarbons?
- Induce emesis (if indicated)
- Wash soap/water if dermal exposure
- Activated charcoal (better) or mineral oil
What 2 drugs can be given to help control seizures caused by chlorinated hydrocarbon toxicity?
Diazepam or barbiturates
What are 3 types of symptomatic treatment that can be given with chlorinated hydrocarbon toxicity?
- Oxygen
- Ventilation
- Fluids
What is the prognosis for chlorinated hydrocarbon toxicity?
What are 2 factors this depends on?
- Guarded to good
- Dose, early detoxification
What toxin can lead to embryo toxicity and eggshell thinning in raptors?
Chlorinated hydrocarbons
What toxin can by toxic to aquatic wildlife and some amphibians?
Chlorinated hydrocarbons
What is an example of a pyrethrum flower from which pyrethrins can be extracted?
Crysanthemum cinerariaefolium
What are synthetic analogs of pyrethrins known as?
Pyrethroids
Which type of toxin is unstable in air and light which both cause it to break down quickly?
Pyrethrins/Pyrethroids
What are 6 examples of natural pyrethrins?
- Pyrethrin I & II
- Cinerin I & II
- Jasmolin I & II
What are 2 types of synthetic pyrethrins?
- First generation/Type 1
- Second generation/Type 2
What do second generation/Type 2 synthetic pyrethrins contain that first generation/Type 1 do not?
What does this do?
- Alpha-cyano moiety
- Increases their insecticidal potency
Is the overall toxicity low or high in mammals?
Low
What two forms of toxicity are not found with pyrethrins/pyrethroids?
Which one is?
- Subacute or chronic
- Acute
What two species are pyrethrins/pyrethroids very toxic in?
- Fish
- Some birds
Are cats more or less sensitive than dogs to pyrethrins/pyrethroids?
More
Are pyrethrins/pyrethroids lipid soluble?
Yes
What is the most common type of exposure seen with pyrethrins/pyrethroids?
What are 2 other possible forms of exposure?
- Dermal
- Ingestion & inhalation
Where are 3 locations pyrethrins/pyrethroids can be rapidly metabolized?
- GIT
- Plasma
- Liver
How are conjugated metabolites of pyrethrins/pyrethroids excreted?
Urine
The presence of alpha-cyano moiety (Type 2) decreases the rate of what?
Hydrolysis
Do pyrethrins/pyrethroids accumulate in tissues?
No
What can be added to pyrethrins/pyrethroids that acts as a synergist?
What does it do?
- Piperonyl butoxide or MGK-264
- Inhibits pyrethrin metabolism by insects
Generalized muscle tremors, depression, blindness (reversible) and ataxia are clinical signs that can be seen with which category of toxin?
Pyrethrins/pyrethroids
With pyrethrin/pyrethroid toxicity, some dogs can show what which may occur as a topical hypersensitivity reaction or firing of sensory peripheral nerves?
“Acute paralysis” which is actually paresthesia (abnormal sensation of prickling, itching)
Are there any specific pathological lesions seen with pyrethrins/pyrethroids?
No
Are pyrethrins/pyrethroids easy or difficult to detect in tissue samples?
Difficult
T/F: Tissue levels of pyrethrins/pyrethroids correlate well with severity of clinical signs.
False - Tissue levels do not correlate well with severity of clinical signs.
What 3 factors are used to make a diagnosis of pyrethrin/pyrethroid toxicity?
- History of exposure
- Appropriate clinical signs
- Ruling out other causes
Is there any specific antidote for pyrethrin/pyrethroid toxicity?
No
For which category of toxin is activated charcoal generally not used?
Pyrethrins/pyrethroids
It is important to monitor and control what with pyrethrin/pyrethroid toxicity?
Temperature (hypothermia)
With pyrethrin/pyrethroid toxicity that has very mild signs, what is the treatment?
Decontamination
If there are severe muscle tremors seen with pyrethroid/pyrethrin toxicity, what can be given for treatment?
Methocarbamol
What are 3 drugs that can be given for seizures seen with pyrethrin/pyrethroid toxicity?
- Diazepam
- Barbiturates
- Propofol CRI
What is the prognosis for pyrethrin/pyrethroid toxicity?
