Pyrantel Pamoate

Description

Pyrantel pamoate is a carbamate, one of five principal classes of deworming agents according to their chemical structure and mode of action. It has a wide margin of safety and is excellent against all common worm parasites except bots.

Pyrantel pamoate acts as a depolarizing neuromuscular blocking agent. It causes a sudden contraction, followed by paralysis of the worms causing them to "lose their grip" on the intestinal wall and be passed out of the horse's system by natural process. Outside the host's body the worm soon dies.

Usage

Pyrantel pamoate is used as a deworming agent in the treatment of large strongyles (Stronglylus vulgaris, S. edentatus, S. equinus); small strongyles (Trichonema spp and Triodontophorus spp.); pinworms (Oxyuris equi, Probstmayria vivipara); large round worms (Parascaris equorum); and tape worms ( Anoplocephala perfoliata).

Only the worms in the intestine are vulnerable to pyrantel pamoate. This means that the deworming must be repeated 2-4 weeks after the first deworming and possibly a third deworming 2-4 weeks after that to be fully effective.

Some drug companies pair pyrantel pamoate with praziquantel for tapeworms and sometimes febantel for whipworms in order to provide a more complete treatment, since pyrantel pamoate alone is not effective against whipworms and the dose needs to be doubled to treat for tapeworms.

Pyrantel pamoate is safe to use with foals over 4 weeks of age, and pregnant and nursing mares.

Dosage and Administration

Side Effects

Worms may be passed with some diarrhea and/or straining. A horse with a large number of worms may suffer an impaction when a large number of worms die and try to pass at the same time. If you know your horse has a large number of worms, some veterinarians suggest giving a laxative prior to the administration of a dewormer.

Precautions

Pyrantel pamoate should not be used in debilitated animals or foals less than 4 weeks old.

It is not for use in horses intended for human consumption.

Pyrantel pamoate is a prescription drug approved by the FDA for use in horses. It is a prescription drug restricted to use by or on the lawful written or oral order of a licensed veterinarian.

Check with the appropriate regulatory body regarding use in competition horses.

Interactions

Pyrantel pamoate should not be used with levamisole, morantel or piperazine dewormers or with organophosphate insecticides because of the danger of increased side effects.

Overdose

In the event of an overdose, contact your veterinarian immediately and follow any directions given on the manufacturer's information.