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.



41 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.

    Reply
  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!!!!!!!!

    Reply
  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.

    Reply
  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

    Reply
  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.

    Reply
  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!

    Reply
  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…

    Reply
  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?

    Reply
    • 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.

      Reply
  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.

    Reply
  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????

    Reply
  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.

    Reply
  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!

    Reply
  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.

    Reply
  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!

    Reply
  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.

    Reply
  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.

    Reply
  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….

    Reply
  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!

    Reply
  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.

    Reply
  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.

    Reply
  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!)

    Reply
  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.

    Reply
  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.

    Reply
  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).

    Reply
  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!!!!!

    Reply
  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

    Reply
  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.

    Reply
  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.

    Reply
  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

    Reply
  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

    Reply
  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!

    Reply
  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.

    Reply
    • 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.:(

      Reply
  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.

    Reply
    • 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?

      Reply
  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

    Reply
  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.

    Reply
  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.

    Reply
  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.

    Reply
  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.

    Reply
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