Pyrantel Pamoate

By Rania Gollakner, BS, DVM, MPH

What is pyrantel pamoate?

Pyrantel pamoate (brand names Nemex®, Nemex 2®) is an anthelmintic (dewormer). It is used to treat intestinal roundworm, hookworm, and stomach worm parasites in many species including dogs, cats, small mammals, and birds.

The use of pyrantel pamoate to treat intestinal parasites in cats is off-label. This medication is also used off-label to treat roundworms and hookworms in small mammals such as rabbits and rodents, as well as birds. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully.

Pyrantel pamoate is also found in a variety of combination products for the treatment of other intestinal parasites and/or heartworm.

How is pyrantel pamoate given?

Pyrantel pamoate is available as a capsule, chewable tablet, and liquid suspension. Pyrantel pamoate should be given by mouth with or without food. Liquid forms must be shaken well before use. Measure the dosage carefully. Follow the dosing instructions provided by your veterinarian.

This medication should take effect within one to two hours; however, effects may not be noticeably visible and, therefore, laboratory tests may need to be done to evaluate this medication’s effectiveness.

What if I miss giving my pet the medication?

If you miss a dose, give it when you remember, and then wait the amount of time between doses recommended by your veterinarian before dosing again. Never give your pet two doses at once or give extra doses.

It is very important to give the medication for the length of time your veterinarian has recommended.

Are there any potential side effects?

Side effects of pyrantel pamoate are rare when dosed appropriately, but may include nausea, vomiting, lack of appetite, and diarrhea. If vomiting occurs after receiving a dose on an empty stomach, give future doses with food.

Lack of appetite, diarrhea, and vomiting may occur due to the elimination of parasites. Contact your veterinarian if these signs become severe or continue to be a problem. This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Pyrantel pamoate should not be used in pets that are allergic to it or pets that are severely weakened or frail. It is considered safe to use in nursing animals and should be used with caution (follow the dosing instructions carefully) in pregnant animals.

Are there any drug interactions I should be aware of?

Certain drugs may interact with pyrantel pamoate including levamisole (Ripercol®, Tramisol®), morantel (Rumatel®), and piperazine (Pipa-Tabs®). Exposure to organophosphates (pesticides) while taking pyrantel pamoate should be avoided. It is important to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

Monitor to ensure that the medication is working and monitor for adverse effects.

How do I store pyrantel pamoate?

Pyrantel pamoate tablets should be stored in a tightly sealed container, protected from light, and at room temperature (15°C-30°C or 59°F-86°F). Liquid suspensions should not be exposed to direct sunlight.

What should I do in case of an emergency?

Pyrantel pamoate can be toxic when given regularly over a period of months. If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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