Advantage II for Cats is a reformulated version of Advantage for Cats. The new version adds a second ingredient to stop the development of flea eggs, while still killing adult fleas within 12 hours. It continues to kill fleas and larvae for up to a month; if fleas return, this product can safely be reapplied after a week (2 weeks for kittens). This product also kills chewing lice, but unlike its main competitor, Frontline Plus for Cats (*Est. $75 for a 6-month supply), it won't kill ticks.
Advantage II is applied at the nape of the cat's neck, where it's difficult for the cat to reach for grooming. Although most users find it easy to apply, some say their cats don't like the procedure. Most users find this product effective, but a few complain that it didn't work for their cats. We saw fewer reports of side effects in cats for Advantage II than we did for most other topical treatments; however, it is still more likely to cause problems than oral medications, such as Capstar for Dogs and Cats (*Est. $30 for six doses). Also, because this is a topical treatment, other animals or children can be exposed to the active ingredients. If this is a major concern for you, Capstar may be a better choice, but be aware that this product, used on its own, is only effective against adult fleas.
Advantage II for Cats is a relatively new product, so it has not received any recommendations from vets; that said, lots of cat owners have weighed in. Altogether, we found more than 450 reviews of Advantage II for Cats from pet owners at Amazon.com and Petco.com. An online pet pharmacy, 1800PetMeds.com, has more than 1,800 reviews for Advantage II, but the reviews cover both the dog and cat versions of the product. Information about the ingredients in Advantage II can be found at the Veterinary Partner website. In addition, articles at Dogster.com, Main Street Pet Care and the Feline Advisory Bureau attest to the safety and effectiveness of imidacloprid, the active ingredient found in both this product and the original
There are more than 1,800 user reviews of Advantage II at this online pet pharmacy, but they include reviews for both the dog and cat versions of the product. Overall, Advantage II earns 4.2 stars out of 5, with users granting it 4.2 stars for effectiveness and 4.6 stars for ease of use. These ratings are better than those for Frontline Plus, the other top-selling topical flea treatment.
Review: Advantage II, Contributors to 1800PetMeds.com
Altogether, Advantage II for Cats receives more than 150 user reviews at Amazon.com, spread across multiple pages -- including almost 90 here for the version for cats over 9 pounds. Most cat owners say they find this product effective, fast-working and easy to apply. We saw only a few complaints that it didn't work, and even fewer about negative side effects.
Review: Bayer Advantage II Purple 6-Month Flea Control for Cats 9+ lbs., Contributors to Amazon.com
We found more than 300 reviews of Advantage II for Cats at Petco.com. Its overall rating is 4.7 stars out of 5, and roughly 94 percent of users say they would recommend it. Several users say that this is the only flea product that has worked for them without causing harmful side effects.
Review: Advantage II Once-A-Month Cat & Kitten Topical Flea Treatment, Contributors to Petco.com
VeterinaryPartner.com is a resource for the veterinary industry. In this article, veterinarian Carol S. Foil compares the various flea control products on the market. Foil says the original version of Advantage for Cats kills fleas fast and maintains "100% killing" for at least two weeks. She also says that Nylar, the ingredient added to Advantage II, is "extremely effective against flea eggs."
Review: Flea Control, Carol S. Foil
5. Main Street Pet Care
The staff at Main Street Pet Care in Joplin, Mo., prefers oral flea remedies to topical treatments. However, they say that the original Advantage can be helpful for pets with flea allergies because it "rapidly kills most fleas before they bite the dog or cat."
Review: Flea and Tick Control, Staff of Main Street Pet Care
Although Dogster.com is a site devoted to dog care, this blog entry deals with flea treatments that can be used for both dogs and cats. Veterinarian Eric Barchas says that the original Advantage is one of several flea remedies that have "very low rates of adverse reactions," which are rarely severe; however, he does not evaluate the reformulated version.
Review: Eric Barchas, May 26, 2010
7. Feline Advisory Bureau
The Feline Advisory Bureau is a U.K.-based animal welfare organization dedicated to cats. The site recommends "spot-on treatments," including the original version of Advantage for Cats. These experts say that imidacloprid, the active ingredient, "has minimal effects on mammals."
Review: Tackling Fleas on Cats, Editors of Feline Advisory Bureau, Nov. 2008