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→Spectrum of Activity
* Albendazole and fenbendazole are active against [[protozoa|Giardia]].
* Albendazole and fenbendazole are active against [[protozoa|Giardia]].
* '''Triclabendazole''' is active against all stages of ''Fasciola hepatica'', but inactive against nematodes and cestodes.
* '''Triclabendazole''' is active against all stages of ''Fasciola hepatica'', but inactive against nematodes and cestodes.
* They
* They work by binding to tubulin. This caps the ends of microtubules in the parasites, resulting in disruption in their intestinal and integumental cells. Thus they can't utilise glucose efficiently and they starve to death.
==Pharmacokinetics==
* They kill the parasites slowly and so potency is determined by the duration of exposure not peak plasma concentration.
* So the more soluble the drug the less potent it is.
* Multiple low doses are better than one large dose.
* They work better in ruminants and horses than carnivores. This is because the rumen and caecum act as reservoirs for the drug.
* In ruminants, the potency is increased by starving them for 12-24 hours, as the transit time through the gut will be increased. This is the opposite in carnivores.
* These drugs are often given in a pro-drug form which is metabolised to the sulphoxide form of the drug (the most potent form) and then to the inactive sulphone form. '''Netobimin''' is the prodrug of albendazole, whilst '''febantel''' is the prodrug fenbendazole.