How to Treat a Cat's Worms

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Some kittens may be too young for deworming medication.
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Intestinal parasites, also commonly called "worms," can cause all kinds of health problems for your feline friend. After diagnosing your cat with intestinal parasites, your vet can prescribe a medication targeted to the specific type of parasite attacking Fluffy. These medications may require more than one dose and are typically given orally. Your vet will give you exact instructions to get your kitty parasite-free.


The ingredients pyrantel pamoate, fenbendazole, emodepside, milbemycin oxime, moxidectin and selamectin, all commonly found in most prescription deworming medications, will kill your cat's roundworms. Another ingredient, piperazine, is commonly found in over-the-counter products and will kill roundworms as well. While most of these medications kill the roundworm species Toxocara cati, some, like selamectin and milbemycin oxime, don't kill Toxascaris leonina. These medications anesthetize the roundworms, causing them to lose their grip on your cat's intestines. Your cat then eliminates the roundworms in her stool, so you may find them in her feces during treatment. Most of these medications are given orally in a single dose and may require a second or third dose every two to three weeks.

Hookworm Eradication

Hookworms are killed by most of the same ingredients that get rid of roundworms, which can get rid of both pests at the same time. These medications include fenbendazol, emodepside, pyrantel pamoate, milbemycin oxime, moxidectin and selamectin. Hookworms also can be treated with ivermectin, a medication which kills heartworms as well. All hookworm medications eliminate the hookworms only in the gastrointestinal tract. A second dose given after two to three weeks will kill any parasites that were migrating through your cat's tissues at the time of the first deworming.

Eliminating Tapeworms

Most medications that eliminate hookworms and roundworms won't get rid of tapeworms. Praziquantel is one of the drugs that kills tapeworms in cats. It's usually given in tablet form as a single dose to your cat. This medication dissolves the tapeworms in your cat's intestines. As with other deworming medications, you may need to repeat the dose after two to three weeks to kill any remaining tapeworms in your cat's system. Many times, praziquantel is combined with pyrantel pamoate in broad-spectrum dewormers to kill roundworms and hookworms as well. Your vet likely will recommend a flea preventative medication for your kitty because some types of tapeworms are spread by fleas.

Preventing Worms

Clean your cat's environment, removing any feces from outdoor areas she has access to. Your vet may recommend putting your cat on a monthly preventative medication such as selamectin, which is applied topically between your cat's shoulder blades, to keep her parasite-free. Selamectin kills hookworms and roundworms. It also kills fleas, which will help to prevent tapeworms, although it won't kill tapeworms in your cat's system.

Medication Safety

Not all deworming medications are safe for pregnant and nursing cats or very young kittens. Most oral medications, such as praziquantel, ivermectin and milbemycin oxime are only safe for use in kittens at least 6 weeks old. Selamectin is safe for use in kittens at least 8 weeks old and pregnant and nursing cats. Pyrantel pamoate, ivermectin and praziquantel are all safe to use in pregnant and nursing cats. Always ask your vet whether the medication he's prescribing is safe for your pregnant, nursing or kitten. Never use deworming medications for dogs on cats because their ingredients and dosages may be unsafe for felines.

Ringworm Treatment

Note that ringworm is not an intestinal parasite, but rather a type of fungal skin infection in cats. Your vet will recommend a topical anti-fungal medication to treat it.