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Flashcards in Anti-Trematode Agents Deck (32):
1

Most nematodes reside in the...

GI of the animal
*Nematodes (Roundworm)
*They can also reside in the heart and lungs.

2

Nematodes are also called

Roundworms

3

What are examples of Nematodes?

Roundworms, Pinworms, Stongyles, Trichostrongyles, Hookworms, Whipworms and Threadworms.

4

** This species of nematodes will look like _________ in the stomach..

In cattle (ruminants) looks like moracin leather.

5

This nematode species resides in the heart of dogs, wolves, cats and sea lions. Its intermediate host is the mosquito.

Dirofilaria immitis.

6

What is the general nematode life cycle?

-Ingestion/infection of dominant host with larvae/eggs > Migration (optional) and maturation in the D-host (associated with pathology) > elimination of egg/larvae by the D-host.

Elimination of egg/larvae by the D-host ? Ingestion/infection by Intermediate host (optional, associated with pathology , development of the parasite may occur) > elimination/consumption or vectoring leads to ingestion/infection of the dominant host with larvae/eggs.

*In the definitive host, nematodes can go to reproductive maturity*

7

Nematodes (Roundworms, Pinworms, Stongyles, Trichostrongyles, Hookworms, Whipworms and Threadworms) anatomy

Very advanced organ system.
Uses a stylet to attach to the host.

8

What drug treats flukes and roundworms?

Benzimidazoles.
(Albendazole, Fenbendazole, and thibendazole)

9

What is the mechanism of action of Benzimidazoles?
(Albendazole, Fenbendazole, and thibendazole)

1) Inhibits microtubule polymerization by binding to B-tubulin in ALL WORM STAGES. Binding is reversible, dissociates from parasitic tubulin more slowly than from host tubulin.
2) Toxicity to parasites is due to GI secretory defects and reduced glucose uptake by the worm GI tract.
3) Worms DIE prior to elimination.
*Microtubules provide the cell structure, prevents the worm from being able to get nutrients

10

Benzimidazoles _______ worms prior to elimination.

Worms DIE prior to elimination.

11

Benzimidazoles
(Albendazole, Fenbendazole, and thibendazole)
Absorption

Water insoluble compounds (formulated as pastes, suspensions and pellets, administer PO FDA approved)
Efficacy is increased by longer GI residency times; increased time in the GI leads to increased absorption. Absorbed drug is toxic to the worms. Not toxic in the GI tract lumen.

12

This drug is a water insoluble compounds formulated as pastes, suspensions and pellets, administer PO FDA approved.

Benzimidazoles
(Albendazole, Fenbendazole, and thibendazole)

13

Benzimidazoles
(Albendazole, Fenbendazole, and thibendazole)
Absorption in ruminants

Differences in the GI physiology dictate differences in the dosing frequencies.
Rumen is a reservoir- mixing and long residency solubilizes the drug. Acid pH of the abomasum solubilizes the drug.
Dosing: one dose followed by possible retreatment 4-6 weeks later.

14

Benzimidazoles
(Albendazole, Fenbendazole, and thibendazole)
Absorption in monogastrics

Differences in the GI physiology dictate differences in the dosing frequencies.
These drugs can include pigs but NOT horses.
Absorption is decreased due to rapid GI transit times.
Acid pH of the stomach solubilizes the drug.
Dosing: q24 hours for 3 days minimum (many vary depending on the nematode)

15

Benzimidazoles
(Albendazole, Fenbendazole, and thibendazole)
Distribution and Metabolism

Distribution (not-well described)
Metabolism: liver produces active metabolites*

16

Benzimidazoles
(Albendazole, Fenbendazole, and thibendazole)
Elimination

Fenbendazole in sheep, cattle and pigs.
45-55% eliminated unchanged in feces, <1% eliminated unchanged in the urine.

17

*****Benzimidazoles
(Albendazole, Fenbendazole, and thibendazole)
Adverse effects:

Hypersensitivity reaction to antigens from dying worms!

18

Benzimidazoles
-Fenbendazole
Morphology

Panacur and Pancur C
*Used in SMALL ANIMALS*

19

Benzimidazoles
-Fenbendazole
Labeled indications in dogs

Roundworms, hookworms, whipworms and tapeworms.
*Can use Febantal

20

Benzimidazoles
-Fenbendazole
Labeled indications in cats:

Roundworms, hookworms, strongloides, lung worms and Giardia.
*Can use Febantal

21

Benzimidazoles
-Fenbendazole
Labeled indications in cows:

Lung worms, stomach worms, intestinal worms and Haemonchus

22

*****Benzimidazoles
-Fenbendazole
Labeled indications in horses:

Stongyles (large and small), pinworms and ascarids.

23

Benzimidazoles
-Fenbendazole
Labeled indications in what species?

Dogs, cats, cows, horses, bears, large cats, rodents, ferrets, swine, sheep, goats, camelids, birds and reptiles.

24

******Benzimidazoles
-Fenbendazole
Adverse effects?

Hypersensitivity reaction to antigens from dying worms AND specifically pancytopenia.

25

This drug is a PRODRUG that is metabolized to Fenbendazole following absorption.

Febantel (prodrug)
*Also called Drontal

26

What is Febantel?

This drug is a PRODRUG that is metabolized to Fenbendazole following absorption.
Indications for use in DOGS and CATS.
*Also called Drontal

27

Benzimidazoles
Albendazole
Labeled indications in cats and dogs:

Cats and dogs: Giardia (not ideal in cats)

28

Benzimidazoles
Albendazole
Labeled indications in cows

Liver flukes, stomach worms, intestinal worms and lung worms.

29

*******Benzimidazoles
Albendazole
Labeled indications in what species?

Dogs, cats (not ideal), cows...

30

********Benzimidazoles
Albendazole
Adverse effects:

Hypersensitivity reaction to antigens from dying worms
PLUS
Aplastic anemia (implied, not proven) in dogs, cats and humans.
Potentially teratogenic, so consider Fenbendazole in pregnant animals.

31

*******What drug is potentially teratogenic, so consider Fenbendazole in pregnant animals.

Albendazole

32

*****Benzimidazoles
Fenbendazole can be used in...

HORSES