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Advantage Flea Control Side Effects

Advantage Flea Control Side Effects

Advantage side effects

Advantage Flea Control is a topical medication, that when administered monthly, protects both dogs and cats from fleas. However, while Advantage is one of the safer and most popular flea treatments, it is still composed of chemicals that can have negative side effects on your pet’s health if not administered correctly.

The most common side effect of Advantage is irritation. In some dogs and cats, it can cause the area of the skin on which the medication was applied to become red, slightly swollen, and itchy. Additionally, after application of the medicine, a pet’s fur may remain oily or give off a slightly medicinal odor. While these side effects may cause discomfort, they should disappear within a few days after application.

Additionally, in rare cases Advantage may cause a few changes in your pet’s behavior. There are scattered reports of pets becoming lethargic, losing appetite, or become hyperactive after application. However, in studies conducted on Advantage Flea Control, lethargy, loss of appetite, and hyperactivity were only evident in 0.8% of dogs tested. These side effects lasted anywhere from one to ten days in those animals tested.

Many of the side effects caused by Advantage Flea Control are due to wrongfully applying the medication. This flea treatment is only to be applied topically, and is not safe for consumption. When the treatment is consumed it can cause drooling, depression, weakness, muscle spasms, dilated pupils, and panting. This product may also cause irritation if it comes into contact with the eyes. However, thoroughly flushing the eyes after contact will be able to limit irritation and remove the product safely.

Properly Use Advantage Flea Control to Minimize Side Effects

Advantage is highly effective and rarely produces side effects if administered correctly. Pet owners should be sure to carefully follow the instructions that are included with the treatment while applying the medication to the animal. This includes only applying flea control treatments that are specifically designed for your pet’s species. For example, Advantage for cats should not be applied to dogs, as the reverse is also true.

As the instructions clearly state, Advantage is to be applied at the scruff of the neck, where an animal will not be able to lick or remove the treatment. In addition, this product is not to be applied to pets that are pregnant, sick, underweight, or under 7 weeks of age, as it may cause adverse reactions. However, when properly administered, Advantage Flea Control is a great treatment for keeping your pet flea free.

75 Responses to “Advantage Flea Control Side Effects”
  1. Sydney Kessell says:

    Every cat I’ve ever had (and that is 5 of them) has always gotten sick after I apply Advantage for Cats. It always passes without a crisis, but I make sure I only apply it when I can keep an eye on them and on a day the vet will be open, just in case. My cats don’t vomit. At least not inside the house where I have noticed. They are indoor/outdoor cats. But they act needy and want to be held or want to stay close to me (like they do when it thunders) then they will find a quiet place and sleep for a long time. After several hours and a good sleep they are always fine but I just know after 8 years of cat ownership and 14 years of dog ownership, my cats react differently to flea medicine that my dog did. Each time I give it to them, it makes them nauseous or something because their behavior changes. Every time. Every cat. It’s obviously a side effect that is very common.

    • Emmalee thomas says:

      Thanks bunches I just gave it to my nine year old female and she’s hiding ..but ur message helps so much to calm my nerves…

  2. Micael says:

    I have an 8 pound 2 year old Siamese. This is the second time that I have applies this product (Advantage II for small cats). I have never been so worried or scared for my pet since this application. Immediately after the application, he ran off and began running up and down the hallway. He would stop, mid-run, and begin biting his legs like he was being bitten by something. And for the first time since I have had this cat, he hissed! Not at me, not at anything, he just looked, his tongue slightly protruding and hissed at the air. His eyes have been more dilated than ususal, more like in the hunt/attack mode. He has spent the past two days in the dark under beds, which is totally unlike him. (Usually he is my shadow and right by my side, in my lap, on my shoulder.) We are going to the vet tomorrow. He has been standing in the middle of the hallway and letting out a catterwall or two and then going back in the dark. Also, playing “Mice under the blanket,” where he chases my hand under the blanket, has stopped. It is almost like he can’t focus on were the noise is coming from. He can hear it, but his eyes aren’t following the sound like he used to. I am petrified! MONITOR you pet constantly for at least 72 hours after applying this. I would hate to think that this product would be responsible for doing any permanent damage to my cat. but seeing that it works on the Cental Nervous System in Fleas, I guess it would be just as easy for it to attack the Central Nervous System of the cat. Never Again!!!!!!!!

  3. Tiffany says:

    I gave my indoor 6 month old 6lb cat the correct dosage the correct way 4 days ago. He is still very sleepy and is playing less. I have also noticed that he is kinda jumpy and his fur is getting oily as well. Looks like this is going to lead to even more more money spent at vet as if this stuff isnt expensive enough as it is… im very suprised theress not more info on net about these side effects considering last comment made. Needless to say i am not very happy about this experience.

