Pyrantel pamoate is an anthelmintic or dewormer that is used off-label to treat intestinal parasites in cats. It acts as a neuromuscular blocker, paralyzing parasitic worms and causing them to lose their attachment to the host’s intestine. Pyrantel for cats is used to treat and prevent roundworms and hookworms, though it is not effective against whipworms or tapeworms. It is also found in various combination products for the treatment of intestinal parasites and/or heartworm.
Pyrantel for cats is available over the counter in 22.7 mg and 113.5 mg tablets, and in 2.27 mg/ml, 4.54 mg/ml, and 50 mg/ml liquid suspensions. Prices vary depending on the dosage and size. A 22.7 mg tablet costs about $1.30, a 113.5 mg tablet about $6.80, and a 60-ml bottle of 4.54 mg/ml suspension about $20.
Pyrantel pamoate is typically dosed in cats as follows:
- 2.5 to 5 mg per pound (5 to 10 mg per kilogram) once, then repeated in 2 to 4 weeks.
Note that the size of the medication is not an indication of a proper dose. Always consult your veterinarian before administering pyrantel and follow the dosing instructions provided by them.
Liquid pyrantel for cats has a pleasant taste and may be easier to administer than the tablet form. Liquid medicines must be shaken well before use. Measure the dosage carefully as instructed by your veterinarian.
For treatment: Roundworms and hookworms migrate through the host’s body and complete their development in the intestine. Since pyrantel pamoate only treats worms in the intestine, a second deworming is necessary after 2 to 4 weeks in order to address those that are still in the process of migration. In some cases, a third deworming may be needed 2 to 4 weeks after the second one.
To measure the efficacy of pyrantel against intestinal parasites in cats, one study examined 30 cats of different breeds and ages with natural and/or induced infections of Ancylostoma tubaeforme (a hookworm species) and Toxocara cati (the feline roundworm). The cats either received no medication, pyrantel in paste form, or pyrantel in granule form.
The study found that the paste formulation was 99.3% and 99.7% effective in reducing fecal egg counts of A. tubaeforme and T. cati respectively, while the granule formulation was 97.7% and 99.9% effective in reducing fecal egg counts of A. tubaeforme and T. cati respectively. When it came to eliminating adult worms, the paste form was 99.5% and 100% effective against A. tubaeforme and T. cati respectively, while the granule form was 97.9% and 100% effective against A. tubaeforme and T. cati respectively. No toxic effects were observed for either formulation.
Another study, which ran a similar trial, had similar results. It also evaluated the clinical safety of pyrantel pamoate in 30 young kittens, who either received no medication or pyrantel in paste or granule form at 100 mg per kilogram for 3 consecutive days. No adverse effects were seen in the kittens who received a high dose of pyrantel pamoate.
Side effects of pyrantel for cats may include:
Pyrantel is a short-acting medication that should stop working within 24 hours, though effects can be longer in cats with kidney or liver disease. Most of the above signs are due to the elimination of worms. If they persist or become severe, contact your veterinarian.
Pyrantel for cats is considered safe to use during pregnancy and lactation. It should not be used in cats who are severely weakened or frail, or with other dewormers. Exposure to organophosphate insecticides while taking pyrantel should be avoided as well. Additionally, anyone who is deworming their cat should be mentally prepared for the possibility of seeing roundworms being passed alive.
Pyrantel pamoate (Nemex, Strongid) may interact with the following medications:
- Anthelmintic drugs (levamisole, morantel, piperazine)
- Organophosphate insecticides
Always tell your veterinarian about any medications, vitamins, supplements, or herbal therapies that your cat is taking before administering pyrantel.
Allergic reactions and sensitivity
Cats who are allergic to pyrantel should not take this medication.
Frequently asked questions
Do I need a prescription for pyrantel?
No, pyrantel pamoate is an over-the-counter drug.
How do I store pyrantel pamoate?
Pyrantel tablets should be stored in a tightly sealed container at room temperature, away from light. Liquid suspensions should be kept away from direct sunlight.
What do I do if I miss a dose?
If you accidentally skip a dose of pyrantel, simply give it when you remember. Never give your cat extra doses; wait the amount of time between doses recommended by your veterinarian before giving the next dose.
What should I do in case of emergency?
If you suspect your cat has overdosed or is having an allergic reaction to pyrantel pamoate, bring them to your veterinarian or an emergency facility immediately.