Anthelmintics Flashcards Preview

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Flashcards in Anthelmintics Deck (19)
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1
Q

anthelminitic - define

A

A chemotherapeutic agent used to control

helminth infections

2
Q

chemotherapy - define

A

Use of drugs to injure an invading organism

without injury to the host

3
Q

classification of anthelminitics

A

spectrum of activity - broad vs narrow
chemical group/mode of action
target parasites
method of delivery/formulation

4
Q

broad spec

A

Benzimidazoles – β-tubulin binding 2-LV
Imidazothiazoles – ACh agonist*
macrocyclic lactones – modulate glutamate-gated chloride channels
Amino-acetonitrile derivatives – targets specific Hco-MPTL receptors*
Spiroindole – ACh antagonist

5
Q

potency is determined by ___

A

duration of exposure

6
Q

potency

A

multiple low doses more potent than 1 large one
potency greater in ruminant/horse than dog
potency greater in ruminants if starved for 12-24h

7
Q

Imidazothiazoles/Tetrahydropyrimidines

A
yellow drench
Imidazothiazoles -levamisole
Tetrahydropyrimizines - pyrantel 
Cholinergic agonists - rapid and reversible spastic paralysis 
oral only
8
Q

levamisole - target parasites

A
Gutworms +++ 
Adult +++ 
Mucosal larvae ++ 
Hypobiotic larvae +
Lungworms +++
9
Q

pharmacokinetics - levamisole

A

v.short half life in body
injection - 8h
oral - 14h
pour-on - 24h

10
Q

macrolytic lactones (ML) - fermentation products

A

Avermectins - Streptomyces avermilitis

Milbemycins - Streptomyces cyanogriseus

11
Q

macrolytic lactones (ML)

A

clear drench
avermectins + milbemycins
Open invertebrate specific glutamate-chloride channels in post-synaptic membrane leading to flaccid paralysis

12
Q

macrolytic lactones (ML) - target parasites

A
Gutworms +++ 
Adult +++ 
Mucosal larvae +++ 
Hypobiotic larvae +++ 
Lungworms +++
arthropods ++
13
Q

ML pharmacokinetics

A

long lasting - gives period of protection against re-infection - metaphylaxis
prevents pasture contamination - prophylaxis

14
Q

roundwormers

A
benzimidazoles
macrolytic lactones
Imidazothiazoles + Tetrahydropyrimidines
aminoacetile derivatives
spiroindoles
narrow spec - depsipeptides, salicylanilides, piperazines, phenylisothiocyanates
15
Q

tapewormers

A

benzimidazoles
broad - tetrahydropyrimidines
narrow - isoquinolones, phenylisothiocyanates

16
Q

praziquantel

A

isoquinolone
Tegument destruction
Increased membrane permeability for calcium-ions, loss of intracellular Ca++
spastic paralysis and malabsorption

17
Q

flukicides

A

Salicylanilides and Substituted Phenols
Narrow Spec – fluke and blood feeding nematodes
Uncouple oxidative phosphorylation decr the availability of high energy phosphate compounds - blocks energy availability

18
Q

methods of delivery

A

oral - Drench, Paste, Tablet, in feed, Bolus (Intra-ruminal device)
parenterally - injection, subcutaneous, intramuscular
topical - tran-dermal, pour on

19
Q

benzimidazoles

A

white drench
Albendazole, (Ricobendazole) Fenbendazole, Flubendazole, Mebendazole, Oxfendazole, Triclabendazole
bind to parasite tubulin - inhibits glucose uptake - starves parasite to death
low water solubility - oral only