  4. Adrienne says:

    I gave my 2 cats Advantage2 early this afternoon and they’ve been sleeping since…also their eyes are dilated. i hope their okay. im really worried about them

  5. Lisa says:

    I recently used Advantage on my 8 year old, 12 lb, Siamese mix. (We just adopted a friend for him from a local shelter and he must have brought the fleas home, since my guy has been an indoor cat).
    Unfortunately I placed it too far on his back and he was able to lick the medication. I almost had heart failure when I saw him foaming at the mouth, shaking his head, and trying to meow. I called the vet hospital and they said he would be fine, just wipe the remaining medication off where he could get to it.
    His appetite has remained fine, but the following days he threw up twice. Now, three days later, he just seems…tired…just not himself, a little more clingy than usual, and quiet. (He’s never quiet) :-)
    I’m calling my vet today to see if I should just keep an eye on him or bring him in.
    My new cat seems unphased by the experience and has suffered no effects.
    My vet is a really good, holistic oriented practitioner, so I trust that she wouldn’t have me put anything on my little guys that would hurt them.
    I’m just hoping he’ll be ok. We certainly don’t want him to suffer with the fleas, but I don’t want to use something that is going to make him sick either.

  6. Kari says:

    I properly used Advantage II on my 6 lb. yorkie/maltese 4yr old dog and he had a bad reaction every time. I tried using only 1/2 of the dose the following month and he still had the same reaction. He would chew at his legs and hind quarter obsessively and act neurotic. He was chewing himself raw. I had to give him a small dose of children’s benadryl to calm him and stop his itching. I will never use this product again!

    • Sam M says:

      Thats the exact same reaction my dog is having to this product. I have just given him some benedryl and will take him to the vet later if there is no improvement.

  7. Amy says:

    I have used this product on my cats for years, and for the past couple of years with my dog… I wanted to post that I have never had a problem. It seems worst case scenarios are only posting their feedback… However, because I don’t like the idea of chemicals, I only use this product as needed rather than on a monthly basis…

  8. Beatrice Kogan says:

    This is to report that the new cat reacted very negatively to Advantage.
    The skin between his shoulders the size of a 10p lost its fur and is irritated. He had diarrhea and saliva was frothing out of his mouth.
    He has not eaten as much since having Advantage 72 hours ago.
    He now looks upset and scared.
    I am not very impressed with the side effects.
    I ask myself what some animals had to go through when this product has been tested?

    • JC says:

      With cats you aren’t supposed to apply it between the shoulders. You are supposed to apply it a little higher up where they can’t lick.

  9. Marilyn says:

    I have a small, indoor 7 year old Siamese cat who has a seizure disorder. From previous experience, the Advantage can also trigger seizures. I will not use this product again, even at my vet’s suggestion.

  10. Heather says:

    I have an 8 pound Chihuahua and it has seemed to me that every time we give him his Advantage topical flea treatment, within 15 minutes he is mopey, lethargic and sleepy with no interest in anything. He is usually ok within a day or 2 but I’m started to get more and more worried that this is not the best method. The product works and I know these are not considered “usual” side effects, but just as with people medicine just because they don’t “usually” happen doesn’t’ mean they can’t happen. Is it possible to give half a dose? or would Advantage consider making smaller doses or even to be able to order specific weight and breed meds? That does sound like alot but these are our kids we are talking about and a sensitivity is still a reaction even if its not considered allergic. The big question is what else works out there????

  11. Vickie says:

    I used Advantage on my 5 year old Plott Hiund and with in 20 minutes she was running around nervously, drooling, whimpering, and pacing the house. She sleeps in our room and has NEVER acted like this. She begged to leave the too. And laid in the corner I went to her and found puddles of drool all over. He started hiding from me and acting confused. All out of character for her, so I jumped on the Internet! Read jut enough to immediately bathe her in dawn dish soap. I have used this product every month now for 2 months (it’s a 4 pack) . The bath helped but, she is still drooling some and very nervous. I called Advantage they said she would be fine, I sure hope she is! I think some better labeling is in order.

  12. Karen says:

    My chihuahua gets freaked out… he jumps up like he’s been shocked, he paces, and seems sensitive to touch. He scats around the house and gets very restless… I hate it!

    • Tammi W says:

      My chihuahuas both do the same thing! Not to mention they act like I’m a monster and won’t come to me either, I only use it once in a while when the natural shampoos and sprays don’t seem to phase the fleas.

      • Wanda Gonzales says:

        I have a 6lb chawahaw and she feels out, I hate watching her go though this. I hope tomorrow she will do better. She jumps for no reason .

