Whole Dog Journal's Blog September 27, 2018

Hold Off on Those Oral Flea-Killing Medications

Posted at 09:45AM - Comments: (23)

The FDA has linked some flea control products to neurological damage in dogs and cats.

On September 20, the FDA issued a communication for pet owners and veterinarians, warning about the potential for neurologic adverse events following the administration of certain flea and tick products to dogs and cats. The products named in the release are oral products, available by veterinary prescription only, that contain isoxazoline-based ingredients. These include Bravecto, Credelio, Nexgard, and Simparica.

As we described in September 2017, both Nexgard and Simparica have verbiage on their package inserts that say, “Use with caution in dogs with a history of seizures or neurologic disorders.” To date, Bravecto has not included this recommendation on its product insert, though we extended this warning to dog owners in our article, based on the fact that the active ingredients in the products use the same mode of action. Credelio is a newer drug, given market approval by the FDA in January 2018; its package insert does include the statement “Use with caution in dogs with a history of seizures.”

nexguard flea control

The FDA communication notes, “In the first three years after approval, the FDA pays particularly close attention to adverse event reports, looking for any safety information that may emerge.” In the case of the isoxazoline-based flea-killing medications, the FDA observed a significant number of “adverse drug experience” reports mentioning these medications and pets that experienced seizures. The FDA has asked the drug manufacturers to add information about this issue to their product labels, and encourages veterinarians to “use their specialized training to review their patients’ medical histories and determine, in consultation with pet owners, whether a product in the isoxazoline class is appropriate for the pet.”

bravecto flea control

The communication did not include any mention of flea-control medications that contain spinosyn-based ingredients (Comfortis or AcuGuard, and Trifexis or ComboGuard), which work in a very similar fashion to the isoxazolines. However, the package insert for these medications include the statement “Use with caution in dogs with pre-existing epilepsy.”

In light of this FDA communication, Whole Dog Journal would like to make the following recommendations:

1. If your dog has ever had a seizure, has a known seizure disorder, or is descended from a breed or family that is prone to developing seizures:

Do not administer to your dog any flea-control product that contains isoxazoline-based ingredients (Bravecto, Credelio, Nexgard, and Simparica) – OR products that contain spinosyn-based ingredients (Comfortis or AcuGuard, and Trifexis or ComboGuard).

2. Until more information is made available by the FDA about the relative risk being posed by these products, we’d hold off on giving ANY dog ANY of these oral flea medications.

comfortis flea control

An exception could perhaps be made for dogs who have severe flea allergy, live in an area where fleas are a constant threat, who suffer serious adverse reactions to topical flea-killing pesticides, and who have taken these oral products previously without any adverse reactions. (Read carefully: That would encompass a very tiny pool of potential candidates.)

3. As we noted in our September 2017 article, oral products that kill fleas pose many disadvantages over topical flea-killing pesticides.

Most important is the fact that, once consumed, there is no way to reverse or neutralize their activity in case of an adverse reaction. In contrast, if a dog has an adverse reaction to a topical pesticide, the dog can be thoroughly washed and re-washed to reduce the product’s absorption and shorten its effect on the dog.

4. The FDA did not include information about what specifically prompted the publication of its communication.

Has there been a spike in the number of reported cases of seizures among dogs (and cats) treated with these drugs? Or are the numbers of seizures being reported far greater than the pre-market approval studies led the FDA to expect? We have asked the FDA for this information and will report further as we learn more.

Comments (23)

Addendum: Heís had no problem with this collar despite having severe skin allergies and frequent ear infections that have him to the vet at least every month. Highly recommend.

Posted by: fox2514 | October 12, 2018 2:43 PM    Report this comment

I stopped using spot-on flea treatments many years ago on my other dog as he was getting older.
When I adopted my present dog and took him to the vet for his first check-up the vet prescribed an oral flea treatment, that was totally ineffective (sorry canít remember the name), but he got fleas.
At that time, I did some research and speak to some vets and decided to use a Seresto collar. Several vets and vet techs told me they used it on their pets.
The pluses are it lasts for as long as 8 months, is waterproof. Itís not like the flea collars of old where you had to be afraid to pet your dog. It is a bit expensive if you buy it at PetSmart, but you can find it cheaper online, but if you actually do the math it works out to be cheaper overall.
Since I live in PA and we tend to have lots of humidity, I will keep a collar on him from April (or May)-and remove mid December.

Posted by: fox2514 | October 12, 2018 2:39 PM    Report this comment

Any ideas on tropical climates? Any of the above treatments listed by other commenters are not effective in tropical climates (Costa Rica) I am currently using Trifexis which does the job, but I do not like using it....but it is the lesser of the two evils. One being getting eaten alive by insects (literally) or the risks stated by these manufacturers....a real dilemma.

