Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DWT exam 2 > antihelminthics > Flashcards

antihelminthics Flashcards

1
Q

What is an anthelminthic?

A

kills worms (helminths)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Parasiticide

A

Drug that kills parasites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Pesticide

A

Drug usually used for external parasites/arthropods (Ectoparasiticide)
includes insecticides and acaricide (ticks/mites)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Insecticide

A

kills insects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Acaricide

A

kills ticks/mites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3 major gorups of anthelminthics

A
  1. Benzimidazoles (BZD) and pro-benzimidazoles
  2. Nicotinic agonists
  3. Macrocyclic Lactones (ML)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Benzimidazoles and pro-benzimidazoles

A

Generic names in this group usually end in -azole

Fenbendazole
Albendazole
Febantel
Others: Oxibendazole, oxfendazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Benzimidazoles and pro-benzimidazoles mode of action

A

Prevents microtubule assembly
Interferes with cell internal structure and metabolism
Causes slow parasite death

Need to stay around for awhile to work
* Rumen and cecum act as reservoir for absorption in ruminants and horses, respectively (only 1 dose needed)
* Small animals usually need several doses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Benzimidazoles and pro-benzimidazoles spectrum of action

A

Nematodes - primarily
* Adulticidal, larvicidal, and ovicidal activity

Trematodes and Cestodes - adulticidal ONLY IN RUMINANTS
(essentially in ruminant flukes and tapeworms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Benzimidazoles and pro-benzimidazoles administration

A

Oral only, not very water soluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Benzimidazoles and pro-benzimidazoles safety

A

Generally very safe
Exceptions: on the label, follow directions
* Albendazole: ruminants during early pregnancy (teratogenic)
* Febantel: dogs during pregnancy

Occasionally, toxicity with extra-label use in exotic species - check before use it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which Benzimidazoles and pro-benzimidazoles are used for which species?

A

Dogs - widely used
* Febantel, fenbendazole
* Albendazole not approved

Horses - widely used
* Fenbendazole

Ruminants - widely used
* Albendazole, fenbendazole

Pigs and poultry - widely used
* Fenbendazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

nicotinic agonists families

A

Two families:
* Imidazothiazoles (levamisole)
* tetrahydropyrimidines (pyrantel, morantel)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

nicotonic agonists mode of action

A

They act selectively as agonists at nicotinic receptors on nematode muscle cells: depolarizing neuromuscular-blocking drugs
Contraction, and rapid spastic paralysis of worms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

nicotinic agonists administration

A

primarily oral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

nicotinic agonists spectrum of action

A

only work against adults
Lung worms adults and larval stages
Pyrantel and morantel not absorbed from the gut
* only work against worms in the lumen (adults)
* can use in puppies under 2 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

nicotinic agonists safety

A

Safety margin of levamisole is lower than for other modern anthelmintics
Signs of toxicity related to the mode of action: it works in the host cells as well (block musc depolarization): salivation, tremors, ataxia, urination, defecation

18
Q

pyrantel against tapeworms in horses

A

use a double dose

19
Q

Macrocyclic Lactones

A

2 families: milbemycins and avermecins
products of soil fungus

20
Q

Macrocyclic Lactones mode of action

A

Bind to glutamate gated chloride channels leading to hyperpolarization of nerves and muscles
Multiple effects in muscles: paralysis of muscles, affects parasite reproduction
Some products have persistent activity, affected by formulation and administration route

21
Q

Macrocyclic Lactones Spectrum of action

A

Nematodes: adults, mucosal larvae, hypobiotic larvae (becuase it stays a long time, not that it actually kills them)
Arthropods: blood sucking and tissue dwelling. Varies depending on product and species

22
Q

Macrocyclic Lactones routes of administration

A

Oral
Injection
Topical, absorbed through skin

23
Q

Macrocyclic Lactones safety

A

In general, wide safety margin
Mammalian toxicity probably related to GABA synapses (neurotransmitter in CNS of vertebrates)
Macrolides generally don’t reach susceptible targets in vertebrate CNS because of the blood brain barrier
Toxicity related to CNS depression

