pharmacology 5 Flashcards
(21 cards)
parasiticide
drug that kills parasites
anthelmintic
drug that kills worm (helminths)
pesticide
drug usually used for external parasite/arthropods (extoparasiticide)
insecticide
kills insect
acaricide
kills ticks and mites
big three
benzimidazoles (BZD)
pro-benzimidazoles
nicotinic agonist
macrocyclic lactones (ML)
benzimidazoles and pro-benzimidazoles
generic names end in “azole”
widely used in vet med
fenbendazole
albendazole
febantel
oxibendazole and oxfendazole
benzimidazole mode of action
blocks assembly
bind to parasite beta tubulin
prevents microtubule assembly
interferes with cell internal structure and metabolism
causes slow parasite death
benzimidazole-spectrum of action
nematodes primarily
adulticidal, larvicidal, and ovicidal activity
no effect against hypobiotic
trematodes and cestodes
ruminants
adulticidal
(essentially in ruminant flukes and tapeworms)
admin and saftey-benzimidazole
administration-oral only not very water soluble
saftey-very safe
exceptions:do not give albendazole to early pregnancy ruminants
do not give febantel to pregnant dogs
benzimidazole-species
dogs-febantel, fenbendazole (albendazole not approved)
horses-fenbendazole
ruminants-albendazole and fenbendazole
pigs and poultry-fenbendazole
nicotinic agoinsts
imidazothiazoles and levamisole
tetrahydropyrimidines and pyrantel morantel
nicotinic mode of action
they act selectively as agonists at nicotinic receptors on nematodes muscle cells: depolarizing neuromuscular-blocking drug
contraction and rapid spastic paralysis of worms
nicotinic-spectrum of action
GIN adults
lung worms adults and larval stage
pyrantel-dogs <2 weeks
pyrantel-double dose in horse for tape worms
pyrantel and morantel not absorbed from the gut
administration and safety of nicotinic
administration orally
safety-margin of levamisole is lower than for other modern anthelmintics
signs of toxicity related to the mode of action: it works in the host cell as well: salivation, tremors, ataxia, urination and defecation
species of nicotinic agonists
horses, ruminants-mostly small, dogs and cats
macrocyclic lactones
milbemycins-moxidectin, milbemycin oxyme
avermectins-selamectin, ivermectin and eprinomectin
macrocyclic lactones-mode of action
bind to glutamate gated chloride channels leading to hyperpolarization of nerves and muscles
multiple effects in muscles: paralysis of muscles, affects parasite reproduction
some products have persistent activity, affected by formulation and administration route
macrocyclic lactones-spectrum of action
nematodes:adults, mucosal larvae and hypobiotic larvae
arthrodos: blood sucking and tissue dwelling, varies depending on product and species
route of administration and safety for macrocyclic lactones
admin: oral, injection, topical and absorbed through skin
safety: general wide safety margin, mammalian toxicity probably related to GABA synapse
macrolides generally dont reach susceptible target in vertebrates CNS because of the BBB
todxicity related to CNS depression