Posted by: Hounds of Diana | September 28, 2018 4:42 PM    Report this comment

Our dog is sensitive to flea bites as well. So here is our protocol. I'm happy to say it works for us.
- During flea season we wash our dog once every two weeks using a shampoo with neem oil and wash her bedding every bath time as well.
- Topical NATURAL drops made by a company called Arava are effective and safe as the drops contain essential oils like geranium, lemongrass, cedar, citronella, etc. We purchased them from amazon.com.
- Our dog gets a daily dose of cod liver oil and hemp seed oil both of which help promote healthy skin and coat

Posted by: Girlinoregon | September 28, 2018 1:33 PM    Report this comment

I have been using Bravecto for the past couple of years on my two dogs. When I read this article today I became alarmed, particularly because my younger dog was diagnosed with encephalitis, as manifested by seizures, about 20 months ago. I immediately rang my vet's office to request a refund for two packages of this very expensive medication, as I cannot risk his health given his neurological condition (which thankfully is stable). But what alternatives are there for dogs who want to play in a park?

Posted by: littlecorgi | September 28, 2018 1:05 PM    Report this comment

My dog is having some problems with allergies, and we're working with a vet to identify them and get them under control. My dog appears to be very allergic to flea bites. I had just given her first dose of Simparica when this warning came out (I had been using Advantage, but it has lost some effectiveness over the years and no longer seems to offer full protection). I researched alternatives, but the oral products are definitely more effective than any of the topicals, plus I can bathe my dog as often as I want, which helps with environmental allergies, when using oral flea products.
The FDA warning was primarily to make the companies who manufacture these products include a warning about possible neurological effects in their product inserts, but as far as I can tell, the drug is unlikely to cause problems in normal dogs (those not prone to seizures) at the recommended dose. I have decided to continue giving Simparica to my flea-allergic dog, as she had no problems with the first dose, and the only problem my vet has seen when prescribing this drug is occasional stomach upset. At this time, the need to keep her completely flea-free outweighs the small risk associated with the medication, especially since it is sized appropriately for my small dog (less risk than if the dose was for a wider weight range).
I will continue to use Advantage as needed with my other dog, who does not have a flea allergy and therefore does not need the stronger protection that the oral medications offer.

Posted by: Mary Straus | September 28, 2018 11:57 AM    Report this comment

So are there any recommendations for flea and tick control? I had a welsh terrier who had his first seizure on his 3rd birthday. I had his seizures pretty well-controlled by feeding him only what I cooked specifically for him and eliminating all preservatives. UNTIL I gave him his monthly flea and tick medicine. Anything I gave him caused seizures. My vet told me to try a topical. Big mistake. I applied it, and within five minutes, he had jumped into my lap and had a seizure like none before. He then proceeded to cluster seize and had five or six within an hour as I frantically bathed him to get the medication off him. It was horrendous! So we went back to the oral meds and anticipated ONE seizure every month. Now I have a healthy wheaten/poodle mix. He vomited repeatedly about five times after Nexgard, and he has two full days of diarrhea after Simparica. A dog I had between my welsh and this one tolerated Sentinel well. Does anyone know anything about it? My vet doesnít seem to want to prescribe it. He pushes Nexgard and Simparica.

Posted by: Lulukay | September 28, 2018 11:49 AM    Report this comment

We have had our three year old Terrier/Poodle mix on Nexgard during the summer months since we adopted her at three months. We noticed that she would occasionally collapse when she got very excited (seeing another dog on TV or when we would come home from work). She would fall to the floor...her legs would completely give out...like someone just pressed the off switch. It would take her a few minutes to regain her balance. We took her to the vet a few times and they said she was probably having some sort of minor seizures that were caused by the over excitement, which never really made much sense to me. After reading this article, I now realized that she doesn't have any episodes during the Fall and Winter seasons when we aren't giving her Nexgard. I'm not certain the drugs are causing the seizures, but it's highly likely given the timing. Either way, I've learned these drugs are toxic regardless of the seizures and won't be giving them to my dog from now on.

Posted by: amolavi | September 28, 2018 8:42 AM    Report this comment

Like AgilityMom (comment above) we have used beneficial nemotodes for many years-- when we had our two Bostons and now that we have our Chihuahua. No fleas. No bad effects. A great product.

Posted by: JanS | September 27, 2018 6:42 PM    Report this comment

In 2017 I adopted an Australian Shepherd from a rescue organization. The first time I saw him I noticed tremors in his legs, but the rescue said their vet didn't know what was causing them. I adopted him anyway and we quickly bonded. The tremors never slowed him down and he got along well with our three female dogs, though, for some reason, two of the other dogs started fighting after he came. Each fight was more intense and violent.