  13. Leslie says:

    I have 4 cats 2 maincoones(inside/outdoor cats) and 2 bangles(indoor cats). I put the advantage on all 4 of them and everything seemed normal. However the next day one of my bangles slept all day all night and didn’t eat. My other 3 cats were normal with their sleep,eat and play. So i thought huh Cleo must be just really tired. On day 3 she still wouldn’t eat and still sleeping the whole day and night. Cleo is normally very social cat and gets into cute little stages durning the day when she will run around the house bouncing off the walls and furniture. She is just so playful and has a lot of energy . I called the vet they side it does sound like a side effect that maybe she was grooming her sister and ingested it.They she should feel better in a few days. They said if it lasts more than 10 days give them a call. This is day 6 and she coming around a little.

  14. Jessie says:

    I gave my dog the small dog flea medicine, she acts sad and scared after it is applied. She will run and hide. This is the second time she has acted scared after it is applied. When I tried to put it on her the next month she wouldn’t come to me even with the temptation of treats! She is a min pin so she loves her treats. wont be using this again!

  15. Par Redfern-Laprade says:

    Advantage2 does not seem to be as effective as the original Advantage on our cats They also were crazy after applying it for the first time this year. They should discontinue this Advantage2 and go back to the original Advantage which was great! Are “biting lice” really a problem? Not here.

  16. Heather says:

    I applied Advantage II to both my large cats yesterday for a flea flareup and within 2 hours they were both down for the count. They have been lying about all day and all evening, stretched out and not even in their normal spots. And believe me, my boys are creatures of habit. I’m sure it’s a combination of being bitten up, being combed and literally nit-picked then being doused with chemicals, but it is worrisome to watch my 2 little fighters look so out of it and depressed.

  17. R Sammone says:

    My poor Westie…. after using Advantage (not II) for years.. (Frontline did not work for him at all), I applied II and OMG…. He had a HORRIBLE reaction… He went crazy…panting, running in circles–totally freaking out…I called the company (BAYER) and was told to bathe him 2-3 with dishsoap, to try to remove the product..This is the second day now..and he is having trouble with his hips, choking/coughing after eating/drinking, shaking… The person from BAYER said it is something akin to having your foot go to sleep…(after telling me it couldn’t be the product)… Maybe this is something specific to West Highland terriers..dk.. but …. I am worried.. anything like this happen to anyone??? HELP….

    • Sam M says:

      My dog is having the same reaction and he is not a Westie. No problem last year with regular Advantage but the Advantage II is having a horrible effect on him. I do not recommend this product!

  18. D says:

    Do not use this product. I have done extended research on this and while my cats are in the hospital for a week now with seizures due to one application applied between two cats. There have been reported thousands of cases on this product with severe consequences. Do your research! I don’t ever want another pet owner to go through what I am going through. As of right now their care is ongoing and I pray to God Advantage Flea and Tick Repellant will help me and do the right thing!

  19. love my cats says:

    I applied the advantage on my brother’s cats yesterday and almost instantly they started frothing at the mouth and salivating and also vomiting. I was horrified!!! Then one of them hid somewhere and the other one was running around like frightened by something. I have my own three cats and I’ve used Advantage,Pet armor,Frontline,Revolution and I’ve never had any problems. So this was the first time I’ve experienced this.It was really scary!! I called my brother today and he said the cats are fine. Thank goodness! I was feeling so bad.

  20. Laura says:

    I just gave this medication to my two cats. Both of them were able to lick their fur where I applied it,which was between the shoulderblades, and ingested some. My younger cat is acting fine but the older one began running around franticly and foaming at the mouth. I tried to pick her up from off a small side table thinking she was having a seizure but she resisted me and ran under the bed. From there she seemed to be really confused and dazed. She did come out for a short while to eat and seemed more like her friendly self but she’s still not quite right. Honestly, I would never buy this product again or recommend it to anyone. The best thing I’ve come across for fleas is dawn dish soap, though it can dry out the skin a little bit, it kills the fleas instead of shooing them onto your carpet.

  21. Pug Lover says:

    Some veterinary professionals may not support this information but it is TRUE: I have used Advantage on two occasions when I found adult fleas on my dogs. (Yes, I applied it properly.) Both times, approximately 24 hours after using Advantage, two of my three dogs (not related but same breed) had very strong “burnt” smelling urine and their coats also give off this same odour. This strong smell lessened after about a week. The dogs showed no negative signs other than this “stink.” (No, I am not imagining it!)

    • Charm says:

      Yes! I applied the advantage last night and now my chihuahua smells horrible. I looked everywhere to see if he went potty on the floor before I noticed it was him! Even my shirt smells now.

    • KoriB says:

      My vet applied this product to our new puppy, and she also has a nauseating burnt-cherry sweet smell. I have bathed her twice now and can’t get the smell off. I’m literally going to be sick with the smell of her. No other negatives signs.

