are drugs that expel parasitic worms
) from the body, by either stunning or killing them. They may also be called vermifuges
(stunning) or vermicides
Examples of pharmaceuticals used as anthelmintics include:
- Albendazole – effective against threadworms, roundworms, whipworms, tapeworms, hookworms
- Diethylcarbamazine – effective against Wuchereria bancrofti, Brugia malayi, Brugia timori, tropical pulmonary eosinophilia, loiasis
- Mebendazole – effective against pinworms, roundworms and hookworms
- Niclosamide – effective against tapeworms
- Ivermectin – effective against most common intestinal worms (except tapeworms)
- Thiabendazole – effective against roundworms, hookworms
- Pyrantel pamoate – effective against most nematode infections
- Piperazine family
- Praziquantel – effective against nematodes, some trematodes
- Triclabendazole – effective against liver flukes
- 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.
Examples of naturally occuring anthelmintics include:
Please note that many natural vermifuges or anthelmintics are poisonous and, in improper dosages, dangerous to humans as well as parasites.
The ability of worms to survive treatments that are generally effective at the recommended dose rate is considered a major threat to the current 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.
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.