How does Frontline work?

When I first started researching spot-on topical flea and tick treatments for cat and dogs, and in particular Frontline Plus, I asked, “How does Frontline work?”

This is really a two part question in my mind. First, you need to know the Frontline Plus ingredients and how they work together to kill fleas and prevent flea bites.  Second, you need to understand how the medicine is applied and distributed across the entire body of the animal.

Formula & Ingredients: How does Frontline work?

In a previous post on the Flea Bites 101 blog, we discussed Frontline Plus ingredients and how they work.  So, I will not get too involved here and simply provide a brief summary.

The Frontline Plus formula contains fipronil and (S)-methoprene.  You can learn more about what they do in the post linked above.  In short, fipronil kills adult fleas and (S)-methoprene kills flea eggs and larvae.  Because it kills in all stages of the flea life cycle, Frontline Plus is arguably the market leader in the flea control market. Please see our review of the leading players in the spot-on topical treatment category so that you can find the best flea treatment for dogs and cats.  The results may surprise you.

How does Frontline Plus spread from one spot to the entire body?

Though I earned an A in anatomy and physiology while in college, I am not a science whiz.  When I first heard about spot-on topical treatments I was incredibly skeptical about how effective they could be.  The directions for Frontline Plus state that you are supposed to apply the entire dosage to one area on the back of the neck.  A quick aside – K9 Advantix II should be applied in multiple areas per directions.

So, how does the medicine mysteriously work its way across the entire body to provide protection and relief from fleas and ticks?

Through a process called translocation, the medicine is absorbed by sebaceous glands. These glands secrete an oily/waxy matter, called sebum, which lubricates and waterproofs the skin and hair of mammals. The flea medication essentially mixes with the sebum and is transported throughout the body similarly to how the American railroad system connected the United States.

You will often read on packaging for spot-on treatments that the medicine is waterproof.  That is because the medicine is absorbed into the body and cannot be washed away.  However, you are usually discouraged or advised to refrain from bathing your cat or dog for at least 24 hours after administering the dosage so that you can ensure that the medicine is fully absorbed.

One more important note.  Make sure that when you apply the medicine to your cat or dog that you part the coat and apply it directly to the skin  You do not want to simply apply it to the outer coat or in the middle of the coat as this will delay or hinder absorption.