Lecture 32: Anti-Nematode Agents

Question 1

What is the life cycle for nematodes

Answer 1

1. Ingestion of larvae/eggs
2. Migration and maturation in host
3. Elimination of egg/ larvae
4. Ingestion eggs by host
   4a. Ingestion/ infection by intermediate host
   5a. Consumption or vectoring
   6a. Ingestion by definitive host

Question 2

What is fenbendazole approved for in dogs

Answer 2

Roundworms, hookworms, whipworms

Question 3

What is fenbendazole approved for in cats

Answer 3

Roundworms, hookworms, strongyloides, lungworms and Giardia

Question 4

What is fenbendazole approved for in cows

Answer 4

Lungworms, stomach worms, intestinal worms

Question 5

What is fenbendazole used for in horses

Answer 5

Strongyles, pinworms, ascarids

Question 6

Febantel is a prodrug that is metabolized to ___following absorption

Answer 6

Fenbendazole

Question 7

What is febantel indicated for

Answer 7

Dogs: roundworms, hookworms, whipworms

Cats: roundworms, hookworms, strongyloids, lung worms, Giardia

Question 8

What is albendazole approved for cats and dogs

Answer 8

Giardia

Question 9

What is albendazole approved for in cows

Answer 9

Stomach worms, intestinal worms, lung worms

Question 10

What is levamisole indicated for in cattle (beef and non-lactating dairy), sheep’s and goats

Answer 10

1. Mature and larval lung worms
2. Mature stages of GI worms

Question 11

What is levamisole approved for in swine

Answer 11

Mature stages of GI worms

Question 12

Levamisole parent compound is broken down into what 2 compounds

Answer 12

1. I-tetramisole-levamisole: anti-nematodal effects, toxicity
2. D-tetramisole- no anti-nematodal effects, toxicity

Question 13

What is the Pd of levamisole

Answer 13

1. NM agonist- causes tetanic paralysis- worms unable to maintain attachment to host

Question 14

Levamisole paralyzes worms but still alive when excreted in feces so important that owner ___

Answer 14

Picks up feces otherwise reinfection

Question 15

Levamisole is best absorbed when given ___

Answer 15

SQ

Question 16

Levamisole is not to be used in what animals and why

Answer 16

Lactating dairy cattle- enters milk of cattle 1hr following SQ administration

Question 17

Levamisole is metabolized in ___

Answer 17

Liver

Question 18

How levamisole eliminated

Answer 18

60% in urine, 30% in feces

Question 19

Toxic signs of levamisole look like ___

Answer 19

SLUDGE
Salivation, lacrimation, urinary, defecation, GI upset, emesis

Question 20

What are some adverse effects of levamisole

Answer 20

1. Stimulates NM receptors in hist- muscle fasisculations
2. SLUDGE

Question 21

Toxicity of levamisole may be increased by concurrent treatment with ___, ___ or __

Answer 21

Pyrantel, morantel or AChE inhibitors

Question 22

What species is very intolerant of levamisole

Answer 22

Horses

Question 23

What is morantel indicated for

Answer 23

GI worms in cows sheep and goats

Question 24

What is pyrantel indicated for

Answer 24

GI worms

Question 25

Which has worse absoprtion: morantel or pyrantel

Answer 25

Morantel

Question 26

Pyrantel and morantel are only administered ___

Answer 26

PO

Question 27

Pyrantel and morantel are maintained in the GI tract of ruminants for up to ___days

Answer 27

98 days

Question 28

Pyrantel and morantel have better absoprtion when given with __ in small animals

Answer 28

Food

Question 29

Pyrantel and morantel are eliminated via

Answer 29

Urine

Question 30

Horses tend to tolerate ___salt better than palmate salt

Answer 30

Tartate salt

Question 31

What is piperazine indicated for in dogs and cats

Answer 31

Toxocara spp and Toxascaris leonina

Question 32

What is piperazine indicated for in horses

Answer 32

Cynthomes, ascarids, and pinworms

Question 33

What is piperazine indicated for in pigs

Answer 33

Ascarids and modular worms

Question 34

What is the PD of piperazine

Answer 34

GABA receptor agonist- hyperpolarizes cell—> flaccid paralysis

Question 35

You should not give piperazine with ___, ___ and ___ due to competition

Answer 35

pyrantel, morantel, and levamisole

Question 36

Piperazine is not effective against ___eggs

Answer 36

Nematode

Question 37

Piperazine is metabolized by the ___

Answer 37

Liver

Question 38

Piperazine is eliminated in the ___

Answer 38

Urine

Question 39

What are some adverse effects of piperazine in dogs and cats

Answer 39

Emesis, diarrhea, ataxia, muscle tremors, behavior alteration, head pressing

Question 40

What is emdoespide indicated for

Answer 40

Labeled for Toxocara cati and acylostoma tubaeforme in cats

Question 41

What is the PD of emodepside

Answer 41

Latrophilin receptor agonist in nerves—> induces release PF-1 like neuropeptide—> hyperpolarizes muscle cells in the nematode pharynx—> flaccid paralysis of muscles necessary for ingestion

Question 42

All mechanisms of resistance to nematode drugs involve altered ___ and are ___

Answer 42

Genetics, heritable

Question 43

What are the three examples of resistance seen in H. Contorts

Answer 43

1. Number of drug targets decreases- decreases NM receptors
2. Affinity of target for drug is decreased- altered B-tubulin structure
3. Elimination of drug increases- increased P-gp

Question 44

Decrease expression of NM receptors caused resistance in __ and __

Answer 44

Levamisole and pyrantel

Question 45

Altering B-tubular structure caused resistance to ___

Answer 45

Albendazole

Question 46

Increasing P-gp causes resistance to __ and ___

Answer 46

Albendazole and avermectins

Question 47

What are some recommendations for limiting resistance

Answer 47

1. Use drugs indicated for species
2. Given full treatment course (2)
3. Rotate between indicated drugs
4. Treat at defined thresholds
5. Monitor parasite levels in patient populations/ herds