Anthelmintics or antihelminthics are drugs that expel parasiticworms (helminths) from the body, by either stunning or killing them. They may also be called vermifuges (stunning) or vermicides (killing).
Octadepsipeptides (eg: Emodepside) – effective against a variety of gastrointestinal helminths
Amino Acetonitrile derivatives (eg: Monepantel): effective against a variety of gastrointestinal helminths including those resistant to the other drug classes.
Please note that many of these pharameuticals are extremely toxic. Taken in improper dosages they can be dangerous to humans as well as lethal to parasites.
Natural anthelmintics
Examples of naturally occurring anthelmintics include:
Please note that many natural vermifuges or anthelmintics are poisonous and, in improper dosages, dangerous to humans as well as parasites.
Anthelmintic resistance
The ability of worms to survive treatments that are generally effective at the recommended dose rate is considered a major threat to the future control of worm parasites of small ruminants and horses.
The clinical definition of resistance is a 95% or less reduction in a "Fecal Egg Count" test.clarify
Development of resistance
Treatment eliminates worms whose genotype renders them susceptible. Worms that are resistant survive and pass on their "resistance" genes. Resistant worms accumulate and finally treatment failure occurs.