Changes

This class of drugs are known by farmers as white drenches. The product code in the UK is '''1-BZ'''. The most commonly used drugs in this category are; '''albendazole, fenbendazole''' and '''oxfendazole'''.

This class of drugs are known by farmers as white drenches. The product code in the UK is '''1-BZ'''. The most commonly used drugs in this category are; '''albendazole, fenbendazole''' and '''oxfendazole'''.

==Spectrum of Activity==

==Spectrum of Activity==

* '''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 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.

* 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==

==Pharmacokinetics==

* 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.

* 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.

* 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.