How Do Common Tick Medications Work?

Kimberly Porter
Apr 11, 2012
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Types of Tick Preventives

If you and your pet spend a lot of time roaming outside during the spring and summer months, you have no doubt removed your fair share of ticks. Ticks are not only unsightly and gross they can also carry diseases, transmitting them to your pet as they feed. There are many options available to repel ticks and keep your pet more comfortable during peak tick season.

1. Pyrethrins

Pyrethrins have been used for more than 100 years and take aim at the nervous system of ticks by causing repetitious rapid nerve impulses, resulting in death. They are naturally occurring chemicals, extracted from chrysanthemum flowers, and are not limited to tick control. Pyrethrins also can be used to control fleas, lice, some mites, and mosquitoes. Because they have a low toxicity, pyrethrins are used in products that can be applied directly to the pet’s skin. You can find pyrethrins as active ingredients in shampoos, dips, powders, and spray formulations.

2. Pyrethroids

Similar to pyrethrins, pyrethroids are a synthetic group of chemicals that have a longer-lasting effect. They also work in the same way that pyrethrins do, resulting in the death of insects as well as repelling insects. Pyrethroids are typically used with an oil carrier to be applied as a spot-on product for dogs. Cats are often sensitive to many pyrethroids, so care must be taken when choosing a proper tick preventive for your cat or kitten.

3. Citrus Extracts

Citrus pulp extracts (such as d-limonene and linalool) also cause a reaction in the insect’s nervous system, repelling them. You will find citrus extracts in shampoos, dips, and sprays. As they are created from a natural source, citrus-derived products may be less toxic, but they may also be less effective. As with pyrethroids, be careful with citrus products, as cats are especially sensitive to citrus extracts.

4. Fipronil and Selamectin

These synthetic compounds cause a blockage of chemical transmission in the tick’s nervous system, leading to paralysis and death. Fipronil and selmectin are usually mixed with an oil to be applied as a spot-on, allowing the product to stay in contact with the animal and release itself slowly over time. Selamectin has the added ability to absorb into the bloodstream, where it kills internal parasites as well, including the parasite that causes heartworm disease in dogs and cats.

5. Carbamates and Organophosphates

These two compounds work by inhibiting the normal function of a necessary enzyme in the tick’s nervous system. Carbamates and organophosphates are often used in conjunction with pyrethrins to delay their breakdown. They are found typically as active ingredients in tick sprays, dips, and collars.

6. Amitraz

One highly effective ingredient used in dog tick collars is amitraz. It is also found as an ingredient in dips used to treat mange. This chemical has no effect on fleas, but kills ticks by absorbing into the animal’s skin and will prevent ticks from attaching in most cases. Amitraz works by inhibiting signals in the tick’s nervous system. (Warning: Products containing amitraz should not ever be used on cats.)

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