Generally very good
What is one of the oldest botanical insecticides?
Rotenone
What is a common use of rotenone in pets?
Treatment of lice, ticks, mites
Rotenone is very toxic to what 2 species?
- Fish
- Cold-blooded animals
Which mammal species is more sensitive to rotenone?
Pigs
Which is more toxic with rotenone: inhalation or ingestion?
Inhalation
Low and incomplete absorption of rotenone is seen where in the body?
GIT
Do fats/oils increase or decrease the absorption of rotenone?
Increase
Which formulation of rotenone is highly toxic relative to other formulations?
Emulsified concentrate
What is rotenone converted to in fish/insects?
In mammals?
- Toxic metabolites
- Non-toxic metabolites
How long does it take for rotenone to be eliminated?
In what form?
- 24 hours
- Feces
Which toxin is an irritant that can cause local irritation such as conjunctivitis, congestion, dermatitis, GI upset if ingested?
Rotenone
What are the 2 predominate clinical signs seen with rotenone?
- Depression
- Convulsions
What are 3 things that can be seen antemortem with lab testing for rotenone toxicity?
- Hypoglycemia
- Liver changes
- Hypoxemia/hypercapnea
Diagnosis of rotenone toxicity is based on what?
History and documentation of compound
Are there any specific treatments for rotenone toxicity?
No
What are 2 things that can be done for rotenone toxicity?
- Detoxification
- Supportive care
What is the prognosis for rotenone toxicity in mammals?
In fish/reptiles?
- Generally good
- Poor
What is the main source of D-Limonene?
OTC products for control of lice, fleas ticks (usually shampoos)
What are 3 things D-Limonene can be combined with?
- Other essential oils
- Piperonyl butoxide
- Enzyme inhibitors
D-Limonene is toxic to the flea at which life stages?
All life stages
Which species is more sensitive to D-Limonene: dogs or cats?
Cats
What is seen in cats with D-Limonene toxicity at:
5x recommended dose?
15x recommended dose?
- Mild toxicity
- Severe signs lasting 5 hours
Is D-Limonene lipid soluble?
Yes
D-Limonene can reach maximal blood concentration how long after dermal exposure?
10 mins
Does D-Limonene have wide distribution in the body?
Yes
Where is D-Limonene metabolized?
Excreted?
- Liver
- Urine
What is a patient with D-Limonene toxicity said to smell like?
Lemons
Are there any specific pathological lesions for D-Limonene toxicity?
No
Is there any specific lab testing available for D-Limonene toxicity?
No
What 2 things are D-Limonene toxicity based on?
- Exposure history
- Scent of patient
What are 3 forms of treatment for D-Limonene toxicity?
- Decontamination
- Monitor temperature (iatrogenic hypothermia)
- Supportive care (fluids, etc.)
What is the prognosis for sub-lethal D-Limonene toxicity?
Excellent
Sub-lethal D-Limonene toxicity usually resolves in what time frame?
6-12 hrs
Prognosis for D-Limonene toxicity is worse if there is what?
Skin reactions
What is one of the most common essential oils encountered?
What is it used for?
- Melaleuca oil (tea tree oil)
- Topically for flea control
Parts of the plant from which nicotine is derived are teratogenic to what 2 species?
- Sows
- Cattle
T/F: Nicotine is highly toxic to dogs.
True
What is the oral LD50 of nicotine in dogs?
At what dose can clinical signs be seen?
- 9.2 mg/kg
- 1 mg/kg
What other ingredient might nicotine gum contain that is also toxic to dogs (but not humans or cats)?
Xylitol
Nicotine is absorbed well through what 2 routes of administration?
- Inhalation
- Intact skin
Through what route of administration is nicotine poorly absorbed?
Ingestion
What would increase absorption of nicotine in the stomach?
What do you not give a dog with GI signs?
- Alkalinization of the stomach.
- Antacids
Where is nicotine metabolized?
Excreted?
- Liver
- Bile & urine
Which route of excretion is decreased with an alkaline pH?
Why?
- Renal excretion
- Increases reabsorption
What clinical sign is seen in 25% of nicotine toxicity cases?
Ataxia
What clinical sign can be seen within 1 hour or exposure to nicotine?