    • Pom Mom says:

      The 1st time I applied this product to my 7lb Pomeranian I noticed his urine smelt very strange and produced a very strong aroma. It is such an odd smell and hard to describe. I thought he had a bladder infection the 1st time it happened and spent over $200 to put him on an antibiotic and be told there was no infection. I was told if the smell came back he may have bladder stones again that would require an x-ray to see the stones and be removed surgically for the 2nd time. I put the product on him yesterday and as soon as he went to the bathroom outside this morning I could smell it. I came home from work and my entire house smelt like this horrible burnt urine smell. Then I started thinking maybe it was related to putting this product on him, so I googled it and found your post. So thank you, I don’t feel so crazy and will save 100’s of dollars from having to take him back to the vet. I am going to bathe him right now in Dawn dish soap and just hope the God awful smell goes away. Thank you!!!

    • Hb says:

      Im having the same problem with my Aussie I wonder if it’s the kidneys unable to process this stuff.

  22. denise says:

    i applied advantage II to my 7 year old female cock-a-poo and she started having really bad reactions, shaking, nervousness, irritation, I was so freaked out I called the emergency number on the box. They advised me to wash the area very well with DAWN dish liquid. it’s too strong for sensitive skinned dogs.

  23. Anonymous says:

    My year old Papillon became completely lethargic after giving him Advantage 2. He was sleeping all night and day, wouldn’t eat, and I had to carry him out to use the bathroom, he later urinated on himself. I called my vet to make an appt. Meanwhile I searched online to see if there were any other reports of reactions. After reading other people’s accounts and some advice to bathe the pet to remove the remaining toxin from the skin, I did so, and he perked up almost immediately! I’m still having him checked at the vet, but he’s fine now, and the vet even said I should call the company. When I called, they were very demeaning, letting me know that these symptoms couldn’t come from the med, but they’d put in a report. I wasn’t asking for money or anything, just calling to report it.

  24. Don says:

    Earlier today I applied Advantage to the back of my cat’s neck. Observations since the application: My cat tries to scratch the area with her hind leg (I would expect this), is even more fidgity and scratchy on other parts of her body than she was with the fleas. She takes steps very carefully and halfway down tries to take a different route than usual. She seems confused generally. She seems extra agitated. She seems extra distracted by things she isn’t normally interested in. She made a miscalculated jump (which she never does). All in all, her behaviour is different and she seems to be experiencing something that is confusing for her. She also seems to want to eat a lot, and wants her “special food” (salmon) I expect because she has a funny taste in her mouth that she wants to mask. While the makers of Advantage and my vet may both claim that this is nontoxic to cats, it’s definitely having an effect on her that is perceptible. Concerned but not worried (yet).

  25. Melody says:

    Gave my dog Advantage Flea control on Thursday night by Friday not eating vomitting, lethargic, drinking lots of water sometimes is able to keep it down sometimes not. Called the company and they do not believe this is a reaction to this flea control medication. Needless to say I will not use it again!!!!!

  26. diane says:

    I used advantage for dogs on my 1 year old dog yesterday ,i used the correct dose ,placed it on the scruff of her neck where she cannot reach within 2 hours of giving it to her my normal dog who loves cuddles and could sleep the clock around has raced around the house ,refused to be cuddled ,stood in the garden but just gazed into space and not slept in over 24 hours I`m terrified she`s been bathed at 2am this morning thinking it may wash out some of the product I rang the vets but got told it was not a side affect of this product but after reading reviews it is it could last upto 10 days so I am going to give her a second bath and fingers crossed it may wash off a bit .Please be warned ADVANTAGE DOES CAUSE HYPERACTIVITY IN DOGS !please please let it just be hyperactivity and nothing else my gracie is my baby

  27. dianna says:

    Never again will I use this product. My cat did the same as the one above. It ran screaming for hours around the house like it was confused. It was running under beds, hissing and bitting its legs. I sure it was a bad reaction. I hope it hasn’t caused some Neurological dysfunction. The cat is always gentle but it acted like it was mentally out of it.

  28. Pat says:

    We used this on our 11 week old puppy, and he was very sleepy for 24 hours. He lost his appetite for longer than that. He also seems to have spurts where he gets really aggetated, and wants bite alot. He wasn’t like that before. The box said you could put on 8 weeks or older.

