Ingredients in Flea Control for Cats

Never give Fluffy flea medication designed for Fido.
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If Fluffy is plagued with fleas, it's time to rid her of these pesky parasites to prevent the itching and health problems they can cause. Several flea-control products designed for felines contain ingredients to safely kill those icky fleas without hurting your kitty.

Oral Medication

Flea-killing oral medications come as tablets and liquids, containing ingredients such as nitenpyram and lufenuron to rid your little one of fleas. Nitenpyram is safe to use with kittens who are older than 4 weeks and weigh at least 2 pounds. This chemical kills all of the fleas on your furry buddy's coat within four hours, and it lasts in her system for only 24 hours. You can repeat it daily as needed. Lufenuron doesn't kill adult fleas, but it keeps immature fleas from developing into adults. This medication lasts for up to four weeks in your furry friend's system. It's usually used along with nitenpyram to get rid of both mature and immature fleas. Neither lufenuron nor nitenpyram leaves toxic residue on your feline friend's fur, according to the Natural Resources Defense Council.

Topical Medication

Topical medications designed for felines kill fleas after application, usually within 24 hours. They last four to six weeks before you need to reapply them. Such medications include ingredients such as imidacloprid, fipronil and selamectin. These flea-fighting chemicals affect the nervous systems of the tiny pests, paralyzing and killing them. Ingredients such as methoprene are sometimes combined with fipronil to prevent flea eggs and larvae from developing into adults, according to the Feline Advisory Bureau. Typically, these topically applied ingredients are safe only for kittens older than 8 to 12 weeks. Ask your veterinarian which product he recommends for your little one. Many of these products require a prescription.

Powders, Sprays and More

Flea sprays, collars and powders are available without a prescription, unlike many topical and some oral flea-control products. Most of these over-the-counter products contain pyrethrins, made from chrysanthemums. These older flea-control ingredients are not as effective or safe for our feline friends as the others on the market, and they're typically not recommended by veterinarians. Flea collars treated with these insecticides might also cause hair loss for your feline friend. In terms of treating your home to kill fleas in your kitty's environment, you can safely sprinkle flea powders containing sodium polyborate on carpets, according to the Virginia-Maryland Regional College of Veterinary Medicine.


When purchasing flea control products for your kitty, never choose those designed for dogs. These medications contain ingredients such as permethrin, a synthetic form of pyrethrin, pyrethroids, organophosphates or carbamates, all of which are toxic to kitties, according to petMD. They also contain levels of pyrethrin that are unsafe for felines. If you want to use natural products, avoid those containing essential oils -- such as orange or other citrus oils -- that are derived from plants. These oils are safe for dogs, but they're toxic for cats because their bodies can't metabolize them, warns Holisticat. When using any flea-control products, whether oral or topical, always follow the directions on the label carefully. Even very feline-safe ingredients can be toxic to kitties if used incorrectly or in larger doses than recommended for your kitty's size, warns the U.S. Environmental Protection Agency.

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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