I decided to have his DNA tested and that's when I learned that herding breeds can carry a gene mutation that makes them highly sensitive to drugs and chemicals. There were times that his entire demeanor would change. He'd be happy and sweet one minute and the next his eyes would start drooping and he looked evil and I wondered if he was going to bite me. One morning I was sitting at my computer, about 10 feet away from the couch on which my husband was sitting. The dog went up to my husband and wanted petting and loved on my husband, laying his head on my husband's chest. He went back three times and the third time, without prevocation, he lunged and bit my husband in the face. My husband is a veteran with PTSD. Dogs have always been a comfort to him, so he could not be around a dog he couldn't trust. It tore my heart out, but I had to return the dog to the rescue organization four months after we got him.

Before adoption the rescue told me the dog had been surrendered by his previous owner covered in ticks. I suspect that he was given multiple tick treatments. I will forever love that dog, but I truly believe that he was brain damaged from those flea/tick chemicals. I've been rescuing/adopting dogs for over 45 years and have NEVER had to return a dog. It was the most painful, heartbreatking experience I've ever had and I went into a severe 6 month deprression. By the way, I had taken him to multiple vets and none of them even attempted to help him. I wish there had been some kind of detox or something they could have done. The rescue closed down and ended up transferring him out of state and he was adopted at least two more times. I still pray that SOMEONE was able to help him.

Posted by: DLittle | September 27, 2018 6:17 PM    Report this comment

This is so troubling to read, thank you for posting. I don't know what to do because Frontline does not work as well as Nexgard, and my dog (8 yr old corgi) is very allergic to fleas (just one bite causes a systemic response). And fleas and ticks are a huge concern in my area.

I have always been cautious and skeptical about using any of these toxins on my dogs. However, I have had to compromise (especially as my husband and vet do not share my concerns) because Nexgard has worked so well on fleas and ticks.

I do not give the Nexgard every month ( I space it out to nearly 2 months or so, believing it's still effective that long). I'm going to have a hard time convincing my husband that we should be concerned about this new FDA warning. But without more info, there's not much I can do. What do other pet parents do in this situation?!

Posted by: corgifamily | September 27, 2018 4:05 PM    Report this comment

I don't want to expose my dogs to toxic chemicals so I don't use flea or heart worm meds. I had a problem with fleas and ticks in the yard - and on my dogs - a few years ago. I started spreading beneficial nematodes in the back yard every spring and I haven't had a flea or tick problem since. The nematodes feed on flea larvae and also kill other pests like grubs - but they don't harm worms or other good-for-the-soil critters. As such, my dogs are confined to their own yard and we don't walk the neighborhood so they don't pick up fleas or ticks from other yards. I swear by the beneficial nematodes. You can get them at some garden supply stores and I order mine on line.

Posted by: AgilityMom | September 27, 2018 3:22 PM    Report this comment

Duckluv: I am very intrigued about your experience with neem oil. I was wondering - during flea season - how often do you need to reapply it? Also - you put it in a bottle of conditioner. Was this a spray on coat conditioner?
I bought a package of Credelio yesterday. I am thinking of taking it back.

Posted by: Shastablade | September 27, 2018 2:47 PM    Report this comment

We used those vet-recommended spot treatments on our dogs with disastrous results. Both dogs developed weeping skin sores, and one had reactions so bad her sinuses and mouth (mucous membranes) were so inflamed she refused to eat. We immediately bathed them but the damage was done. (We had to use laser treatments on the girl to get the swelling to go down.) We reported the reactions to the FDA. We vowed never to use these toxins agai on our dogs. Instead, we vacuum the house thoroughly once or twice a week during flea season, wash blankets and bedding in hot, soapy water, use a non-toxic cedar-based topical spray treatment on coats twice a day, and use food-grade diatomaceous earth (not industrial or for pools) on upholstery and bedding. We now rarely have fleas on the dogs, on us or in the house.

Posted by: Three Dog Mom | September 27, 2018 2:47 PM    Report this comment

I use nitenpyram if fleas are evident. Once the fleas are killed I start them on monthly lutenuron. Haven't had a problem in years.

From what I gather these medicines are about the safest internal flea remedies possible. Is my information correct?

Posted by: gmes | September 27, 2018 2:20 PM    Report this comment

I was originally very skeptical about flee and tick meds, and per my vet recommendation began using First Shield anyway. I figured, if reaction wash off and discontinue use. No reaction in any of my dogs... it turned out to be the best possible medication... there was a massive bed bug breakout in our area. Our house was not only exposed to the bed bugs but developed them in the upstairs bedrooms that the dogs did not go into. I never got them in my bed, and trust me... I KNOW what they look like. I never got them in the living room, no where else because the dogs had free roam of everywhere but the upstairs bedrooms. I later moved to the new house, been exposed twice to bed bugs again, and we never got them again. When our vet offered the pill medication, I found out it does not contain the ingredients that are preventing and killing the bed bugs (because they bite the dog and ingest chemicals that prevent them from laying eggs). Therefore, I did not switch to the pills. I don't think I will ever stop using First Shield, my girls don't mind and I love not dealing with fleas and bed bugs. I know SO MANY people who keep getting both.

