Pyrantel is a medication used to treat a number of

parasitic worm infection Helminthiasis, also known as worm infection, is any macroparasitic disease of humans and other animals in which a part of the body is infected with parasitic worms, known as helminths. There are numerous species of these parasites, which are br ...

s. This includes

ascariasis Ascariasis is a disease caused by the parasitic roundworm ''Ascaris lumbricoides''. Infections have no symptoms in more than 85% of cases, especially if the number of worms is small. Symptoms increase with the number of worms present and may in ...

hookworm infection Hookworm infection is an infection by a type of intestinal parasite An intestinal parasite infection is a condition in which a parasite infects the gastro-intestinal tract of humans and other animals. Such parasites can live anywhere in the ...

enterobiasis Pinworm infection (threadworm infection in the UK), also known as enterobiasis, is a human parasitic disease caused by the pinworm (parasite), pinworm, ''Enterobius vermicularis''. The most common symptom is pruritus ani, or itching in the Human ...

(pinworm infection), trichostrongyliasis, and

trichinellosis Trichinosis, also known as trichinellosis, is a parasitic disease caused by roundworms of the ''Trichinella'' genus. During the initial infection, invasion of the intestines can result in diarrhea, abdominal pain, and vomiting. Migration of la ...

. It is taken by mouth. Side effects include nausea, headache, dizziness, trouble sleeping, and rash. A lower dose should be used in people with liver disease. While it does not appear to be harmful during

pregnancy Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs ...

, it has not been studied for this use. It is unclear if it is safe for use during

breastfeeding Breastfeeding, also known as nursing, is the process where breast milk is fed to a child. Infants may suck the milk directly from the breast, or milk may be extracted with a Breast pump, pump and then fed to the infant. The World Health Orga ...

. It is in the

antihelmintic Anthelmintics or antihelminthics are a group of antiparasitic drugs that expel parasitic worms (helminths) and other internal parasites from the body by either stunning or killing them without causing significant damage to the host. They may also ...

family of medications. It works by paralyzing worms. Pyrantel was initially described in 1965. It is on the

World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health s ...

. Pyrantel is available as a

generic medication A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active ch ...

. It may also be used to treat worms in a number of other animals.

Pregnancy and breastfeeding

Pyrantel pamoate is considered a

pregnancy category The pregnancy category of a medication is an assessment of the risk of fetal injury due to the pharmaceutical, if it is used as directed by the mother during pregnancy. It does ''not'' include any risks conferred by pharmaceutical agents or their ...

C drug for use during pregnancy for humans, but is in category A for canines and felines. Pyrantel is considered safe to use in nursing animals.

Mechanism of action

Pyrantel pamoate acts as a

depolarizing neuromuscular blocking agent Neuromuscular-blocking drugs, or Neuromuscular blocking agents (NMBAs), block transmission at the neuromuscular junction, causing paralysis of the affected skeletal muscles. This is accomplished via their action on the post-synaptic acetylcho ...

, thereby causing sudden contraction, followed by paralysis, of the

helminths Parasitic worms, also known as helminths, are a polyphyletic group of large macroparasites; adults can generally be seen with the naked eye. Many are intestinal worms that are soil-transmitted and infect the gastrointestinal tract. Other par ...

. This has the result of causing the worm to "lose its grip" on the intestinal wall and be passed out of the system by natural process. Since Pyrantel is poorly absorbed by the host's intestine, the host is unaffected by the small dosage of medication used. Spastic (tetanic) paralyzing agents, in particular pyrantel pamoate, may induce complete intestinal obstruction in a heavy worm load. This obstruction is usually in the form of a worm impaction and happens when a very small, but heavily parasitized animal is treated and tries to pass a large number of dislodged worms at once. Worms usually pass in normal stool or with diarrhea, straining, and occasional vomiting.

Names

There are a number of brands, including "Reese's Pinworm Medicine", "Pin-X", "Pin-Rid", "PYRANTRIN", "COMBANTRIN", "Anthel", "Helmintox", "Helmex", "Strongid", Konvermex, and Drontal Cat.

References

External links

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