Topical flea control treatments are applied directly onto a dog's or cat's skin, usually between the shoulder blades or in several locations down the back for dogs, or at the base of the neck for cats. In most cases, the animal's natural body oils distribute the medication throughout its skin and hair; however, topical treatments may also be absorbed into the bloodstream through the skin, so that fleas ingest the insecticide when they bite. In general, topical treatments eliminate fleas within about a day and remain effective for about a month. Topical flea control treatments that contain pesticides must be registered with the Environmental Protection Agency (EPA) before being marketed to consumers to ensure that they are safe. (The Food and Drug Administration is responsible for regulating oral and injected medications.)
Topical flea control treatments are administered once a month and are usually sold in a multi-pack of three or more doses. All topical flea control treatments contain a pesticide that kills adult fleas, but their active ingredients vary. Some products also contain an insect growth regulator (IGR), which breaks the life cycle by preventing flea eggs from hatching and larvae from developing into adults. Additionally, some topical treatments contain chemicals that repel or kill ticks, heartworms, roundworms, mosquitoes and/or lice.
The safety of topical flea treatments is the subject of some debate, and some harmful side effects -- and in rare cases even deaths -- have been reported. Following an investigation, the EPA, in 2010, announced new standards to strengthen labeling requirements and develop stricter testing requirements for both new and existing products. Those standards require different brand names for dog and cat products and clearer instructions and dosage information to prevent misuse.
Despite these concerns, most veterinarians say that topical flea treatments are safe as long as they are used only as directed. For instance, it is extremely important that you do not use a dog product on a cat or vice versa. Additionally, consumers need to use the correct dosage for their pet's weight, as serious or life-threatening side effects can result from using a topical treatment that's too potent. Topical products also should not be used on puppies or kittens below the minimum allowable age, which ranges from 6 to 14 weeks depending on the pet and the product. Finally, although most topical treatments are available without a prescription, experts strongly recommend consulting a vet before administering them to a dog or cat --especially pets that are young, old, sick, pregnant, nursing, taking other medications or diagnosed with a skin condition.
The two most popular brands of topical flea control treatments are Advantage and Frontline. Veterinarian Eric Barchas at Dogster.com recommends both brands, saying they "have very low rates of adverse reactions, and when adverse reactions occur they rarely are serious." The U.K.-based Feline Advisory Bureau also recommends both Advantage and Frontline for treating fleas on cats. Both brands are available online without a prescription; however, the EPA cautions that some retailers may be selling counterfeit products, so buy from a reputable dealer or pet store.
Users are split over which of these two brands -- Advantage or Frontline -- is the best topical treatment for fleas. Advantage has been reformulated, and the new version, Advantage II, generally gets better reviews from cat owners. However, the new product has not received any reviews from veterinarians to back up these consumer opinions. Frontline Plus, by contrast, gets good reviews from both vets and owners, though feedback is more plentiful and more positive for its use with dogs. We also found some feedback for Revolution, and it, too, is available in formulations for dogs and cats. However that feedback is more limited, and Revolution is a little more expensive than either Frontline or Advantage topical flea treatments.
Frontline Plus comes in two versions, Frontline Plus for Dogs (*Est. $75 for a six-month supply) and Frontline Plus for Cats (*Est. $75 for a 6-month supply). Although it is somewhat more expensive than Advantage II, Frontline Plus does have one advantage over its competitor: its active ingredient, fipronil, kills ticks as well as fleas and lice. Frontline Plus also contains an insect growth regulator (IGR), S-methoprene, that kills flea eggs and larvae. Another Frontline product, Frontline Top Spot, does not contain the IGR and is slightly less expensive: Both Frontline Top Spot for Dogs & Puppies and Frontline Top Spot for Cats & Kittens cost about $70 for a six-month supply. Both Frontline products are safe to use on puppies and kittens at least 8 weeks old and are available in three-, six- or 12-dose packages.
The vets at Twin Maples Veterinary Hospital in West Carrollton, Ohio, recommend Frontline Plus, saying it is safe and effective for preventing fleas and for eliminating an existing infestation. Frontline Plus for Dogs is the top-rated flea control product in user reviews at Petco.com and Amazon.com, with most dog owners saying it works well and is a good value. However, a significant minority of users complain that Frontline Plus for Dogs is ineffective. Some say it never worked, and others say it stopped working after years of use. On the plus side, we saw very few reports of adverse reactions in dogs from this product.
