My two favorite flea products are Comfortis® and Trifexis®. Both products are once monthly, chewable tablets. They contain an active ingredient against fleas, spinosad, and Trifexis also contains milbemycin which prevents heartworms and controls some important intestinal parasites (roundworms, hookworms, and whipworms). Fleas take a blood meal within minutes of jumping on a dog. In this way they are quickly killed by spinosad, a chemical that is much, much safer for mammals than for insects by virtue of differences in the nervous system.
We used to hear that “even one bite” could cause flea allergy. But, the number of mites DOES matter and Comfortis and Trifexis kill fleas more quickly than other products, minimizing the number of bites. They are not affected by getting wet or bathing in the same way that all topical products are, making them the best option for my patients that often require frequent bathing. Comfortis and Trifexis are prescription drugs that must be prescribed by your veterinarian. The choice between the products will depend on your pet’s specific needs and other parasite control prescriptions.