Charyl Williams asked 8 years ago
I have a very big cat, 25 lbs, and flea medicine is not working on her. Years, ago our Vet told us to use .8 ml of advantage for large dogs on our cats, and it worked perfectly for years. Now, that Vet has retired and we have a new one we don’t know very well. Then flea medicine seemed to not work the whole month, then it seemed to not work at all, so I tried Pet Armor and Frontline, but they are no better. So I bought a Sentry flea collar. Now she has fleas on her lower stomach, but not on her upper body. What should I do? Should I put flea drops lower on her back instead of high on her neck? She can’t reach it to lick it. Could I spray Advantage flea spray only on her lower stomach along with using neck flea drops? How do I get rid of the fleas? I also have 3 other normal size cats and it seems like the flea medicine works on them for about 3 weeks, not a whole month. Thank you for your help.
Adam Retzer Staff answered 8 years ago
Hello Charyl,
I’m sorry to hear about your flea problem. This sounds like an issue that would be best discussed with your veterinarian. I don’t have the credentials to offer expert advice on treatments, especially with off label uses. However, I will share what I’ve read.
First off, be very careful when using dog treatments on cats. Never use a product containing permethrin on cats. It’s highly toxic to cats, but not to dogs. Some flea products for dogs contain this ingredient (for example Advantix II).
Generally, it’s best not to keep switching between treatments, as it can lead to increased resistance. Also, it’s important to give a specific treatment time to work before ruling it out.
Flea drops for cats are formulated for different cat sizes. For example, Advantage comes in 3 different formulations, depending on cat weight. Ensure you’re using the correct product for your cats, which it sounds like you are. But, if not, it can affect efficacy and may be causing part of the problem.
I makes sense that the Sentry flea collar isn’t protecting the whole body, as the product isn’t made to translocate the treatment as well as flea drops.
Topically applied flea drops spread over a pet’s whole body in 24 hours in a process known as translocation. The active flea-killing ingredient (fipronil or imidacloprid) isn’t absorbed well through skin. Instead, it’s stored in the skin’s oil glands, and, as a result, it naturally gets dispersed and covers the animal’s skin and hair over the course of a day.
Spraying your cat’s stomach won’t be necessary. If the flea drops are applied properly on the neck, the treatment will translocate to the stomach within a day.
There hasn’t been any reported resistance of fleas to fipronil or imidacloprid. However, this doesn’t mean there aren’t isolated cases of diminished efficacy. It’s hard for me to assess your specific situation, with your one large cat not being protected and your other 3 cats not being protected for the full four weeks. Again, these are issues which are probably best discussed with your vet.
It’s important to remember that it can take up to 8 weeks or longer for fleas to be completely eradicated. The eggs, larvae, and pupae develop in carpets. Once they mature into adults, they jump onto animals. So, you will still see a few fleas here and there until the infestation completely ends. This is why it’s important to continue the monthly treatments for the advised duration on the labels.
The adulticide in flea drops (fipronil or imidacloprid) will kill the newly acquired fleas on your cats within a few hours. Flea drops also contain an insect growth regulator (IGR), either pyriproxyfen or (S)-methoprene. IGRs mimic natural insect hormones, and will prevent the females from laying viable eggs, even if the females survive long enough to feed and mate on a cat.
It may be beneficial to spray the carpets in your home with an IGR as well. Not only do these hormone mimics prevent adult females from laying eggs, but they will also stop larvae from maturing into adults. This puts a kink in the life cycle, and can help eliminate the fleas more rapidly.
Many flea premise sprays contain an IGR, again either pyriproxyfen (Nylar) or (s)-methoprene (Precor). However, most premise sprays also contain an adulticide, which some home-owners prefer not to spray in their homes. In this case, it can be a good idea to purchase concentrated IGR alone, as they’re considered safer than conventional insecticides.
Lastly, mechanical control is an important part of any flea control program. Vacuum carpeting and rugs at least every other day. Focus on flea hot-spots, which are areas where your cats frequently rest. Also, wash pet betting and small rugs at least once a week.
I hope this information was helpful and that your new vet can help. You seem to have a tricky situation with the one large cat.
I wish you the best!
Adam