Posted by: jeschainks-jrchase@yahoo.com | September 27, 2018 1:48 PM    Report this comment

I have never used any chemical flea/tick treatments on any of our dogs. Our current dog has a history of seizures so I even space out his vaccinations to only 1 at a time spread months apart and only when he absolutely needs them. (ie: rabies). None of our dogs has ever had a flea problem either despite the fact that we live in the Upper Midwest where it's hot and humid from late May until late September. I only use proven safe, natural treatments and shampoos.

Posted by: SueW | September 27, 2018 1:42 PM    Report this comment

Natural Baltic Amber dog collar --- have that on my Australian Shepherd for the past couple of years. I was very skeptical that it would work, but one day on our walk I noticed about five mosquitos hovering over him. They would attempt to land and would practically bounce back off him! Seeing it with my own eyes has made me a believer!

Posted by: AnaisChanel | September 27, 2018 1:33 PM    Report this comment

My vet gave us Trifexis for our dogs, saying the Frontline was not effective enough. But I read the trial studies both US and EU. I brought it back to the vet. The seizures and the way it worked to kill parasites was too much for me.

Posted by: LouH | September 27, 2018 1:12 PM    Report this comment

I haven't used the oral flea/tick/heartworm prevention in about a year. I don't like the thought of my mini doxie ingesting any of those chemicals, so, I started using the flea & tick tag from Only Natural Pet.
I live in NE Ohio and haven't seen any fleas or ticks since I started using it. (To be honest, I didn't really see any before I started using it, but, I've heard others mention how there is a huge flea/tick problem this year.) I was wary when I first bought it but now I'm a believer.

Posted by: joandmar | September 27, 2018 1:11 PM    Report this comment

Iíve been using the Seresto collar on my dogs for the last several years, and have been pleased with the results. No fleas or ticks (knock on wood!) and no neurological or digestive problems like they had with the topical or oral products.

Posted by: Morgansmom01 | September 27, 2018 1:05 PM    Report this comment

Over the past decade or so my family and I have given our dogs Comfortis, sparingly. We wait for "Flea Seaon" to roll around and we administer the tablet. Sometimes all it takes is one tablet and the dog remains flea-less until next Feb-March-April. Sometimes the monthly dose continues for 2-3 months.

The dogs receiving Comfortis have ranged in size from 55lbs to 4.5lbs. Our cat even had his Comfortis given to him, prior to his death.

We have never once seen any ill effects from this oral flea control. We much prefer the oral method to that of dripping topical medications/pesticides onto the back of the pet's neck.

If we had to give up administering Comfortis to our dogs, that would be done, but then what's the alternative?

Posted by: MiTmite9 | September 27, 2018 12:57 PM    Report this comment

So, this is regarding alternatives. I used Advantage (the regular one) on all of my pets for 20 years, without problems. I did notice that, after applying it, even I would feel a little weird, somehow, for a short while. Anyway, I used it on a new dog one year, and he seemed sick-ish for a day or two, so I decided not to use it, again. My usual practice was just to use it if they had fleas, and go long times between applications. So, by the next Summer, I had forgotten, and used it on him, again. He failed quickly and had to spend the weekend in the ER on I.V. steroids and some antihistamines. We almost lost him. After that, I read up on the adverse effect reports and found that a lot of dogs have been sickened or killed by it. So, the next Summer, we had a huge flea infestation on the dogs and in the yard. I tried DE to no avail, and then read on my bottle of neem oil (organic, not for the garden, for humans and pets) that 10 drops in a 16 oz bottle of conditioner would either kill or repel fleas on dogs. (There has been some controversy about whether or not you can use it on cats, with recent info saying you can, if it's pure and organic; but I don't really know about that. ) . The first day I used it, I just put it sort of around the major dog body parts, and found fleas the next day only on the parts where I hadn't put it. So, I put it all over, but then found fleas around their eyes and mouth. So, I really put it on every millimeter, and no more fleas on the dogs, down from combing off 40 fleas per day off of each dog! After 2 months of that, there were no more fleas, even in the garden, and they never came back. I also discovered that neem oil is better for preventing and treating diaper rash than diaper creams or powders - I had a handicapped dog who wore diapers, and after I started using the neem, he never had more than the very beginning of a rash. Also works on hot spots and other rashes.

Posted by: duckluv | September 27, 2018 12:52 PM    Report this comment

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