  29. Kendra says:

    I applied this to my puppy, she is 4 months old, around 3 pounds. She acted like the Tazmanian Devil ALL NIGHT. There was no sleep in my household..biting, growling, aggresive “play”…for hours and hours..I finally had to go to work, so I have no idea if she ever stopped but normally if she is “playful”, it lasts an hour and she is exhausted and sleeping just like a baby. She also made less attempt at hitting the litter box…litterally just stuck one leg in,,and pee’d on the floor. She has been litter box trained for 2 months…very weird. I will never give this to her again

  30. Kelly says:

    My cat is 9 yrs old and I have been using advantage for 2 months on her, she has broke out on her tummy and sides , parts of her back and around her tail. I’m wondering if it’s from the advantage or something else. I’m hoping it’s something else because I love the advantage it works really well she has no more flees thank you, kelly

  31. mariann says:

    My 130lb lab mix is pacing, drooling , acting hyper…He wants to be outside rt now, its
    1am! I already washed it off of him…and I recommend to give half doses from here on out!

  32. HOLLY says:

    Up until now natural flea remedies have worked for my two Bichons. When they stopped working I had to try the chemical route. Shortly after the second application of Advantage 2 my 14 year old showed increasing signs of neurolgical impairment. He would go outside in the freezing cold weather and not remember he could come in. When I went to get him he would run the other way and act frightened. He started ocasional shivering while he was inside wearing a “t” shirt. Then he started shivering without stopping and even when sleeping. He seemed to be doing things by wrote and not able to think anymore. His brain was out to lunch. Luckily I work in alternative healthcare and had a special test done. There was neuraogical impairment that was treatable with an energy patch that miraculousley turned the problem around in a mattter of hours. Although I can’t prove it was the flea treatment, you can be I won’t ever do it again. He is back to normal now and back to natural remedies.

    • Michael says:

      I gave my 18 yo cat her dose on the back of the neck and next day she seemed out of it, wanting to eat she couldn’t open hew jaw, her tongue was protruding a bit, she couldn’t drink,not interested in getting out of bed either, I was worried and took her to the Vet, he said looks like a seizure, gave her Cortisone and put her on a drip, 3 days later no improvement, the Vet suggested she was old and we decided to put her to sleep..:(..now reading all these experiences people have had with this product, I am wondering if I took the wrong course for my dear Ninja.:(

      • AK says:

        your vet said she was “old” and allowed you to agree to PTS?…GET ANOTHER VET ASAP!

  33. Greg says:

    I began Flea control on my 9 month old kitten in January 2013, after the third monthly treatment in March he experienced serious neurological issues, he could no longer walk or hold his bowels, we thought he would die.
    Our regular vet ran full Blood, Urine and x-ray, all normal and healthy, we then sought out a specialist. He ran another bunch of tests…again all negative.
    He prescribed appitite stimulant and l-carnitine.
    Our Kitten celebrated his 1 year birthday and has not only gained some weight back he hasn’t regained it all. He is better about using the box but isn’t completely there yet.
    He is Slowly getting better, I hope he has a full recovery, he is still very slow and doesn’t jump or play as he did as a kitten the first 9 months.
    I will be using Neem Oil in the future for flea control.

    • Theresa says:

      I’m glad to hear that he’s doing better and I’s sorry that you had the go through that. Did they say what caused it after taking it for that long?

      • Greg says:

        I was never given a reason. Bayer takes no responsibility for testing their product.
        the same cat today is better but infested with fleas and Dawn Bath’s and spraying with evolve, a cedar lemon oil is torment for him. I never did get the neem oil.

        I’m hoping that tomorrow’s vet visit for weight loss is just due to worms, his appetite is just fine.

        I would be willing to pay for a blood test to determine if there will be any allergic reaction however Bayer and other treatments will not provide any information even to my vet.

  34. Leo Deoni says:

    i gave Advantage multi 55 to my 13 year old border collie cross (Gracie) and she seemed to have only a little lethargy however, the same product applied to my 8 year old american eskimo (Chimo) made him very anxious, drooling, fearful and he vomitted within 5 hours. the following day he was still irritated trying to roll on his back in the grass to remove some discomfort. Chimo has sensitive skin and can experience sunburn on his pinkish nose so i suspect the difference between Gracie and Chimo is simply sensitivity as Gracie in contrast some years ago received a suture next to her eye without a local and barly flinched. she rarely complains about discomfort and i always know when something is bothering Chimo! both dogs are in excellent health and get lots of exercise and homemade food but i would be very concerned about the extreem stress this chemical creates if that was not the case… i am looking for alternatives because its hurts my heart to see Chimo’s reaction. hope this info is helpful

  35. JC says:

    I’ve used Advantage on all of my cats in the past and never had a problem.

    About a week or two ago, I applied some Advantage II to the base of my cat’s head, high enough so he couldn’t lick it.

    A minute or so later, he attempted to scratch the area with his hind foot a few times, I thought because he could feel the liquid trickling a bit, but I stopped him and kept an eye on him until it dried. It was all pretty uneventful, but today as I was combing him I noticed the area where I initially applied it had scabbed over.

    I imagine he might have some sensitivity to this newer formula that gave him a chemical burn. Has anyone else had this problem?