Frontline Plus for Cats also receives mostly positive reviews at Petco.com, but its ratings at Amazon.com are mixed. Several users give Frontline Plus for Cats the lowest rating, mostly because they found it ineffective. At 1800PetMeds.com, reviews for Frontline Plus for Dogs and Frontline Plus for Cats are grouped together. Nearly 2,900 reviews have been posted here, but the overall rating is unimpressive. Satisfied pet owners say Frontline Plus has worked well for years, while disappointed pet owners say their pets still have fleas.
Some say that Frontline Plus worked well in the past but recently stopped working. We also saw a few reports of adverse reactions, mostly in cats. Hair loss and skin irritation at the application site are the most common problems, but more serious reactions may also occur, especially if the cat manages to lick the application site.
The patent for fipronil, the active ingredient in Frontline products, expired recently, opening up the market to generic products. Two examples are Sentry FiproGuard (*Est. $55 for a 6-month supply) and PetArmor Plus, sold exclusively at Walmart (*Est. $30 for a 3-month supply). However, veterinarian Lorie Huston reports in the Pet Health Care Gazette [http://www.pet-health-care-gazette.com/2011/05/14/best-flea-treatment-for-dogs-and-cats/] that while these products do contain the same active ingredient as Frontline products, they do not have the same "translocation technology that allows the product to be spread through the skin."
Merial, the maker of Frontline, says that technology is what makes its products effective. The few user reviews we found for Sentry FiproGuard at PetSmart.com and 1800PetMeds.com were unimpressive, with a majority of users saying the product didn't work -- including users who have previously had success with Frontline. The 150 or so reviews we found for PetArmor Plus at Walmart.com are also highly mixed, with only about half of all users recommending the product. Based on these reviews, it appears that these generic products should not be viewed as true equivalents to Frontline products.
Advantage II for Dogs (*Est. $60 for a 6-month supply) and Advantage II for Cats (*Est. $60 for a six-month supply) contain the active ingredient imidacloprid, which kills nearly all fleas on the pet within eight hours. In addition, Advantage II contains an insect growth regulator (IGR) called pyriproxyfen, which combines with imidacloprid to eliminate fleas at all stages of their life cycle. Advantage II is also effective on chewing lice, but unlike Frontline products, it doesn't kill ticks. Advantage II is waterproof and remains effective for up to one month. It is safe to use on puppies as young as 7 weeks and kittens as young as 8 weeks. Advantage II can be purchased in packages containing a four-, six- or 12-month supply.
Advantage II is one of the top-rated products at 1800PetMeds.com, where roughly 1,800 reviewers give it high overall marks for effectiveness and ease of use. Reviews at Petco.com and Amazon.com are generally positive as well, although there are not nearly as many of them. Owners generally agree that both the dog and cat versions of this product eliminate fleas quickly. However, as with Frontline Plus, a small but significant minority of users find this product ineffective. Some pet owners say Advantage II is not as effective as Frontline products, while others report that Advantage II worked where Frontline failed. A few complain that Advantage II is less effective than the original Advantage formula. We saw fewer complaints about side effects for Advantage II than we did for Frontline Plus.
Revolution for Dogs (*Est. $95 for a six-month supply) and Revolution for Cats (*Est. $90 for three-month supply, depending on cat's weight) cost more than other topical products, but both versions control a range of parasites in addition to killing fleas and their eggs. Revolution for Dogs controls heartworms, ear mites and sarcoptic mange (caused by a mite that lives in the pet's skin), and it kills the American dog tick. The cat version of the product controls heartworms, hookworms, roundworms and ear mites. Unlike Frontline and Advantage products, Revolution enters the pet's bloodstream through the skin and redistributes from there to the other tissues. One downside is that a prescription from a vet is required to purchase it online. Revolution is safe for puppies as young as 6 weeks and kittens as young as 8 weeks, but it should not be used in sick, weak or underweight animals.
The vets at Twin Maples Veterinary Center recommend Revolution, saying it is particularly effective for cats and kittens. The product also receives a high average rating from more than 1,000 pet owners at 1800PetMeds.com; they say it dries more quickly than other topical flea treatments and keeps fleas off pets. Some pet owners say they have been using Revolution for five years or more. However, some pet owners say their pets got fleas or heartworms while on Revolution and a few -- mostly cat owners -- report adverse reactions.