Antiparasitics Flashcards
what is the mechanism of action of pyrethrins/pyrethroids?
neurotoxins
what does it mean that pyrethrins/pyrethroids are broad spectrum?
effective against insects and arachnoids
who should you not use pyrethrins/pyrethroids in?
puppies
kittens
debilitated animals
what are the signs of pyrethrin/pyrethroid toxicity in cats?
tremors
seizures
ataxia
death
what is the mechanism of action of organophosphates and carbamates?
inhibit acetylcholinesterase
what is the spectrum of organophosphates and carbamates?
broad: insects and arachnids
what signs are seen with overdose of organophosphates and carbamates?
SLUD signs +/- nicotinic effects: twitching, weakness, paralysis
what is the antidote of organophosphate or carbamate overdose?
2-PAM for organophosphates only
atropine for all
what is toxicity of formamidine (amitraz) due to?
alpha2-adrenergic agonism
who is formamidines (amitraz) not recommended in?
cats
what are neonicotinoids effective against?
adult fleas
what are some common neonicotinoids?
imidacloprid
spinosad
nitenpyram
which neonicotinoid is a P-glycoprotein inhibitor?
spinosad
who are neonicotinoids used in?
cats and dogs
what are the main indications for fipronil?
kill adult fleas: 24hours
kill ticks: 48hours
how is fipronil given?
topically to dogs and cats
what is one insect growth regulator?
lufenuron: chitin synthesis inhibitor
how do isoxazolines work?
neurotoxins: GABA antagonists
what do isoxazolines work against?
fleas and ticks
extralabel: Demodex, Sarcoptes, Otodectes
what isoxazolines are approved for cats?
topical fluralaner
what do benzimidazoles work against?
nematodes
cestodes
some trematodes
broad spectrum
protozoa- less common use (Giardia)
what are some benzimidazoles?
febantel (pro-drug)
fenbendazole
how does pyrantel work?
neurotoxin: cholinergic agonist
what is pyrantel effective against?
roundworms
hookworms
not whipworms or tapeworms
how safe is pyrantel?
very safe
what drug is used to deworm puppies and kittens?
pyrantel
start at 2 weeks of age, repeat every 2 weeks until 8 weeks old
why should you be careful of using pyrantel in horses? what other product can we use instead?
heavy ascarid burden: rapid kill can cause obstruction
fenbendazole is safer
what do isoquinolones work against?
cestodes and trematodes
what is a common isoquinolone?
praziquantel
deworm horses annually for Anoplocephala with ________________ or ________________ (double dose for tapeworms)
praziquantel
pyrantel
what is clorsulon: benzene sulfonamide used for?
liver flukes in cattle
what are macrocyclic lactones such as ivermectin and moxidectin used for?
nematodes
fleas
ticks
flies
grubs
mites
what things do macrocyclic lactones not work against?
flukes
tapeworms
biting lice
what are some macrocyclic lactones?
ivermectin
moxidectin
what are the two groups of macrocyclic lactones?
avermectins
milbemycins
do avermectins or mibemycins get whipworms?
milbemycins do get whipworms
how do macrocyclic lactones work?
neurotoxins
which collies have higher chances of being MDR1 mutants?
australian shepherds
mini australian shepherds
collies
longhaired whippets
ivermectin cannot penetrate mammalian CNS except in dogs with ______________________________ gene mutation
ABCB1 (previously known as MDR-1)
what are the CNS signs of ivermectin toxicity?
depression
ataxia
stupor
progressing to coma
death
can you use spinosad with ivermectin?
no
P-glycoprotein inhibitor
what is the safety margin like of moxidectin for large animals?
narrower than other macrocyclic lactones
what may overdosage of moxidectin in large animals result in?
serious adverse reactions (fatalities) in foals and miniature horses
never use in miniature horses
what is the recommended heartworm disease treatment for dogs?
doxycycline (Wolbachia treatment) and a macrocyclic lactone prior to the three-dose regimen of melarsomine
what is Haemonchus contortus?
problem in small ruminants: HOT complex
anemia and edema
what is refugia?
the portion of parasites that remain unexposed to a dewormer
what is emodepside?
octadesipeptide and new anthelminthic class effective against most GI nematodes
recommendation is to save for when parasitism is resistant to triple therapy with conventional agents
what products should you be careful of using with cats?
pyrethroids
permethrins
formamidines not recommended for cats
how toxic are insect growth regulators?
loe: mammals do not have chitin/insect hormones
what is extra-label use of isoxazolines for?
demodex
sarcoptes
otodectes
who are isoxazolines approved for?
dogs
only topical fluralaner approved in cats
does pyrantel work against whipworms or tapeworms?
no
what is the dosing regimen for deworming puppies and kittens?
start at 2 weeks of age
repeat every two weeks until 8 weeks
do avermectins get whipworms?
no
can you use moxidectin for large animals in miniature horses?
no