    By the way, if your cat salivates after you apply this stuff, it’s probably because you applied it too low, or it ran down, and the cat managed to get some in it’s mouth. It tastes extremely bitter and this is why they will salivate and froth if they get some in their mouths. This happened to my cat when he was three. Some ran down on to his shoulder and he licked it, then went running around the backyard like he had rabies. My brother and I finally caught him and managed to rinse his mouth a little and he was fine.

  36. coco says:

    I put Advantage II on my 13 year old Shepherd/Wrot (applied correctly). By the next day he had developed a horrible smell almost like old urine. I could even smell it on his breath. This cannot be healthy for him. I noticed it the last time I used it but this time was worse. I won’t use it again.

  37. CW says:

    I used Advantage II on my male cat for the first time and he now has a bald spot the size of a dime where I applied it….it didn’t happened immediately and I have been trying to figured out where this came from.. He is an indoor cat and I can only think after reading further about this product, that this is the cause. How long before the loss of fur happens normally.

  38. Judy says:

    I have used Advantage II for our three cats three times now and the only thing I see is our one cat does get lethargic. The topical does get oily. It doesn’t matter where I put the topical, on the scruff of the neck or the back of the base of the head. Our cats still scratch it off and lick their paws. So far the Advantage is working and periodically I will flea comb them for extra assurance.

    • Bobbie Lusch says:

      Same happened to my dog he started shaking, drooling, gagging, and then his back legs got weak and even became semi paralyzed bad enough that i have hadto lift his back and suppirt him while he tries to walk. At first when it happened it was put off by the vet as old age and hip dysplasia. But then the next time it was supposed to be something he ate like a mushroom or something like that.

  39. Bobbie Lusch says:

    But this last time after i applied his drops all the same things happened but this time he spent two and a half weeks unable to walk and i realky thought i was going to loose him. It was obvious that he was suffering some kind of neurological damage. It has now been fifty six days and he is starting to get around much better but his back legs are still weak and unstable. I can say i will never use Frontline or anything on him again.

  40. Linda says:

    My best friend is now 10 years old but when I rescued him as a kitten from a neglectful owner, he was INFESTED with fleas. Making matters worse, he was too young for advantage by 9-10 days so I had to watch him suffer for over a week before I could use it. When I could finally give it to him I read the directions and followed them to the letter…it killed me to have to refrain from petting him! By this time the fleas had taken over the house. I remember my husband getting out of the shower, sitting on the couch and within 15 minutes he had dozens all over his legs. I had visions of needing professional carpet cleaning and never ending laundry while I washed the fleas out of our linens, etc. Before applying, I did call my vet to ask about the fleas in the rugs, etc. Always the professional, my vet (Dr. Christine Stortz, Cape Canaveral, Fl.) explained that the treatment will actually kill the rug fleas also. I found this hard to believe but applied Advantage as directed. My buddy freaked out a little at first at the strange new feeling at the back of his skull and promptly hid under the couch for about 1/2 hour. When he came out, he seemed lethargic but wanted to sit on my lap as he had done every day since I got him. I knew I couldn’t pet him and I was curious as to weather or not I could actually “see” the treatment take effect so I put a white towel on my lap before he sat down. Now it was my turn to freak out, I actually watched hundreds of those nasty, kitten-biting little bastards jump off my little guy on to the towel to die what I hope was an agonizing death. There were so many fleas that I changed the towel THREE TIMES, cursing his previous owner each time for being such an irresponsible jerk. He didn’t have any appetite so he skipped his dinner and slept thru the night. Each time he got up to use his litter box he seemed lazy and lethargic and if didn’t know better, I would have sworn someone slipped a valium into his Fancy Feast. The next morning though, he was back to being his bouncy, happy little self and I couldn’t find one flea in the whole house. I spent some time vacuuming, (in my mind I could see millions of tiny, gross carcasses all over my house) but never a flea. As the vet explained to me, the kittens movement spread the treatment down his body and thru the house…I don’t understand it and I don’t care, I just know that for us, it was incredibly successful and I couldn’t have been more pleased with this product. I’ve used it ever since and each time the main side effect has been the lethargy. When he was younger, he would run a couple laps around the house immediately after applying and THEN take his nap, but now that he’s older, he doesn’t even budge when I put it on him, as was the case today. I admit to reminiscing about his “kitten days” though and thought about changing that towel 3 times and I tried it again today, 10 years later. I slipped a white pillow case under him before he lied down and sure enough, 20 minutes later 11 of the little A*@holes took their last bite, coughed their last cough and jumped off my buddy. To say that I’m a loyal and incredibly satisfied customer would be putting it lightly and I only wish the same for all cat owners.

  41. rachel says:

    I used advantage for the first time 2 weeks ago id used front line about 2 months before and the fleas stayed although they are no longer on the cat in the last week he seems to have gotten weaker his gone off his food and is very sleepy and weak on his legs after reading these commemts it seems likely the treatments to blame I will be consulting ba vet tomorrow

  42. Rita says:

    I used the spray for cats on my two indoor females. My 1 year old tortie seemed a little sluggish but overy all she is fine…on the other hand my 6 year old kitty started frothing from the mouth after, and had increased urination.She also started throwing up repeatedly and can’t eat alot. I applied correctly, just beware this product. Not a fan, my kitty does not need to be tortured to kill fleas. I gave her a bath and got all the product off so she seems to be okay now, but it really scared me. Just be wary giving this to older cats I suggest.

  43. roseyscats says:

    after reading these post I am scared for my kitten and 14 year old cat. I applied the medication correctly but am worried they may suffer some of the side effects listed above. any positive feed back on this product?

  44. Roni says:

    I applied the Advantage II to my one year old cat. The first day everything was fine. My cat remained playful and ate his dinner. The next day I hear him crying very strangely and helpless like. He was hiding under a dresser in the dark. His pupils dilated and he looks confused and seems not to know who I am. He won’t eat and remains hiding. I pray he is ok. This is the sweetest cat. I will never use this product on my pets again.

  45. Isabella says:

    I need help and can’t afford a vet. I have a 15 yr old cat and she is plagued by fleas. When I lived alone with just her, I could randomly apply Advantage as needed and she would be fine, the fleas would go and there we are. Recently I had to move into a house with 2 other cats. I put Advantage on my cat and two weeks later, she’s biting, scratching, and tearing her fur off (she can’t bear fleas at all). I waited a week and reapplied Advantage but it was like giving her flea food because she has not stopped biting and chewing at herself. I only just gave her Advantage a week and a half ago this past go but tonight I put another tube on her because she has just been plagued with them. By the way, the other 2 cats got doses just over a week ago, they’re fine. She is still sitting on a table now, biting, chewing, pulling out tufts of fur!!! I don’t know what to do. I’ve used Advantage on her for years with good results but my poor girl is going bonkers for the past 2 months with fleas. Can anyone tell me what to do? I can’t put anymore on her for at least 2 weeks, but why should I if it isn’t helping? I am heartbroken for my poor cat. She had to stay with these same people in a different house nearly 10 yrs ago for nearly a year and in that time she lost nearly all her fur to fleas because they didn’t know what to do and I couldn’t have her where I was living. I nearly lost her. I am sincerely scared and need good, sound advice. Please? thank you

    • margaret says:

      I would give her a bath using good old DAWN dish detergent. It is mild and kills fleas on contact(my vet uses it rather than flea shampoo as it is milder on the cats skin). Also get some flea killing spray and treat all the furniture, rugs, cat beds, anything fabric in the house to kill any fleas hiding there, too.

  46. margaret says:

    I have used Advantage for years on my cats with NO issue. This year I got some new kittens to keep me company as all my older cats had died in the last 2 years. Saturday was the first time I noticed them scratching, because the little orange boy kitten thinks he should be allowed outside (little stinker). I applied advantage to all 4 kittens (ages 1-1/2 years old and 6 months old). Within minutes all 4 were sneezing non-stop. Their appetites do not seem effected and their water bowls were almost empty this morning, but the sneezing hasn’t stopped (2 days later).
    Has anyone else ever had this issue with their cats and advantage?

  47. Michelle says:

    Just treated my dog with advantage and she started acting odd. She’s panting, pacing, and seeming off. She keeps coming to me to go out but not doing anything and just walking around the yard very slowly. She has had it before but this will be the last time. I washed off what I could but it’s been more than half an hour so figure it’s absorbed by now. Keeping an eye on her now, fingers crossed she will be fine. Too many negative stories regarding this to keep using it :(

  48. Carrie says:

    We just applied Advantage to our year old cat two days ago. He was very sleepy and out of it the first day. Today, he was foaming at the mouth and running around like he was possessed. He I has been sleeping for hours. I am reading all the other entries and want to know how long the side effects are lasting? I am very worried and will be calling the vet to find out what to do.

  49. Mrs Andrews says:

    I have 2 cats and last month when I used advantage the smallest suddenly got skittish and was running around like something possessed, while the older bigger one just took it in his stride. Within hours they has licked it off each others backs of necks where applied, but apart from a little disgust there was no visible harm done. I have again applied it to them, and again the older cat while not amused at the indignity of it, has again curled back up to sleep, the smaller younger cat is now crazily running around trying to escape the house, cowering when I approach her before running away. I have them separated for the past few hours to prevent the mutual grooming, but the little one is still going mental. Just goes to prove that it affects different animals separately I guess. Hopefully as before there is no harm done and they remain flea free for a few more weeks.

