Test 3: 41 anthelminitics part 1

Question 1

what two systems do anti parasite drugs effect

Answer 1

neurotransmission

cellular integrity

Question 2

Macrocyclic lactones have Broad-spectrum activity against most —

Answer 2

nematodes (including immature forms - hypobiotic larvae) and arthropods

not effective against adult heartworm, but works for immature worms

Question 3

macrocyclic lactones are ineffective against —

Answer 3

cestodes and trematodes and adult heartworm (D. immitis)

broad spectrum anti parasite for nematodes and arthropods

Question 4

dosing of macrocyclic lactones

Answer 4

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

Question 5

how do macrocyclic lactones work

Answer 5

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!!

Question 6

side effects of macrocyclic lactones

Answer 6

toxic: collies with MDR1 (ABCB1) gene: vomting, lethargy, tachycardia

excreted as active drug- may have environmental effect- toxic to aquatic animals

Question 7

what are some macrocyclic lactones

Answer 7

ivermectin (heart worm)
moxidectin (proheart)
milbemyxin oxime (interceptor)
Doramectin
selamectin (revolution)
eprinomectin

Question 8

ivermectin

Answer 8

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

Question 9

moxidectin

Answer 9

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

Question 10

milbemyxin oxime

Answer 10

• 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

Question 11

doramectin

Answer 11

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)

Question 12

selamectin

Answer 12

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

Question 13

eprinomectin

Answer 13

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

Question 14

two types of tetrahydropyrimidine anti-parasite

Answer 14

pyrantel (dog, horse, swine)

morantel tartrate (ruminants)

Question 15

Tetrahydropyrimidine anti parasites are broad spectrum for —

Answer 15

adult GI nematodes

except for whipworms (trichuris)

pyrantel
morantel tartrate

Question 16

how do tetrahydropyrimidines work

Answer 16

• 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

Question 17

pyrantel

Answer 17

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

Question 18

— can prevent the apperance of “ milk spots” in the liver from the migration of Ascaris suum

Answer 18

pyrantel tartrate

horse and swine
white powder, soluble in water

Question 19

pyrantel tartrate vs pyrantel pamoate

Answer 19

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

Question 20

benzimidazoles are effective against

Answer 20

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

Question 21

how do benzimidazole work

Answer 21

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

Question 22

side effects of benximidazole

Answer 22

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

Question 23

albendazole

Answer 23

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

Question 24

febendazole

Answer 24

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

Question 25

OXIBENDAZOLE

Answer 25

benzimidazole antiparasite

horses

Apparently effective against small strongyles that are resistant to BZs

Question 26

isoquinolones are effective for

Answer 26

cestodes and tramatodes of genus schistomsoma

cattle and people

should not be used in puppies or kittens younger than 7 weeks

Question 27

what are some isoquinolones

Answer 27

praziquantel and epsirprantel

safe and effective against cestode and trematodes of schistosoma

Question 28

how does isoquinolone work

Answer 28

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

Question 29

praziquantel

Answer 29

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

Question 30

epsiprantel

Answer 30

Cestodes
* Dogs and cats - Cestex (Zoetis)

Question 31

Arsenicals treat —

Answer 31

adult heartworms ( Dirofilaria immitis)

NOT SAFE for cats - toxicity problems
Dogs with moderate risk of thromboembolism: AHS treatment protocol

melasormine

Question 32

how to treat heartworm in dogs and cats

Answer 32

cats no treatment

dogs: arsenical antiparasities such as melasormine

kills adult heartworm- D. immitis

Question 33

clorsulon

Answer 33

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