Advantage Flea Medication Allergy in Cats
Written By hannah hollinger
Published: 03/26/2017Updated: 10/28/2021
Veterinary reviewed by Michele K.
Advantage Flea Medication Allergy in Cats - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
What is Advantage Flea Medication Allergy?
Advantage flea treatment is made by the company Bayer, and its active ingredient is imidacloprid. Imidacloprid is an effective and typically safe-to-use insecticide that kills fleas. Although it is considered safe to use, this active ingredient can cause adverse reactions by cats. 
This monthly treatment should not be used on cats younger than 8 weeks of age and should only be used by carefully following the instructions. It is to be applied between the shoulder blades of the back and you should only use the specific dosage according to your cat’s weight. 
The ingredient, imidacloprid, affects the nervous system of the fleas and paralyzes them. The fleas eventually die within twelve hours. Within just five minutes of applying Advantage, the fleas stop biting and the larvae are killed. This water resistant treatment lasts for about one month, and then needs to be reapplied. 
Many cat owners use Advantage flea medication because it is considered safe and effective. Other benefits of this medication are it is inexpensive, easy to use, and readily available in many stores.
Advantage flea medication is commonly used to rid cats of fleas and is considered safe. However, some cats develop an allergy to the medication, and if this occurs, it is important to contact your veterinarian.
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Symptoms of Advantage Flea Medication Allergy in Cats
If your cat licks any of the product or has an adverse reaction to the skin, he may exhibit the following symptoms. Symptoms of Advantage flea treatment allergy in cats include:
  • Drooling
  • Vomiting
  • Diarrhea
  • Irritation of the skin
  • Shaking of the head
  • Seizures
  • Loss of appetite
  • Lethargy
  • Difficulty breathing
  • Itching
  • Biting at the skin
Types
There are many types of safe flea treatments available on the market today; however they can still cause a reaction if not used properly or if your cat is allergic. Other types of active ingredients in flea medications include:
  • Selamectin
  • Fipronil
  • Methoprene
Causes of Advantage Flea Medication Allergy in Cats
Advantage flea treatment is generally considered to be safe for cats; however, some cats may develop a reaction to the active ingredient. Causes of a reaction include:
  • The medication is absorbed through the skin
  • The medication can enter the cat’s bloodstream
  • The active ingredient can cause nerve damage
  • The cat may suffer from an accidental overdose
Diagnosis of Advantage Flea Medication Allergy in Cats
If you suspect that your cat is having a reaction to his Advantage flea medication, contact your veterinarian. Take the container and packaging to the appointment with you so your veterinarian can be sure of what is giving your cat problems. Your veterinarian will ask you questions about the type of medication he is on to help fight his fleas. He will then take a closer look at his symptoms and gather information about them, such as when they began and the severity. 
The veterinarian may thoroughly wash and rinse your cat to remove any of the treatment and begin giving him fluids to help with hydration and to stabilize his symptoms. He may take blood work, urinalysis, and a biochemistry profile. The blood testing will focus on your feline’s serum levels. Although blood testing and urine testing are not always absolute, your veterinarian will be able to rule out other illnesses by taking a close look at your cat’s symptoms and having the knowledge that he began having a reaction after the application of the product.
Treatment of Advantage Flea Medication Allergy in Cats
Unfortunately, there is no treatment for imidacloprid toxicity, we can only provide supportive care for the complications. Your veterinarian will explain to you what you can do at home, and will treat his symptoms. Treatment methods may include:
Decontamination
Your veterinarian may have already washed and thoroughly rinsed your cat to help rid his skin and fur of the toxic ingredient.
Avoid Exposure
Your veterinarian will suggest to you that you avoid all further applications of the medication. He may also suggest holistic methods to help control and get rid of fleas.
Gastric Lavage
For severe cases of poisoning, such as if your cat has ingested the medication, your veterinarian may perform gastric lavage to help rid his stomach contents of the medication. This treatment method will be followed up with a dosage of activated charcoal and possibly a dosage of laxatives.
Fluids
Your veterinarian may want to keep your cat for a day or two and monitor his progress as he is on IV fluids. The fluids will help your cat remain hydrated and help further flush out any toxins.
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Recovery of Advantage Flea Medication Allergy in Cats
Most cats have an allergic reaction if they were given too much of the product or if they ingested a specific amount of the medication. Your veterinarian will communicate with you about your cat’s prognosis. Once you take your cat home, continue to monitor him for any other side effects or reactions. Be sure to give him plenty of fresh water during the day and night and monitor his drinking and urination habits. 
In order to avoid this from occurring again, you may want to consider other preventions to help control fleas. You can talk to your veterinarian about the types that are available to help your cat during peak flea seasons. If you have any questions about the main ingredients of products that can be used to help fight fleas, ask your veterinarian.
Advantage Flea Medication Allergy Questions and Advice from Veterinary Professionals
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American Shorthair
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Skittles
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4 Years
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2 found this helpful