24
Q

ivermectin in dogs

A

Macrocyclic Lactones
Approved dose OK for all dogs
Higher doses may cause problem in dogs, especially Collie type
* Do not use at higher doses in dogs Collie type breeding
* Sensitivity due to mutation affecting P-glycoprotein (part of BBB)
* Other breeds have mutation but at a very low frequency (70% in Collies, 5% in mixed breed dogs)

Other ML have higher safety margin in susceptible dogs

25
Q

Where are macrocyclic lactones used?

A

Where are they used? - Everywhere!
* Horses
* Cattle
* Small ruminants
* Dogs and cats
* Many exotic animals
* Humans
* Fish

26
Q

Isoquinolines

A

Praziquantel and epsiprantel
Used for tapeworms and some flukes in small animals and horses
No effect on nematodes
Only drugs approved for tapeworms in small animals
Mode of action: unknown. It seems to affect permeability of calcium ions in the muscular membrane: tetanic contraction of muscles
Safe and effective

26
Q

Isoquinolines

A

Praziquantel and epsiprantel
Used for tapeworms and some flukes in small animals and horses
No effect on nematodes
Only drugs approved for tapeworms in small animals
Mode of action: unknown. It seems to affect permeability of calcium ions in the muscular membrane: tetanic contraction of muscles
Safe and effective

27
Q

What does Praziquantel treat?

A

tapeworms small animals

28
Q

Arsenicals

A

Melarsomine
Used for heartworm treatment because nothing else works
Most effective against adults
Not effective against microfilariae or L3, early L4
Not for dogs in poor health (many adverse reactions and side effects)
Mode of action unknown

29
Q

what is Melarsomine used to treat?

A

heartworms
arsenical

30
Q

Emodepside

A

Cyclic octadepsipeptides
Currently marketed for cats in US
Stimulates specific neuromuscular receptor
Spectrum: only nematodes

profender

31
Q

Clorsulon

A

Benzenesulfonamides
For bovine liver fluke (Fasciola spp.)
Sold in combination with ivermectin
Inhibits fluke glycolytic enzymes

32
Q

Which of the following anthelminthics act on the neuromusc system?
ivermectin
febantel
albendazole
fenbendazole

A

ivermectin

33
Q

which can be used againt nematodes, cestodes, and trematodes in ruminants?
macrocylic lactones
benzimidazoles
nicotinic
isoquinolines

A

benzimidazoles

34
Q

Which can be used against cestodes in small animals?
ivermectin
fenbendazole
pyrantel
praziquatel

A

praziquatel

35
Q

T/F
If 2 drugs have the same mechanism of action anthelminthic resistance to one means there is resistance to the other

A

true

36
Q

What is resistace?

A

It used to work, now it doesn’t
Resistance is a heritable characteristic
Results from random mutation always going on in a population
* Assume little or no advantage in the absence of the drug (low frequency in population)

Drug use selects for resistant alleles and increases their frequency in the population
Resistance mechanisms vary

37
Q

What’s different about resistance in multicellular organisms?

A

SEX

37
Q

What’s different about resistance in multicellular organisms?

A

SEX

38
Q

contributing factors to anthelminthic resistance

A

Animals eat where they defecate
Kept in groups
Prevalent approach has been to deworm to prevent any possible problem from developing
Widespread use of pour-ons in cattle
The more often the drug is used, the faster the resistance is developed
worse in GRAZING animals

39
Q

Refugia

A

Pool of parasites not exposed to drug
These are parasites not exposed to the drug when you give it – not the resistant ones
Goal is to dilute resistant genes in the parasite population: to delay anthelmintic resistance

Increasing use of targeted selective treatment contributes to the increase of the refugia
Avoids exposing all parasites in animals to a drug treatment
Examples:
* Herd of horses: only deworm individuals with high egg counts
* Flock of sheep: only deworm anemic ones

DWT exam 2 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions