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How Does Advantage Work to Control Fleas?

| Updated September 26, 2017

When it comes to monthly topicals for your dog, they're not all the same, even though they may look similar. In fact, the same manufacturer, Bayer, makes different versions of the same product, Advantage, for different uses. Advantage works to eradicate fleas, while Advantage Multi takes on other parasites, including heartworm. Follow the directions for safe use and contact your vet with questions or concerns.

Advantage's Active Ingredient: Imidacloprid

Advantage uses the active ingredient imidacloprid to do the heavy lifting when it comes to flea control. Similar to other compounds used in other flea preventives, imidacloprid works by paralyzing and eventually killing the insects. It acts as an adulticidal and larvicidal, meaning it kills both flea larvae and adult fleas, however it will not kill other parasites. It doesn't take long for Advantage to go to work: In 12 hours at least 98 percent of the fleas on your dog will be dead. Puppies younger than 7 weeks of age and pregnant dogs should not use Advantage.

Imidacloprid + Moxidectin = Advantage Multi

When you add moxidectin to the mix, you get a topical that not only kills fleas but also treats sarcoptic mange, hookworms, whipworms and roundworms. Advantage Multi also helps control heartworm because it's effective at killing microfilaria. Puppies under 7 weeks of age and heartworm-positive dogs should not use Advantage Multi. Certain breeds of dogs, such as collies, Australian shepherds and mixes containing those breeds tend to have a multidrug resistant gene mutation making them especially sensitive to the class of drugs containing moxidectin, potentially causing very serious reactions to the drug.

Using Advantage Products

Both Advantage and Advantage Multi are applied monthly to the dog's skin at the base of the skull or the back of the neck to ensure he isn't able to lick the medication. When the liquid makes contact with the skin, it spreads over the body, collecting in hair follicles to be released over a month's time. When the target of the insecticide comes in contact with the active ingredients, it absorbs the poison, eventually dying. If you bathe your dog regularly, or he enjoys a good swim, he'll still enjoy the benefits of the topical as it remains on his body after exposure to water or sunlight.

Side Effects and Cautions

The most common side effect of Advantage is drooling, a reaction from the bitter taste if a dog has licked the medication before it's had a chance to dry. Otherwise, side effects are rare and occur if large amounts are ingested, resulting in twitching and muscle weakness. Advantage Multi's potential side effects include decreased appetite, lethargy, hyperactivity and attention to the application site. If your dog ingests the medication he may salivate, become uncoordinated and depressed and experience tremors and panting. If he gets either product in his eyes, flush his eyes thoroughly with water. If you suspect your dog is having an adverse reaction to a flea topical, call the vet immediately.