Tremors
What are 3 clinical signs that can be seen with higher doses?
- CNS depression
- Tachycardia
- Vasodilation
Is the clinical course of nicotine toxicity slow or rapid?
Rapid (mins to hours)
A patient that smells like an old cigar might have what type of toxicity?
Nicotine
What are 5 areas that can be tested for nicotine?
- Urine
- Stomach contents
- Kidney
- Liver
- Blood
Nicotine at low doses may resemble what?
Higher doses/later stages?
- Cholinesterase inhibitors ( OP/Carbamate
- CNS depressants
What are 2 forms of decontamination that can be used with nicotine toxicity?
- Induce emesis
- Activated charcoal
What should be avoided in treatment of nicotine toxicity?
Antacids
What are 2 ways to enhance the excretion of nicotine?
- IV fluids
- Acidification of urine
What can be given to treat parasympathetic effects seen with nicotine toxicity?
Atropine
This is a foramidine insecticide/acaracide (ticks/mites).
Amitraz
How does Amitraz work on ticks/mites?
Paralyzes the mouth parts.
Where can amitraz be found?
Flea/tick collars
What is amitraz used for in swine and cattle?
Miticide/insecticide
Amitraz is not labeled for use in what 2 species?
- Cats
- Horses
This toxin is a mild irritant and concentrates are flammable.
Amitraz
What is the acute oral LD50 of amitraz for dogs?
250 mg/kg
What type of signs can be seen in dogs with 20 mg/kg of amitraz?
Mild signs/sedation
What are 2 drugs that can increase the toxicity of amitraz?
- Meperidine (Demerol)
- Sympathomimetic amines
What are 4 things that can increase the toxicity of amitraz?
- Stress
- Debilitation
- Advanced age
- Toy breeds
Amitraz is readily absorbed by what route?
What are 2 other routes it can be absorbed through?
- Oral
- Inhalation, Skin
Peak plasma concentrations of Amitraz can be seen when?
Elimination half-life?
- After 5 hours
- 24 hours
Is amitraz well distributed throughout the body?
Yes
Where is amitraz rapidly metabolized?
Excreted?
- Liver
- Urine
What is the most common clinical sign seen with amitraz?
How long is it seen?
- Transient sedation
- 24-72 hours
What can be seen with amitraz toxicity due to alpha-2 inhibition of insulin?
Hyperglycemia
Are there any specific pathological lesions for amitraz?
No
Can tissue be analyzed for amitraz?
Yes
What are 3 factors for diagnosing amitraz toxicity?
- History
- Clinical signs
- Specific analysis
What is the most significant differential diagnosis for amitraz toxicity?
CNS depressants
What is the antidote for amitraz toxicity?
What are 2 examples?
- Alpha-2 antagonists
- Yohimbine (short acting), Atipamezole ( few cardio-respiratory effects than yohimbine)
What is the prognosis for amitraz toxicity?
Pretty good
Wht is thechemical nof N,N-diethyl-m-tolumide?
DEET
DEET is used for the control of what 3 things?
- Mosquitoes
- Flies
- Ticks
What are 2 other insecticides that DEET can be combined with?
- Fenvalerate
- Pyrethroid
The concentration of DEET can range from what to what?
What is the typical amount in pet products?
- 5-100%
-
Which toxin has a characteristc sweet odor?
DEET
Which toxin may damage synthetic fibers or plastics?
DEET
Which species is more sensitive to DEET, cats or dogs?
Cats
Which are more sensitive to DEET, young or old animals?
Young
What might increase the toxicity of DEET?
CNS depressants
What pecenage of DEET is absorbed from the skin in dogs?
7.9-12.8%
Where in the body can DEET accumulate and persist?
Skin
Which insecticide can increase dermal absorption of others?
DEET
Where is DEET metabolized?
Excreted?
- Liver
- Urine
With DEET, depression, excitiation, ataxia, tremors, seizures and coma are clinical signs in what 2 species?
- Rabbits
- Rats
With DEET, hypersalvation, vomiting, hyperexcitibility, tremors, ataxia and seizures are clinical signs that can be seen with what 2 species?
- Dogs
- Cats
Are there any specific patholgical lesions for DEET toxicity?
No
What amount of DEET is considered diagnostic?
