Drugs to Treat Internal Parasites in Cats

I don't like the pill, but it's better than the worms.
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If your Kitty suffers from parasites, drugs known as anthelmintics can rid him of these pests. No matter how well you take care of Kitty, parasites are always a possibility, especially if he goes outside or comes into contact with other cats or dogs.

Common Parasites

Even newborn kittens get internal parasites -- in fact, it's very common. Common worms found in cats or kittens include tapeworm, hookworm and roundworms -- also known as ascarids -- along with microscopic creatures such as giardia and coccidia. You might see certain worms in Kitty's feces. If your cat appears to have rice particles near his anus, those are actually tapeworm segments. Bring a stool sample to your vet so she can check it for parasites and give Kitty the proper medications to get rid of them.


The majority of the time, you aren't going to see worms coming out of Kitty, and certain parasites are too small to see with the naked eye. Kittens with worms often have a potbellied, unhealthy appearance. Other symptoms of parasite infection include vomiting and diarrhea, tarry feces, anemia and skin problems. While you can purchase many broad-spectrum dewormers over the counter, take Kitty to the vet so you know exactly what type of parasites you're dealing with, since even broad-spectrum dewormers don't get rid of everything.


This over-the-counter dewormer kills roundworms in cats. It's available in pills, pastes and liquid versions, either mixed with food or put directly in Kitty's mouth. It's safe for pregnant cats, but don't give it to kittens under 6 weeks old. Ask your vet before giving piperazine to sick cats or those with compromised immune systems. Don't give it to cats with liver or kidney disease.


If Kitty has tapeworms, praziquantel, available in tablets over the counter, can get rid of them. One or two treatments might be needed to complete the deed. Since cats get tapeworms from fleas, you should use praziquantel in conjunction with effective flea control, such as a topical monthly flea medication. Your vet can give Kitty a praziquantel injection.

Pyrantel Pamoate

Pyrantel pamoate doesn't actually kill roundworms, but it paralyzes them so the little critters lose their grip on Kitty's intestine and end up eliminated in his feces. It also gets rid of hookworms. A prescription version combined with praziquantel and other anthelmintics is called Drontal. While pyrantel pamoate is safe for kittens and pregnant and lactating cats, don't combine it with piperazine.


Selamectin, a topical flea medication sold under the brand name Revolution, also keeps Kitty safe from heartworm, hookworm, roundworms and ear mites. It's available only by veterinary prescription.

Other Medications

If Kitty has the intestinal parasite giardia, your vet might prescribe the drug metronidazole. Another treatment is the anthelmentic fenbendazole, available over the counter. For coccidiosis, your vet might give Kitty trimethoprim-sulfa for approximately six days to rid him of this organism.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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