34. drug use in ruminants Flashcards
3 major dug classes used for ruminants
Benzimidazoles (BZDs)
Imidazothiazoles/
Tetrahydropyrimidines
– Membrane depolarizers
Macrolide Endectocides
– Avermectin / Milbemycins (AM)
white wormers are
benzimidazoles (BZ)
broad spectrum
adulticidial
short acting
safest!
what is the safest type of drugs for ruminants
Benzimidazoles- white wormers
toxic dose is 10 to 100 X therapeutic dose for most BZ drugs
most commonly used Benzimidazole (BZ)
fenbendazole (FBZ)
some benzimidazoles
fenbendazole
oxfendazole
albendazole
what is the strongest benzimidazole?
albendazole
can be used against liver flukes
how does benzimidazole work
binds to B tubulin cap of parasite
prevents these from going on and doing tasks like glucose metabolism, cell structure- everyday function
what will increase efficacy of Benzimidazole
oral drug
if you hold food for 24 hours, will slow down gut and increase contact time with drug
repeat dose
which BZD are teratogenic in mice and should not be given during pregnancy
Albendazole
what type of animals are resistant to BZDs
small ruminants and zoo animals
not normally a problem in cattle parasites
what are two families of membrane depolarizers
imidazothiazoles and tetrahydropyrimidines
how do membrane depolarizers work
Cholinergic agonists
Depolarizing neuromuscular blocking agents acting at acetylcholine receptors
Cause spastic paralysis of worms
Imidazothiazoles
– Levamisole, butamisole Tetrahydropyrimidines
– Pyrantel, morantel
Imidazothiazoles
— and butamisole Tetrahydropyrimidines
– Pyrantel and —
Levamisole
morantel
membrane depolarizers
— is the treatment of choice for goats with Haemonchus infection
Levamisole
want to save this drug for worst case senerios- dont want to cause resistance
membrane depolarizer: Imidazothiazoles
– Levamisole, butamisole
Levamisole is — spectrum and can be used when during pregnancy
broad spectrum
safe for pregnant animals except for last 3 weeks of goat gestation
membrane depolarizer: Imidazothiazoles
– Levamisole, butamisole
Levamisole can be given
oral, injectable or topical
membrane depolarizer: Imidazothiazoles
– Levamisole, butamisole
Levamisole has a high or low therapeutic dose
low
can not change dose- toxic at 3-5 x will cause ataxia and muzzle foaming
Levamisole is not a good drug for
L4 (dorment) O. ostertagi
pyrantel of ruminants
morantel
— is an oral med that is mixed into feed, broad spectrum and can be used in lactating animals
Morantel
membrane depolarizer:
Tetrahydropyrimidines
– Pyrantel, morantel
— is the most perfect/ Effective drug against most nematode and
arthropod parasites
avermectin/milbemycins
endectocides
naturally occuring from surface dwelling bacteria Streptomyces spp.
how does Avermectin work
acts at glutamate gates and GABA gated chloride channels
— are dose limiting parasites in cattle
cooperia
— works 99% of the time on both adult and larval and arrested larval strongylid nematodes
Avermectin/milbemycin (AM)
