Brainscape's Knowledge GenomeTM

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


See full index

Anatomy yrtwo semone > Pharmacology > Flashcards

Pharmacology Flashcards

1
Q

Describe the mechanism of action for Benzimidazoles ?

A

Mechanism of action Benzimidazoles

  • affects parasite eneergy metabolism preventing nutrient uptake
  • Drug binds to nematode tubulin (higher affinity than in mammals)
  • inhibits polymerisation of beta subunits of tubulin
  • results in mitotic arrest (lethal in rapidly dividing cells)
  • or disrupted homeostasis
  • worm expulsion
  • A high concentraion may inhibit fumerate reductase a nessary enzyme for anerobic respiration.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Provide examples of Benzimidazoles and clinical application in horses ?

A

Benzimidazoles

Example

Albendazole, triclabendazole, fenbendazole, oxfendazole, oxibendazole, parbendazole and mebendazole

Horse = useful large strongles, small pinworm, ascarids, lung worm,

BZDs combined with other drugs eg piperazine for oxyuris.

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

Describe the clinical applications of Benzimidazoles in ruminants and pigs ?

A

Benzimidazoles in ruminants and pigs

  • adult and larvae of lung worms
  • GI nematodes
  • limited activity against whip worms

diposition in these species is affected by oesophageal groove, fasting/ starvation and diet type.

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

Identify five antinematodal drugs (4) ?

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

Febantel how does it work ?

A

Febantel undergoes heptaic metabolism to active fen and oxfendazole.

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

Describe the clinical application of Benzimidazoles in horses ?

A

Benzimidazoles in horses

  • usefule against adult large strongles
  • small pin worm
  • ascarids
  • lung worm

BZDS combined with other drugs , eg piperazine for immature oxyuris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the pharmacokinetics of binzimidazoles ?

A

Pharmacokinetics of binzimidazole ?

  • poor absorption from the GI tract and variable bioavailability
  • a full stomach or fatty meal is reccomened for fenbenzol in dogs
  • efficiancy is time dependant (dependant on duration of exposure and this class has minimal residual activity.)
  • toxicity is rare - ParBDZ and camBDZ are contraindicated in pregnant animals especially ewes. Withdrawl periods of two weeks for food animals.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Know the effectiveness of Benzimidazoles (table) in dogs and cats ?

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

Name a benzimidazole which that only has approval as a flukacide ?

A

Triclabendazole

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

Describe the mechanism of action of nicontenic anthelminitics and imidazothiazoles ?

A

Mechanism of action

These drugs selectively bind to and stimulate parasite nicotinic cholingeris (nAChR)

These are L or N type receptors that cause spastic paralysis when stimulated

Exposure to high doses over time may be associated with resistance

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

Provide examples of Nictinic anthelmintics and imidazothiazoles ?

A

This group of drugs includes

Tetrahydrppyrimidines = pyrantel and oxantel

Imidazothiazoles = levamisole

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

Describe the general pharmokinetics of Levamisole ?

A

Pharmakokinetics of Levamisole

  • Aministrated as a drench, bolus, pour on or SC injection.
  • rapidly absorbed
  • undergoes metabolism
  • excreted primarily by the kidneys
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the general pharmakokinetics of Pyrantel and Oxantel ?

A

Pharmakokinetics pyrantel and oxantel

  • Embonate salts have low solubility and low systemic availability esp. ruminants
  • this may contribute to increased efficacy for GIT nematodes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the clinical applications of Levamisole ?

A

Clinical application of Levamisole

Levamisole is generally less effective against immature and arrested forms

Ruminant

  • abomasal abomasal haemonchus and ostertagia
  • small intestine cooperia, trichostrongylus, bunostonum
  • large intestine oesophagastomum
  • lung worms (mature and immature) dictocaulus

Swine

  • ascaris, strongyloides, metastrongylus, stephanurus and oesphagostomum

Poultry

  • ascaridia, heterakis, capillaria and oxyspiruria

Dogs and cats

  • rarely used low therapeutic index
  • Toxocara, Toxoscaris
  • vomiting and anemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the clinical application of Pyrantel and Oxantel ?

A

Clinical application Pyrantel and Oxantel

Horses

  • GI parasites Parascaris, equorum, strongylus
  • not effective against strongles Edentates
  • ileo caecal tape worm, anoplocephala

Dog

  • Not effective against canine whipworm and tapeworm or heart worm

Anthelmentic spectrum in cats dogs and swin is very similar to Levamisole.

