Anthelmintics Flashcards
What is the function of anthelmintics?
To control and treatment of parasitic infections
What are the considerations of anthelmintics that need to be taken into account before use?
Spectrum of activity, pharmacokinetics, formulation, administration, drug efficacy, resistance, toxicity/specificity vs host/cost
What are the 5 major classes of anthelmintics for sheep?
1-Benzimidazoles- (1BZs) 2- Imidathiazoles/tetrahydropyrimidines (2LEV) 3-Macrocyclic lactones (3MLs) 4- Amino acetonitrile derivatives (4ADs) 5- Spirondoles (5SIs)
What is the mode of action of benzimidazoles?
Bind to microtubule subunit protein B- tubulin, inhibit microtubule-mediates transport of secretory vesicles, prevents transport therefore enzyme released
What are some examples of benzimidazoles?
Fenbendazole, Albendazole, flubendazole, mebendazole
Febantel- pro drug (activated in body)
Triclabendazole
What are benzimidazoles spectrum of activity like?
Not well absorbed systemically
Primary target nematodes (round worms)
Can kill eggs- ovicidal
Effective at targeting hypobiosed larvae
What is the mode of action of Imidathiazoles/tetrahydropyrimidines?
Act on nicotinic acetyl choline receptors- somatic muscle cells
What are 3 examples of LEVs?
Levamisole, Pyrantel, Morantel
How good is Imidathiazoles/tetrahydropyrimidines spectrum of activity?
Not well absorbed systemically
Primary targets nematodes- gut dwelling stages
Short acting
What are the two classes of macrocyclic lactones?
Avermectins
Milbemycins
What are some examples of avermectins?
Ivermectin, doramectin, eprinomectin, selamectin
What are some examples of Milbemycins?
Moxidectin, milbemycin oxime
What is macrocyclic lactones mode of action?
Act on nervous system of parasite- musculature and pharyngeal pumping
Potentiators causing hyperpolarisation
Describe macrocyclic lactones spectrum of activity?
Well absorbed systemically, effective against nematodes, target multiple nematode stages- migrating larvae, hypo biotic larvae, long lasting
What are amino acetonitrile derivatives spectrum of activity like?
Targets adult/L4 larvae of most important species
Effective against species resistant to 1-BZ/2-LEV/3ML
Short acting
