Anthelmintics Flashcards
What are the two control/treatment options against helminths?
Anthelmintics
Non-drug related control (faecal collection, grazing strategies etc)
What are the 3 older classes of anthelmintics?
Benzimidazoles
Imidathiazoles/tetrahydropyramidines
Macrocylic lactones (avermectin and milbemycin)
What are the 2 newer classes of anthelmintics?
Amino acetonitrile derivatives
Spiroindoles
How do benzimidazoles work?
Bind to beta tubulin protein - prevents transport and release of enzymes
Are benzimidazoles absorbed well systemically? What stages of nematode do they kill?
No
Ovicidal
Also target hypobiosed larva
Give an example of a benzimidazole
Febendazole
What is the MOA for imidathiazoles/tetrahydropyrimidines
Act on nicotinic receptors of muscle cells in nematodes
Are imidathiazoles/tetrahydropyrimidines absorbed well systemically? How long are they acting?
No
Short acting - gut dwelling
Give 2 examples of imidathiazoles/tetrahydropyrimidines
Pyrantel (also used for tapeworms in horses)
Levamisole
What are the 2 categories of macrocyclic lactones and give an example of each?
Avermectins - example ivermectin
Milbemycin - example moxidectin
What is the MOA of macrocyclic lactones?
Act on nervous system on parasites, cause hyper polarisation
Are MLs well absorbed systemically? What endoparasites are they effective against?
Yes Nematodes only (but multiple stages of development)
What are 2 other important features of MLs?
Residual activity - persists for few weeks
Endectocide - kills internal and external parasites
The 2 newer classes of anthelmintics are against what parasite and in which species?
Nematodes in sheep
Give an example of an amino acetonitrile derivative
Monepantel
