What Is Pyrantel?

Pyrantel is an antiworm medication used to eliminate certain parasitic worms in animals and humans. Like most antinematodal medications, this drug does not actually kill the parasites but rather renders them immobile, causing the worms to detach from the intestinal wall. Once detached, the worms are eliminated through bowel movements.

The use of pyrantel is common in veterinary medicine. The drug is given by ingestible paste for bloodworm and roundworm treatment in horses. Additionally, both liquid and pill forms of the drug are available for most domesticated animals for heartworm and hookworm treatment and prevention. In general, medications made from the drug are considered safe in animals.

In humans, pyrantel is most often used in pinworm treatment and is approved as an over-the-counter treatment for the condition in many countries. Patients taking pyrantel for pinworms should be aware that the medication does not kill the eggs of the parasite. Repeat treatments are required to completely rid the body of the worms.

Reoccurring infestations are common in both humans and animals even after successful pyrantel treatments. Parasite eggs can remain viable for extended periods of time and can be easily overlooked in normal cleaning. In addition, those in continual close contact with a contaminated individual may also be infected. As such, all family members of an individual should be treated simultaneously. Great care should also be given to thoroughly cleanse the living area, preferably using products designed specifically for parasite removal.

Gastrointestinal side effects are common with pyrantel use. Nausea and stomach cramps are frequent but can often be reduced in severity by taking the drug with food or milk. Vomiting and diarrhea are also commonly noticed. Bloody stools or excessive vomiting may be signs of a dangerous complication and should be reported at once.

Obstruction of the bowels is rare but possible shortly after taking pyrantel. When large colonies of parasitic worms are dislodged at one time, they can form a mass that impacts the lower intestines. This condition is more common in animals but can rarely occur in humans. Patients that experience constipation after taking this medication are advised to contact a medical professional.

Drowsiness and vertigo have been reported by patients who have been prescribed pyrantel. These side effects are generally mild and do not require additional medical treatment. In addition, this medication may cause irritation of the digestive tract and subsequent uterine contractions. For this reason, most pregnant women are advised against its use.