  50. garrett philipp says:

    My cat can get sick after Advantage II applied. I used a large cat size, but he IS a large cat (16+ lbs). He trows up and doesn’t eat for 2 days, then is OK. He might be able to lick it although I don’t think directly (might use his paws?). He is the kind of cat that has a sensitive stomach as he has had vomiting problems when he was little. Kinda scary, but fleas are worse (kind of, I hate to see him throw up and not eat). There is definitely a problem here with this flea met in my mind.

  51. Josh P says:

    I applied Advantage II to my 80lb American Eskimo/ Australian Cattle dog mix. He immediately lost his appetite. Then vomited the next day and shortly after that he was skiddish, hiding in closets and acting very timid. That night and the next day along with the following night excessive saliva and tremors. A rash of hives have broken out on his back and tremors persist, coupled with lack of appetite and lathargy now 5 days later. I’ve used this for 5 years on him accurately with no side effects in the past. Never again, this stuff is toxic.

  52. Steve R says:

    I wish I had known about and read all this before I put it on. He was rolling over the floor, I correctly applied it,salivating but not thirsty and been very listless, lying there snoring heavily. He is a Chiranian, weighs just under 4Kg so the meets the requirements for this “medication”. Before I had read this I had already decided to give him a full bath, shampoo and then rinse him thoroughly before giving him a full dry. Now I have read this and wish I had don’t it 5 hours ago immediately after dosing him, the other 3 in the pack will now go into my sharps box and in future I will use frontline as I used to do with my other animals. I am now going to have to keep a close watch on him overnight, he sleeps on my bed anyway and the decide if I need to take him to the vet, but reading this it appears there is no antidote to whatever has caused this reaction. I will investigate the active ingredient in detail and then the other mentioned “filler”, I will post back here later.

  53. kmcastro23 says:

    I’m so glad I found this site. I gave my two 9 year old cats Advantage II yesterday. One is fine, but the other is not. She was fine last night, but I noticed she didn’t get up to eat this morning. When, I went to check on her she was lethargic and her legs seemed weak. She was also flicking her tail like she was very irritated. After reading some things on other sites, I gave her a bath and washed the residue from the meds off. She is still on my bed and won’t eat or move much. She still seems irritated. I’m glad I’m not the only one who has experienced this. I’m hoping she will be better tomorrow, but I will keep watch on her and take her to the vet on Monday if need be. There is a vet in town that works on Sundays, so if she seems worse tomorrow, I will take her. Thanks to all of you who have posted. I did get some peace-of-mind by reading your posts, but am still worried about my baby.

  54. Stephen says:

    You would think Advantage would reply to the huge amount of responses showing that the product has quite severe side effects and they are NOT that uncommon.
    My cat had Advantage 1 week ago, his appetite dropped off and has now pretty much stopped. I’d rather he had kept the fleas and been happy as before.

  55. Tanya says:

    After treating my beloved Teddy Bear with Advantage II, he immediately started scratching, within two days he had a sore which is now the size of a silver dollar, it has also abscessed but burst and is draining out of the hole! He has lost so much weight and it was within two weeks. He is still very weak, I’ve made him his own food which spiked his appetite again, thank goodness, I will NEVER use this horrible product again! Not to mention it DOES NOT LAST FOR 30 Days! it’s more like two weeks. what ever Bayer did to this product is causing so mush anguish to pet owners with no consequences, We end up paying huge Vet bills to save our beloved pets. Bayer NEEDS AND SHOULD BE HELD ACCOUNTABLE! The emotional stress we have/are going through this a crime in itself! I

  56. Angela says:

    I read the first several reviews and am sad to report that I have joined the group of cat owners where Advantage had a negative reaction (to my male cat, contact burn). I must say though that we had used Advantage on my cats for several, several years without any problems, I loved Advantage. They only got mopey for a day and I think it was mostly because they did not want anything wet on their back. So recently with the contact burn on my male cat, he was still only mopey after a day and I kept a close eye on the contact burn (very, very red skin) and I’m not sure if he even knew it was there because he did not scratch at it and did not seem in pain. I was a very happy Advantage customer for several years until this year.

  57. Sue says:

    Advantage…. horrendous stuff!!!
    Just treated my 10yr old dog and he hasn’t stopped chewing his tail! It’s so bad that the underside has no fur and sore spots where he has been chewing.
    After reading the comments on here, I am sure he has an allergic reaction.
    Never again!

  58. Bill says:

    Makes my dog stink terribly. He’s vomiting as well. Never using it again.

  59. Chris says:

    My cat absolutely honks after applying this. He smells like he has singed fur. I actually got out of bed to look out the window to look for the fire! Then I found out he had peed on my pillows which is something he has never done!!! Cancelled my order.

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