Test 3: 41 anthelminitics part 1 Flashcards
what two systems do anti parasite drugs effect
neurotransmission
cellular integrity
Macrocyclic lactones have Broad-spectrum activity against most —
nematodes (including immature forms - hypobiotic larvae) and arthropods
not effective against adult heartworm, but works for immature worms
macrocyclic lactones are ineffective against —
cestodes and trematodes and adult heartworm (D. immitis)
broad spectrum anti parasite for nematodes and arthropods
dosing of macrocyclic lactones
monthly - persistent efficacy
well absorbed into GI, lungs and skin regardless of route of administration
effective against nematodes, arthropods and immature heartworm
not effective against cestodes and trematodes and adult heartworm
how do macrocyclic lactones work
Bind with high affinity to a glutamate-gated chloride channel
MLs bind to glutamate receptors that trigger chloride influx
Prevents initiation or propagation of normal action potentials
The net effect is paralysis and death of the target parasite!!
side effects of macrocyclic lactones
toxic: collies with MDR1 (ABCB1) gene: vomting, lethargy, tachycardia
excreted as active drug- may have environmental effect- toxic to aquatic animals
what are some macrocyclic lactones
ivermectin (heart worm)
moxidectin (proheart)
milbemyxin oxime (interceptor)
Doramectin
selamectin (revolution)
eprinomectin
ivermectin
macrocyclic lactone
Safe in Collies and in all breeds, even dogs with mutant MDR1
used in Cattle, sheep, swine, horses, bison, reindeer, dogs, and cats
withdrawal 35 d dairy, 14 d meat
heartgard
moxidectin
macrocyclic lactone
Cattle, sheep, horses, dogs, cats, and ferrets(heartworm)
Moxidectin pour-on is approved for use in beef and dairy cattle
100% efficacy in preventing Ancylostoma caninum in dams and pups when given on pregnancy day 55
Wider margin of safety than IVM for Collies (30X)
proheart
milbemyxin oxime
- Dogs and cats
- Considered safe for pregnant and nursing animals
- It is nontoxic to rough-coated Collies at up to 20X the recommended dose
macrocylic lactone- interceptor
doramectin
macrocyclic lactone
Cattle and swine
It is NOT RECOMMENDED for use in dogs and cats
Withdrawal interval of 35d (milk) and 14d (meat) (same as ivermectin)
selamectin
Dogs and cat
safe in MDR1 mutant
dogs when given at 40 mg/kg topically
oral doses of 15 mg/kg, MDR1 mutant dogs have only mild signs of neurologic toxicity
revolution
eprinomectin
Approved in a topical and injectable formulation for use in cattle only
* Combination product of EPM and praziquantel is approved for cats
* Extralabel: sheep, donkeys, rabbits
two types of tetrahydropyrimidine anti-parasite
pyrantel (dog, horse, swine)
morantel tartrate (ruminants)
Tetrahydropyrimidine anti parasites are broad spectrum for —
adult GI nematodes
except for whipworms (trichuris)
pyrantel
morantel tartrate
how do tetrahydropyrimidines work
- Act as nicotinic agonists that disturb the neuromuscular junction
- Nicotinic acetylcholine receptors are essential for neurofunction
- Depolarization of the muscle membrane, contraction and subsequent paralysis
antiparasite: pyrantel, morantel tartrate
pyrantel
Horses, swine, and dogs
It is NOT APPROVED for use in ruminants but has been recommended/considered effective for GI nematodes
Resistance to pyrantel is common in equine parasites
simparica trio
heartgard
— can prevent the apperance of “ milk spots” in the liver from the migration of Ascaris suum
pyrantel tartrate
horse and swine
white powder, soluble in water
pyrantel tartrate vs pyrantel pamoate
pyrantel tartrate: white powder, soluble in water, horses and swine, prevent milk spots from Ascaris suum
Pyrantel pamoate: yellow, insoluble in water, horses and dogs, safe in pups and pregnant animals
benzimidazoles are effective against
nematodes, most cestodes, and some trematodes in horses and ruminants
Can not treat trematodes in dogs and cats
poorly soluble in water- give before food, slow acting compound
how do benzimidazole work
Disrupt parasite cell division
* Bind to parasite β-tubulin molecules and inhibit formation of microtubules
* Microtubules provide structure and shape to eukaryotic cells
* Higher affinity for nematode tubulin than mammal tubulin
Blocks mitochondrial function
* Can inhibit fumarate reductase
* Deprive the parasite of energy and result in death
treat nematodes, most cestodes and some trematodes in horses and ruminants
may need to redose at BID, poorly absorded and slow acting
give on empty stomach, more effective at lower pH
side effects of benximidazole
teratogenicity- congenital malformation, embryo lethal effects
Withholding period after anthelmintic treatment for food-producing animals
* 8-14 days before slaughtering for meat * 3-5 days before milking for human consumption
albendazole, febendazole
albendazole
benzimidazole antiparasite
Cattle, sheep and goats
* GI nematodes
* Lung nematodes, including larval forms
* Cestodes
* Lung and liver trematodes
NOT APPROVED for use in dogs and cats
febendazole
Ruminants, horses, swine, dogs, and zoo animals
* Considered safe to use in pregnancy
* Have been used off label (US) to treat giardiasis
treat Gi nematodes, lung nematodes, cestodes
does not treat trematodes like albendazole
panacur, safeguard
OXIBENDAZOLE
benzimidazole antiparasite
horses
Apparently effective against small strongyles that are resistant to BZs
isoquinolones are effective for
cestodes and tramatodes of genus schistomsoma
cattle and people
should not be used in puppies or kittens younger than 7 weeks
what are some isoquinolones
praziquantel and epsirprantel
safe and effective against cestode and trematodes of schistosoma
how does isoquinolone work
exact mechanism unknown
Attack the parasite neuromuscular junction and the tegument
cause contraction and paralysis of the parasite
Vacuolization and destruction of the protective tegument
attack cestodes and Schistosoma trematodes
praziquantel
should not be used in puppies and kittens younger than 7 weeks
of age
kills adult and larval cestodes and Schistosoma sp. trematodes
FDA-approved for dogs and cats
- Available for horses in combination with MLs only
isoquinolones: praziquantel, epsiprantel
epsiprantel
Cestodes
* Dogs and cats - Cestex (Zoetis)
Arsenicals treat —
adult heartworms ( Dirofilaria immitis)
NOT SAFE for cats - toxicity problems
Dogs with moderate risk of thromboembolism: AHS treatment protocol
melasormine
how to treat heartworm in dogs and cats
cats no treatment
dogs: arsenical antiparasities such as melasormine
kills adult heartworm- D. immitis
clorsulon
Very effective in cattle against all stages of Fasciola hepatica (liver fluke/trematodes)
NOT EFFECTIVE against Paramphistomum sp. (rumen fluke)
Limitation: withdrawal has not been established - avoid lactating cattle
