My cat got underdosed Frontline. Can I reapply safely for fleas?

It is safe to reapply the Frontline now, but in my experience, it doesn't have great flea protection. You may have better luck with Advantage products or a Seresto collar. The best flea protection is the prescription oral flea preventatives, like Bravecto or Nexgard.

It is labeled for use approximately every 4 weeks. If you need to use it more frequently, check with your veterinarian first. Most fleas live off the pet, necessitating the treatment of the environment as part of management. This includes vacuuming everywhere then disposing of the bag or emptying the canister outdoors immediately afterwards. Wash all bedding in the hottest water allowable. Use a cat safe area treatment to prevent reinfestation. A topical should be used for at least three consecutive months, preferably year round.

Since it's been two weeks since you late applied the Advantage, you can try another dose of it. He can also have Capstar again. Be sure to disinfect your home, as that will be a continuing source of fleas. Wash his bedding in hot soapy water, and vacuum the furniture and carpet surfaces. You can use a spray to kill fleas in the house, such as Indorex, or a flea bomb would work well to kill the fleas in the home. Best of luck, I hope this helps!

Hi and thank you for your question on Petco Pet Education Center, formerly Petcoach! Advantage II is not safe to use twice in 48 hours. The product safety specifications indicate that it should not be applied more often than once every 7 days for cats. I would not want to overload her system with more topical product in case she received a full dose and all of the dose was absorbed. In a week, it would be okay to apply another application. Hope this has helped!

The two treatments are not closely related but I would still recommend 7-10days before reapplying. You do not mention why you washed off the advantage but I would recommend combing with a flea comb to remove fleas in the meantime if still present. It may be worth considering using comfortis or capstar tablets if he does not tolerate spot on medications (it is often the carrier and not the active ingredient that pets are sensitive to)

Since both Sentry and Frontline use the same active ingredient (fipronil) it is unlikely that you will see better protection switching to the Frontline. You will need to choose a product with a different ingredient, like Advantage or Revolution or a Seresto collar. If you choose to use another topical, I would recommend bathing your kitty today to remove any remnants of the Sentry, and wait 3 days to apply the next topical. It is important to wait after bathing so that the natural body oils have time to coat the skin to ensure adequate absorption. You do not need to wait or bathe to use a Seresto collar.

Cats can be sensitive to flea medications. For that reason it is safest to wait 2 weeks between products even with different ingredients. Your vet can prescribe a cap star which is a pill that will last for a day that can help while you wait the remaining time