Anthelmintics (vermifuges) are drugs used to control parasitic helminths (worms). They are used in both human and veterinary medicine. Treatment with an anthelmintic is also called worming or deworming.
What are anthelmintics?
Medicinal plants with anthelmintic activity include the Native American wormweed and the native tansy. The flowers and seeds of these plants contain essential oils that have been used in traditional folk medicine as broadly effective dewormers. Anthelmintics are usually substances that act as specific poisons on various vital functions of the worms, while for humans they are, if not free of side effects, largely harmless. They are taken orally and exert their effect in the intestine, the worms’ habitat. The term anthelmintic describes a spectrum of different active ingredients. There are anthelmintics that are generally effective against cestodes (tapeworms) or nematodes (threadworms), and anthelmintics that are predominantly active against one type of worm. Cestodes include the cattle, pig and dog tapeworms relevant to humans. Nematodes include roundworms, pinworms and hookworms, which also affect humans.
Medical application, effect and use
Anthelmintics are intended for oral intake, and come in tablet or juice form. In the homeopathic pharmacy, anthelmintic globules are available. So-called worm herbs – medicinal plants effective against worms – are usually administered in the form of teas. Most anthelmintics are effective only against worms, but not against their eggs. Their effectiveness against tapeworm fins is also limited. These larval stages of dog or fox tapeworm, encapsulated in the liver, lungs, and more rarely other organs, cause the clinical picture of echinococcosis. If surgical removal of the fins is not possible, long-term treatment with an anthelmintic can at least slow the progression of the disease. When controlling intestinal parasites, the life cycle of the worms must be considered. In the case of infestation with the bovine and porcine tapeworm, single doses of a suitable anthelmintic are sufficient, since here the eggs do not pose an immediate danger to humans. In the case of pork tapeworm, however, this is only true to a limited extent; cases of echinococcosis caused by pork tapeworm fins have also been reported. In the case of roundworms and pinworms, all life stages of the worm are found in the human host. The first larvae hatch from swallowed pinworm eggs after two to three weeks in the intestine and develop into worms within about two more weeks. Roundworm larvae, after piercing the intestinal wall, travel in the liver, blood vessels and lungs for about a week until they arrive back in the intestine and become adult worms. Since anthelmintics are not or only slightly effective against eggs and larvae, it is recommended to repeat the treatment at least once. In the case of roundworm infestation, the anthelmintic should be taken again after two to three weeks in order to also kill the new tapeworms that have developed from the surviving larvae. The most effective treatment for persistent pinworm infestation is weekly administration of an anthelmintic for at least four weeks. This really kills all the post-maturing worms.
Herbal, natural and pharmaceutical anthelmintics.
Pharmaceutical agents commonly used as anthelmintics include mebendazole (trade names: Vermox, Surfol), praziquantel (Biltricide, Cesol, or Cysticide), ivermectin (Stromectol), pyrantel (Helmex), and pyrvinium (Molevac, Pyrcon). Mebendazole, ivermectin, and pyrantel are effective against pinworms, roundworms, and hookworms. Praziquantel is effective against tapeworms. Pyrvinium is used to treat pinworm infections specifically. Sites of attack and mechanisms of action of anthelmintics are different. Praziquantel, ivermectin, and pyrantel immobilize threadworms and tapeworms so that they are excreted in the stool. Mebendazole and pyrvinium block nutrient absorption in the worms’ intestines. Medicinal plants with anthelmintic activity include Native American wormweed, native tansy, wormseed – a species of mugwort native to the Near East – and wormseed glandular goosefoot. Flowers and seeds of these plants contain essential oils that have been used in traditional folk medicine as broadly effective dewormers.However, due to the toxicity of these plants, self-medication is not recommended. These medicinal plants are the raw material for a number of homeopathic medicines against worms. Tinctures of wormweed, wormseed, and wormseed glandular goosefoot are commonly used as worm remedies in homeopathy under the names Spigelia anthelma, Cina maritima, and Chenopodium anthelminthicum; furthermore, Artemisia abrotanum, the boar’s rue.
Risks and side effects
For a one-time deworming, the side effects of anthelmintics usually do not play a major role. Abdominal pain, nausea, vomiting, headache, muscle pain, and rare allergic reactions in cases of hypersensitivity to the active ingredient of the anthelmintic are typical side effects. However, when used in long-term therapy of echinococcosis, these side effects can significantly reduce general well-being and also stress the liver and kidneys. Some anthelmintics have been shown to be harmful to fertility in experiments with laboratory animals. Treatment with mebendazole during pregnancy is therefore not recommended; therapy with praziquantel, pyrvinium and pyrantel is possible under medical supervision after careful consideration of the options. If deworming is necessary during lactation, breast milk must be pumped and discarded during treatment.