Considered supportive?
- 20 ppm
- Urine > 1ppm, Tissue >10ppm
What are 4 other CNS excitatory toxins DEET must be differentiated from?
- Strychnine
- Metaldehyde
- Organochlorine
- OP/carbamate
Are there any specific antidotes for DEET toxicity?
No
What are 3 forms of decontamination that can be used for DEET toxicity?
- Dermal exposure: wash soap/water
- Emesis
- Activated charcoal +/- cathartic (avoid magnesium cathartic)
What is the main form of treatment for DEET toxicity?
Symptomatic treatment
What is the prognosis for sublethal DEET toxicity?
Usually respond in 24-72 hrs
What is the most common source of naphthalene?
Mothballs
Newer mothballs contain what instead of naphthalene?
Paradichlorobenzene
How do you tell if you have old fashioned mothballs with naphthalene?
Put in water, mothballs with naphthalene will float, those with paradichlorobenzene will sink.
What naphthalene derived from?
Coal tar/petroleum hydrocarbons
What happens to naphthalene at room temp?
Sublimates - go from a solid directly to a gas
Which are more sensitive to naphthalene toxicity, cats or dogs?
Cats
Which are more susceptible to naphthalene toxicity, cats or dogs?
Dog - more likely to ingest
What is the lowest canine lethal dose for naphthalene toxicity?
400 mg/kg
How many mothballs can be toxic to a dog?
1 or 2
What are 3 ways naphthalene can be absorbed?
- Oral
- Inhalation
- Intact skin
What are 2 things that can be caused by the oxidation products of naphthalene?
- Methemoglobinemia
- Hemolysis
What is a common clinical sign of naphthalene ingestion?
Mothball breath
Which insecticide can cause heinz bodies?
Naphthalene
Hepatic injury and secondary renal injury can occur with which insecticide?
Naphthalene
What clinical sign can occur in neonates due to naphthalene toxicity?
Cataracts
What do you need to differentiate the characteristic hematologic changes seen with naphthalene from?
What are 3 examples?
- Other causes of RBC oxidative injury
- Acetaminophen, onions, nitrates
Which species RBCs are more susceptible to oxidative injury than other species?
Cats
What are 2 specific treatments for naphthalene toxicity?
Which is faster?
- Ascorbicaci (20 mg/kg)
- Methylene blue 1%
- Methylene blue 1%
What can be used to reduce precipitation of Hgb in the kidneys due to naphthalene toxicity?
Sodium bicarbonate
What is the prognosis for naphthalene toxicity?
Reasonable if treated promptly
What type of insecticide is ivermectin?
Macrocytic lactone
What is ivermectin used for in dogs and cats?
Prevention of heartworm
Ivermectin toxcity is usually caused by what?
Overdose
What is a potential source of ivermectin exposure in dogs?
Horse feces
What are 2 species susceptible to ivermectin toxicity?
- dogs
- small birds
Why are Collies more susceptible to ivermectin toxicity?
ABCB1/MDR1 mutation
Ivermectin is 95% absorbable via what route?
Orally
In what species is oral absorption of ivermectin lower?
Ruminants
T/F: Dogs may have lower bioavailability than cats.
False - Cats may have lower bioavailability than dogs.
Does ivermectin typically cross the BBB?
No
How is ivermectin excreted?
Mainly unchanged in feces.
What is the elimination half-life of ivermectin in dogs?
2 days
Deletion/mutation of the ABCB1/MDR1 gene can result in how much of an increase in concentration of certain drugs in the CNS?
50x
What as been seen with co-administation of off-label (high dose) ivermectin and comfortis (Spinosad)?
Neurotoxicity
What is the main type of clinical sign seen with ivermecti toxicity?
CNS depression
Are there any specific pathologic lesions seen with ivermectin toxicity?
No
Do tissue levels of ivermectin correlate well to brain levels?
No
Is there any specific antidote for ivermectin?
No
Caution needs to be used with what types of drugs with ivermectin toxicity?
GABA agonists (diazepam, barbiturates, propofol)
What does prognosis of ivermectin toxicity depend on?
Exposure & ability to pay for care
T/F: Generally there are no long-term sequelae from ivermectin toxicity if the animal survives.
True
