NexGard Allergies in Dogs
Written By hannah hollinger
Published: 09/11/2016Updated: 10/21/2021
Veterinary reviewed by Michele K.
NexGard Allergies in Dogs - Signs, Causes, Diagnosis, Treatment, Recovery, Management, Cost
What are NexGard Allergies?
NexGard is a flea and tick protection system that comes in a chewable pill for dogs. This tasty and soft chew has been approved by the FDA and is considered safe for dogs. The active ingredient, afoxolaner, has been proven to effectively treat and control ticks and fleas for one month when given regularly. This item is from the makers of Frontline.
Although many dogs tolerate NexGard quite well, there are specific side effects that are listed on the label. When you are giving your dog this chewable tablet, it is essential to be familiar with the side effects that can occur. If your dog does have adverse effects to this medication, consult your veterinarian without delay.
Many flea and tick treatments do come with warnings about side effects; however, it is vital you give your dog some sort of flea and tick preventative to avoid Lyme disease and other conditions caused by flea and tick infestations. This is especially important if your dog goes outside on a regular basis and if you live in an environment where fleas and ticks are very common.
NexGard allergies in dogs occur when dogs have an allergic reaction to or suffer from side-effects of this popular flea and tick treatment. The active ingredient, afoxolaner, may not agree with all dogs that ingest this oral preventative.
Paying to treat an allergic reaction to NexGard out of pocket can be a major financial burden. Fortunately, most pet insurance companies reimburse claims within 3 days, putting 90% of the bill back in your pocket. In the market for pet insurance? Compare leading pet insurance companies to find the right plan for your pet.
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NexGard Allergies Average Cost
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Average Cost
$400
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Symptoms of NexGard Allergies in Dogs
Signs of an adverse reaction to NexGard will vary from dog to dog. Frequently diagnosed reactions to this flea and tick treatment include:
  • Dry and flaky skin
  • Loss of appetite
  • Vomiting
  • Diarrhea
  • Lack of energy 
Types
There are various types of active ingredients in flea and tick treatments which include:
  • Pyrethrins
  • Pyrethroids
  • Etofenprox
  • Fipronil
  • Methoprene
  • Methylcarbamate
  • Imidacloprid
  • Amitraz
  • Selamectin
  • Nitenpyram
  • Fluralaner
  • Sarolaner
  • Lotilaner
Causes of NexGard Allergies in Dogs
Causes of NexGard reactions in dogs are primarily due to a reaction to the active ingredient, afoxolaner. Specific causes include:
  • The hypersensitivity towards the main ingredient
  • An over-reactive immune system
  • Afoxolaner causing skin irritation to the sensitive skin of the dog
Diagnosis of NexGard Allergies in Dogs
If you have recently started giving your dog NexGard and they are showing signs of a reaction, it is crucial to stop giving them the preventative medication and contact your veterinarian. When you take your dog to the clinic, take the package of this flea and tick preventative treatment to help the veterinarian come to a diagnosis. The veterinarian will take a closer look at the ingredients, asking questions pertaining to when the signs began.
To come to a diagnosis, the clinical team might perform various tests, such as blood work, urinalysis, and a biochemistry profile. Depending on your dog’s signs, your veterinarian may want to perform other assessments; however, this will depend on your dog's present condition.
If your dog has skin irritation, the medical professional will take a closer look to determine if a skin test is required to be sure the inflammation and soreness is a result of the NexGard. Your veterinarian may decide to wait before a costly test is conducted; once your dog stops taking the tablets, the signs may resolve. It is important to understand that this may take some time, as this flea and tick treatment is given once a month, and it may still be in their system for up to 30 days. Once your veterinarian suspects that your dog is allergic to the product, they will advise you to stop giving your companion the treatment and will recommend an alternative method to help prevent fleas and ticks.
Treatment of NexGard Allergies in Dogs
Effective treatment of a NexGard reaction will be to stop administering this chewable pill to your dog. Unfortunately, there is no immediate clinical method to remove the drug from your pet's system but depending on your dog's condition, supportive treatment may be offered. Treatment methods that can help in the meantime are:
Topical Medications
Applying a topical medication to your dog’s skin, if the reaction caused a skin irritation, will ease the sensitivity and discomfort. Topical medications may help your dog stop itching and licking the skin.
Alternate Preventatives
Finding an alternate preventative for your dog’s flea and tick treatment is essential. You may want to research other alternatives to keep your dog free of these parasites. Do not try to treat the fleas and ticks without consulting your vet in case your dog has a sensitivity to other products. Your medical professional can also suggest specific flea and tick treatments.
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Recovery of NexGard Allergies in Dogs
If your dog is often outdoors it will be important to find protection against infestations that works for them, yet does not include such harsh ingredients. Protecting your pet from fleas and ticks prevents more serious conditions from occurring, such as Lyme disease and other illnesses.
Once you find an alternative that works for your dog, it may take them some time to adjust. Monitor your dog’s skin and coat for infestations to be sure the new preventative is working properly.
If your dog develops signs of a reaction after you have removed the Nexgard chewable from their diet, contact your veterinarian. Your veterinarian may then decide to do further allergy testing to identify the ingredient they are allergic to.
NexGard Allergies Average Cost
From 407 quotes ranging from $200 - $800
Average Cost
$400
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NexGard Allergies Questions and Advice from Veterinary Professionals
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Rottweiler
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One Year
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9 found this helpful

