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Using Flea and Tick Preventive Products Made for Dogs and Cats

By Jennifer Kvamme, DVM

Preventive Product Basics

Both cats and dogs need to be given preventive products for fleas and ticks. If you are the head of a household where cats and dogs reside together, you may be tempted to get one flea and tick treatment for both. It’s important that you do your research carefully before using any product on your pets that has not been explicitly prescribed for them, and this is particularly the case with flea and tick treatments. Cats and dogs have different physiologies and these products affect them differently. Canine formulations of flea and tick preventive products can be lethal for cats, so you can not use the same medication on your dog as your cat -- unless it has been specifically formulated for both species.

There are some products that come in both a cat and dog version, but you still need to read the labels carefully to make sure you are using a product that is labeled for use in cats before applying it on, or giving it to your cat. Cats can become very ill and even die from an incorrect application of dog flea and tick treatment.

The following are some of the more common products on the market.


Cats are notoriously sensitive to pyrethroids, a common synthetic ingredient used in flea and tick products. These man-made chemicals are related to the pyrethrins, which are natural products derived from the flower of the chrysanthemum plant. While pyrethrins are safe to use in the proper dosage, cats have a low tolerance for the synthetic pyrethroid products.

Pyrethroids are typically found in spot-on products made for dogs. They can also be found in sprays meant for treating the home. Another name for pyrethroid chemicals that is commonly seen listed on flea and tick products is permethrin, which is typically found in flea and tick shampoos and mosquito control products for dogs.

If you do have both cats and dogs in your home and you are going to use a flea and tick product on your dog, be sure to keep the animals apart to prevent accidental contact until the medication has had time to dry on the dog’s body.

Citrus Extracts

Other plant-derived flea and tick products need to be used with care around cats. Citrus extract products (such as limonene and linalool) are made with oils from citrus. Cats are much more sensitive to citrus oils than dogs are. These products are found in shampoos, sprays, dips, and insect repellants. Toxicity with these products occurs at a very low dose in cats and can result in liver damage, liver failure, and even death.


Another class of chemicals that can be found in flea and tick treatments are the organophosphates. These chemicals are very toxic to cats. You may find that some household sprays contain organophosphates; these sprays should not be used in homes where cats are present. Examples of common organophosphates used in flea collars and dips (as well yard care insecticides) include diazinon, chlorpyrifos, fampfhur, coumaphos, cyothioate, malathion, terbufos, and fention.

Read Labels Carefully

When considering a flea and tick preventive product for your cat, always read the label carefully to be sure the product is labeled for use in cats. When treating very young animals, those that are very old or debilitated, and those that are pregnant or nursing, always ask for your veterinarian's advice before choosing a product (this is true whether you are treating a cat or a dog). The instructions on the label should be followed closely when applying or giving any type of medication to your cat.

After you have given your cat the flea and tick treatment -- either pill, spot on or otherwise -- watch the cat for a time after to monitor for any adverse effects, such as drooling, stumbling, loss of coordination, seizures, etc. If any unusual signs appear, or if your cat behaves in any way out of the ordinary, wash the cat off with a light soap and rinse the coat thoroughly with water. Follow this immediately with a visit to your veterinarian for a check-up and treatment if needed.

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