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2 found this helpful

My pet has the following symptoms:
Swollen Face And
I applied Advantage to my cat a couple of hours ago and his face is now swelled up. Is there anything I can do to reduce the swelling? He doesn't appear to have any other issues.
July 25, 2018
2 Recommendations
You could try to give Skittles 5mg of cetirizine (if he isn’t on any other medication) to see if that would help with the swelling, but if the swelling is severe and affecting the breathing you should visit a Veterinarian immediately for an examination. Regards Dr Callum Turner DVM
July 25, 2018
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Cat
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Oliver
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4 Years
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0 found this helpful

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My pet has the following symptoms:
Inappropriate Urination
I gave my male cat Advantage about four hours ago. A few minutes ago he jumped up on my bed and right in front of me peed all over the bed. Just like he was using the litter box. Is there any relationship?
July 21, 2018
0 Recommendations
There is no relationship that I am aware of between using Advantage (imidacloprid) and urinating outside of the litter tray, there are instances when a cat may lick the application site which may result in an increase in thirst and urination but not specifically inappropriate urination. Keep an eye on Oliver for the time being and follow up with your Veterinarian if he makes a habit (make sure to wash the bedding as the smell may cause him to urinate again). Regards Dr Callum Turner DVM
July 21, 2018
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Domestic short hair cat
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Jet
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17 Years
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0 found this helpful

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0 found this helpful

My cat had an allergic reaction with serious skin irritation to a Hart's topical flea medication in the past. I am considering Advantage II, however, my cat is old and somewhat debilitated. He weighs approximately 6 lb due to chronic weight loss and is 17 yrs old. He is an indoor cat. Is this product an option for an elderly cat?
July 16, 2018
0 Recommendations
Skin irritation is the most common cited side effect of topical spot on flea and tick medications; it is really a case of trying another product to see if there is a similar reaction or not, however whichever product you used ensure that there are different active ingredients from the Hartz product. Regards Dr Callum Turner DVM
July 17, 2018
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Tobie
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Mj
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1 Year
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0 found this helpful

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My pet has the following symptoms:
Forming At The Mouth
i put advantage on my cat she a year old and no sooner got it on her she took off like a bat out of hell and i ran after to see she was forming at the mouth, it scared me to death i picked her up and ran to the bath room put her in sink and got as much of the meds off of her and wiped her mouth out and she seem to be better when i did that. so what I am wondering ca i still give it to her or is it best to leave it off ty julia
July 2, 2018
0 Recommendations
Skin irritation is the most common side effect of topical spot on flea treatments, so MJ may have felt some irritation; she then may have tried to lick the medication which may cause foaming at the mouth as well. You did the right thing bathing MJ and rinsing the mouth out, keep an eye on her for now and visit your Veterinarian if any other symptoms present. Regards Dr Callum Turner DVM
July 2, 2018
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American Short Hair
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Tig
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5 Years
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0 found this helpful

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My pet has the following symptoms:
Lethargy
Itchy
I put advantage on my two adult cats. My dog brought in what I thought was fleas (only saw one that might have been a flea but she was itchy too) so everyone got a dose. They both seem a little itchy now. Especially Tig who is probably about ten pounds. He’s the most itchy around his neck where I applied the advantage. I haven’t seen a flea or flea dust on either cat. Is the itching and irritation a bad reaction for Tig? He also seems a little sleepy. Riley and Tig have not been given any flea medication until now.
June 29, 2018

0 Recommendations
The most common side effect reported when using topical spot on medications like Advantage (imidacloprid) is irritation of the application site which may result in itching, redness of the area of application, some hair loss among other symptoms. The active ingredient will be well absorbed by a skin now, so you may bathe the area to remove any residue to see if that makes any improvement. Regards Dr Callum Turner DVM
June 30, 2018
My cat was running around acting crazy and foaming at the mouth,is she allergic or did she get it in her mouth, I just got her yesterday and took her to the vet today,idk what to do! she had her rabies shot and DRC and the Adv.multi.
July 17, 2018
Sylvia T.

My cat is also itchy, have treated a hot spot on her neck area where applied. She rolls and licks alot...I am treating with antihistamine she had for the one and only respitory infection she had and crram. Otherwise it's to the vet soon
Sept. 3, 2018
Amy W.
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Domestic cat
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Foster
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4 Years
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My pet has the following symptoms:
Burnt Skin And Fur, Bleeding
My poor cat had an awful skin reaction to this medication. It literally burned his fur and skin where the product was applied. He has a huge bald spot that was bleeding and is extremely irritated.
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Maine Coon mix
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Stripe
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3 Years
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0 found this helpful

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My pet has the following symptoms:
Fainted
With 1-2 minutes after applying the medicine my cat Let out a low meow ( almost slow motion sounding) and passed out. I went over and picked him up. In a couple seconds he came to and looked at me. The support rep was very nice, and had not heard of this happening before. It was the first time for us, and it’s the third month of use. Please call in if it happens, so they know. They will ask for the lot number. We used the large cats version (he is 11lbs). Otherwise there are no fleas
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