Lecture 31: Anti-Cestode and Trematode Agents

Question 1

What is the lifecycle for Tapeworms

Answer 1

1. Humans infected and eggs or gravid proglottids excreted in feces
2. Cattle and pigs ingest vegetation contaminated with feces
3. Penetrate intestinal wall and circulate to muscle
4. Oncospheres develop and encyst into muscle
5. Humans infected by ingesting raw or undercooked infected meat

Question 2

What is Praziquantel indicated for

Answer 2

1. All tapeworms in dogs, cats and horses
2. Only drug effective against E. Granulosus

Question 3

Praziquantel is not approved for use in ___

Answer 3

Food animals

Question 4

What is the only drug approved for E. Granulosus

Answer 4

Praziquantel

Question 5

What is the PD for praziquantel

Answer 5

Altered intracellular calcium homeostasis leading to disruption of cellular metabolism leading to titanic paralysis and tegumentary breakdown—> host immune response—> dead tapeworms

Question 6

Praziquantel has poor oral bioavailability due to extensive ___but metabolites are ___

Answer 6

First pass metabolism by the liver, active

Question 7

T or F: praziquantel is distributed to CNS

Answer 7

True

Question 8

How is praziquantel excreted

Answer 8

Urine

Question 9

What is epsiprantel used for in dogs

Answer 9

Dipylidium canines and Tania pisiformis

Question 10

What is epsiprantel used for in cats

Answer 10

Dipylidium caninum and Tania taneiaeformis

Question 11

Epsiprantel is not approved for use in ___

Answer 11

Food animals

Question 12

What is the PD for epsiprantel

Answer 12

Altered intracellular calcium homeostasis leading to disruption of cellular metabolism leading to titanic paralysis and tegumentary breakdown—> host immune response—> dead tapeworms

Question 13

Epsiprantel has very poor absorption from ___

Answer 13

GI tract

Question 14

Epsiprantel is eliminated in the ___

Answer 14

Feces

Question 15

Since epsiprantel is not absorbed into the body its effects on the cestode are due to ___not ____

Answer 15

Direct uptake of the drug by parasite not by transport of the drug by the host to the parasite

Question 16

What is the life cycle for F. Hepatica (flukes)

Answer 16

1. Umembryonated egg capsule excreted in feces
2. Miracadium infects snail
3. Gymnocephalus cercaria excreted by snail
4. Metacecaria on vegetation
5. Cows/sheep eat vegetation

Question 17

What is the pathway of immature flukes in host tissue

Answer 17

1. Penetrate GI and traverse peritoneum to liver in 4 days
2. Migrate and feed on liver
3. At 8 weeks penetrate bile ducts

Question 18

Mature flukes feed on ___ and cause ___

Answer 18

Blood, cause biliary hyperplasia and progressive occlusion

Question 19

What is Clorsulon indicated for

Answer 19

1. Fasciola spp in cattle and sheep

Question 20

Clorsulon is not effective against flukes before ___post infection

Answer 20

8 weeks

Question 21

What does ivomec Plus contain and cover

Answer 21

Contains both Clorsulon and ivermectin, so covers flukes and nematodes

Question 22

What is the PD for Clorsulon

Answer 22

Stops glycolysis by inhibiting phosphoglyceromutase and phosphoglycerate kinase

Question 23

What is the route of administration of Clorsulon to flukes

Answer 23

Ingestion of blood containing the drug

Question 24

T or F: Clorsulon is unmetabolized

Answer 24

True

Question 25

How is Clorsulon eliminated

Answer 25

Urine

Question 26

What broad class is albendazole and fenbendazole affective against

Answer 26

Tapeworms

Question 27

what drug is used to tx Moniezia in non-lactating cattle

Answer 27

Albendazole

Question 28

Fenbendazole is effective against ___ in dogs and cats

Answer 28

T. Pisiformis in dogs and cats

Question 29

Albendazole is effective against ___ in cattle

Answer 29

F. Hepatica

Question 30

Albendazole is effective against F. Hepatica ___weeks post infection

Answer 30

12 weeks

Question 31

Fenbendazole is 95% effective against ___in sheep

Answer 31

F. Gigantica

Question 32

___approved for roundworms and giardia in dogs, cats, horses and cattle

Answer 32

Benzimidazoles

Question 33

What is the PD of benzimidazoles

Answer 33

Inhibit microtubule polymerization by binding to B-tubulin in all parasite stages

Question 34

Benzimidazoles toxicity to parasites is due to ___ and ___

Answer 34

GI secretory defects and reduced glucose uptake by GI tract

Question 35

Efficacy of Benzimidazoles is increased by longer ___ leading to increased ___

Answer 35

GI residency times, increased absoprtion

Question 36

Differences in ___dictate differences in dosing frequencies for Benzimidazoles

Answer 36

GI physiology

Question 37

What is the dosing of Benzimidazoles in ruminants and why

Answer 37

One dose followed by possible retreatment 4-6 weeks later Rumen is reservoir and stays there for while

Question 38

Absoprtion of benzimidazoles in monogastrics is ___due to rapid ___

Answer 38

Decreased due to rapid GI transit times

Question 39

What is the dosing of benzimidazoles in monogastrics and why

Answer 39

Q24 for 3 days minimum due to fast GI transit times

Question 40

How are Benzimidazoles eliminated

Answer 40

Unchanged in feces

Question 41

What is an adverse effect caused by all benzimidazoles

Answer 41

Hypersensitivity reaction to antigens from dying worms

Question 42

What is an adverse effect of fenbendazole

Answer 42

Pancytopenia

Question 43

What are some adverse effects of albendazole

Answer 43

Aplastic anemia

Question 44

Albendazole is contraindicated in what patients

Answer 44

Pregnant, potentially teratogenic