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

Compare Levamisole to pyrantel/oxantel ?

A
17
Q

What are tetrahydropyrimidines and Imidazothiazoles?

A

Tetrahydropyrimidines

  • Pyrantel
  • Oxantel
  • Morantel

Imidazothiazoles

  • Levamisole
18
Q

Provide a number of examples of Macrocyclic lactones ?

A

Macrocyclic lactones - antinematodal drugs

  • Avermectin
  • Ivermectin
  • Selamectin
  • Milbemycins
  • Moxidectin
  • Abamectin
19
Q

Describe the action and effect of Amino-acetonitrile derivatives ?

A

Amino-acetonitrile derivatives

  • Monepantel
  • Derquantel is a cholinergic receptor antagonist
  • Oral anthelmintic for sheep harmonchus, ostertagia, trichostrongylus, nematodirus and cooperia
20
Q

Describe the mechanism of action for Macrocyclic lactones ?

A

mode of Action , Macrocyclic lactones

  • Selectively activate release of gamma aminobutyric acid (GABA)
  • or activate glutamate gated channels causing the opening of GABA gated CL channels hyperpolarisation
  • impair of neural transmission (flaccid paralysis)
  • poor CNS penetration for mammals hence the selectivity
21
Q

Describe the clinical application of Macrocyclic lactones ?

A

Clinical application Macrocyclic lactones ?

Are active against endoparasites (nematodes), and ectoparasites (arthropods)

Avermectins = major GI and lung nematodes (haemonchus, ostertagia), ear mites and sarcoptic spp, otodectes spp, infective stage heart worm

Doramectin = injectable or pour on in ruminants

Abamectin drench in sheep, cattle and horses

Milbemycin’s oxime tablets in combination with praziquantel and /lufenuron

Nematodes and external parasites, Toxocara, trichuris, ancylostoma, dog pre-cardiac heart microfilariae

22
Q

Describe the pharmakokinetics of Macrocyclic lactones ?

A

Pharmakokinetics Macrocyclic lactones

slow deposition kinetics- sustained tissue concentrations - extended efficiacy

  • available as oral, injectable or pour on
  • absorption dependant elimination
  • exhibits strong absorption to particulate ingesta
  • fat and adipose are a good reservior
  • exhibit extensive distribution with reversable plasma - tissue exchangeand relatively low metabolic clearance
  • long half life
  • some such as moxidectin exhibit-hepatic recirculation and extensive biliary secretion
  • generally good substrates for P-glycoprotein
23
Q

Identify three drugs suitable for the treament of heart worm ?

A
24
Q

Which is the only clinical efficious agent against adult heart worm in dogs and is administered by intramuscular injections?

A

Malarsomine

efficient agent against adult heart worm by intramuscular injection.

25
Q

What could assentuate anthelmintic resistance ?

A

Anthelmintic resistance

Causes of anthelmentic resistance

  • incorrect diagnosis
  • unrealistic therapeutic objectives
  • inappropriate prescription
  • inappropriate dose regime/ drug interaction
  • re infection
  • inadequate inadequte integration of management statagies and chemotherapy
  • drug induced selection

Cause of drug resistance

26
Q

Treatment should only be apart of the management plan, what other factors can be changed ?

A

Management strategies for parasite burdens

  • good management
  • sanitation
  • quarantine and deworm new animals
  • not ovestocking
  • graze multiple species
  • zero grazing
  • alternative forages (tanins can be effective)
  • genetics
27
Q

What is a FECRT and how should it be carried out ?

A

FECRT = fecal egg count reduction test

  1. facel egg count prior to deworming
  2. facel egg count 10-14 days post deworming
  3. resistance =

<90-95% egg reduction is moderate

<60% egg reduction is severe

28
Q

If resistance is enivatable, what can be done to prevent it (6) ?

A
29
Q

What are refugia ?

A

Rufugia

The proportion of the population not underselection for drug treatment.

In refuge

  • worms in untreated animals
  • eggs and larvae on pasture

Provides a pool of sensitive genes by diluting the frequency of resistant genes.

30
Q

Discuss what is FAMACHA, and why is it useful ?

A

FAMACHA

It is a colour chart matching the mucous membrane of small ruminants with a laminated colour chart.

The pale mucous membranes indicate anemia and that the animal has a parasite burden.

Anatomy yrtwo semone (10 decks)

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