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9 found this helpful

My pet has the following symptoms:
Diarrhea & Lethargy
We gave our beautiful dog her monthly nexguard chewable yesterday with her morning feeding and this morning she had diarrhea 1 time. She is sleeping more today too. How long will her lethargy last from side effects?
July 14, 2020
Answered by Dr. Michele K. DVM
9 Recommendations
Thank you for your question. I would not expect the lethargy or diarrhea to last more than 12-24 hours. You can feed her a bland diet of boiled white chicken and boiled white rice for a couple of days to help with the diarrhea, and if she continues to be lethargic through tomorrow or starts vomiting or doesn't want to eat, then it would be best to have her seen by your veterinarian, as they can examine her and make sure that she is okay. I hope that she is back to herself very soon!
July 17, 2020
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Mix German Shepard, Labrador, Husky
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8 weeks, 3 days
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0 found this helpful

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0 found this helpful

My pet has the following symptoms:
Vomiting, Lack Of Energy And Appetite
Is there anything we can give our puppy since she seems very ill. She’s a very active puppy and has been feeling down since we gave her NexGard Friday evening.
July 14, 2020
Answered by Dr. Sara O. DVM
0 Recommendations
Hello, So sorry to hear about your puppy. We worry about parvovirus in young puppies. It would be best for your puppy to see a vet for a parvo test. They can also prescribe your dog medication to help your dog feel much better. I hope your dog starts to feel better soon
July 14, 2020
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Dachshund
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Bruno
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14 Years
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0 found this helpful

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0 found this helpful

My pet has the following symptoms:
Seizures & Loss Of Use Of Back Legs
My dachshund is 14. I started giving him NexGard about 6 months ago and continued monthly. During that time he started have seizure episodes. It didnt occur to me that it was from the Nexgard. I thought it was due to him being old. I finally took him to the vet, and the vet told me that it his symptoms were probably due to the nexgard. I have stopped giving it to him and its been a little over a month. He is still having seizures and loss of use of his back legs. The loss of back leg use started only about a month ago. What i would like to know is if my dog will recover and stop having the seizures or if the damage is permanent.
Aug. 2, 2018

Answered by Dr. Michele K. DVM
0 Recommendations
I haven't heard of that reaction from Nexgard, and I'm not sure that those two things are related. Dachshunds are prone to back problems that can cause hind end weakness and paralysis, and that may also not be related to the seizures. If he isn't using his back legs, he needs to see your veterinarian right away. If he is still having seizures, he may need medication to control those. I hope that all goes well with Bruno.
Aug. 2, 2018
Thanks for the reply but my question wasnt answered. Regardless of the back legs, will my dog recover from the seizures caused by the nexgard now that he is off of it?
Aug. 2, 2018
Bruno's Owner
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Pomeranian
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teddy
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12 Months
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0 found this helpful

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0 found this helpful

My pet has the following symptoms:
Nothing
i have the nexgard treatment should i give him i heard that this treatment sometimes be dangerous i dont know if i should give him it and does the poms have some type of allergics to this product? thanks...
June 13, 2018
Answered by Dr. Michele K. DVM
0 Recommendations
Nexgard is a very commonly used, safe product to prevent flea and tick infestations. Most dogs, including Pomeranians, tolerate it quite well. Since I don't know anything about Teddy's health status, if you aren't sure if you should use this product, it would be a good idea to call your veterinarian and make sure that it is okay for him to take.
June 14, 2018
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Kuvasz
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Tarfu and Makeda
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5 Years
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0 found this helpful

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My pet has the following symptoms:
Diarrhea
We gave our first dose of NexGard to our two Kuvasz 15 days ago. Coincidentally, since then they have both have been dealing with diarrhea and are now assuming they are related. We have another dog that didn’t get NexGard and does not have diarrhea. We have tried boiled chicken and rice, elimination of all treats, Imodium and Flagyl. The male pup seams to be improving with mostly firmed stool now. The female now has half of the stool semi formed followed by all liquid still. If this is from the NexGard, how long can we expect this to continue and is there anything else we can try? Anne
May 18, 2018
Answered by Dr. Michele K. DVM
0 Recommendations
Every dog is an individual, and they will respond to the treatment for their diarrhea differently. 15 days is a long time to have diarrhea, and you are giving all medications that should help, including the bland diet . If they haven't been seen for a recheck with your veterinarian, that may be a good idea if things aren't continuing to improve. You do seem to be doing everything that you should for an intestinal upset. I hope that they both continue to improve.
May 18, 2018
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Border collie lab
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Missy
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6 Years
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2 found this helpful

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2 found this helpful

My pet has the following symptoms:
Loss Of Appetite
Lethagic
My 6 year old Border collie mix went in for her yearly vet visit where Nexgard was recommended. She was fine until I gave her the chew. She has been extremely lethargic with little or no appetite. The only thing that has changed was the Nexgard. At this point, I'm not sure if there is anything that can be done. I have been reading that there is no way to remove the medication from the dog's system. I am so regretful for giving her this medication.
NexGard Allergies Average Cost
From 407 quotes ranging from $200 - $800
Average Cost
$400
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