Bravecto/Isoxazoline "poisoning" or Idopathetic Epilesy in Hungarian Vizsla - any vets on here?

[wytonpjs]

I've previously posted on here advocating the use of Bravecto anti-tick/flea/worm treatment for dogs and indeed, even suggested I want some for me as the dog never gets tick but I do! However, 2 weeks ago, our 4-yr Hungarian Vizsla rescue bitch suddenly out of the blue had 3 seizures in one evening. With an Emergency Vet consultation and extensive follow-up with my normal vets we are well North of £1000 and none the wiser despite extensive tests and checks. Indeed, we are now on the "wait and see what happens" strategy before possible elevating this to Langford for MRI/neurological/spinal-fluid testing. As she is a rescue (my second rescue out of 5 Vizslas owned) we are struggling to get breed history to see if there's any genetic predisposition. Life under COVID has been very tame compared to my normal weekly stalking and we are sure that there were no out-of-the-ordinary triggers or possible poisoning that could have brought this on. Apparently, and this was news to me as a Vizsla owner for 40 years, the breed is quite prone to epilepsy (Idopathetic Epilesy) although none of our other 4 Vizsla were affected and, despite moving in some breed/Field Trial circles, it never cropped up.

Looking laterally, I've been Googling the hell out of this condition and discovered that the US FDA forced Merck in 2019 to add seizure warnings to their Bravecto product documentation resulting from use of Isoxazoline (also known as Fluralaner or 4th generation tick/flea treatment). The UK leaflets are not as similarly descriptive. However, there is a wealth of information on other forum's posts, articles and indeed some veterinary specialist write-ups reinforcing the link between Bravecto and seizures in dogs. Are there any other former users of Bravecto or vets on here that could add substance to my suspicions that is possibly a result of Bravecto poisoning? At the present, I've stopped administering it and am looking for a replacement tick treatment that does not rely upon making my family pet highly toxic.

 

[arron]

Interesting ! ,,,I will watch this thead progres, ps hope your dog makes a speedy recovery and not be repeated.( I use it for my viszlas )

 

[Fosbery Holster]

I too have advocated the use of Bravecto anti/tick/flea treatment in dogs and have used it for some years until quite recently.
We used it on both our dogs a GWP and HWV, the HWV was diagnosed some time ago with Epilepsy but controlled the Epilepsy with Epiphen tablets as prescribed by our vet with little or no problems until early 2020 when we administered the Bravecto as usual, was it the same day or next day the HWV can’t remember exactly but she went into a seizure, she always comes to me to let me know it’s time for a seizure.
I consulted our vet on the phone who knows our dogs intimately and she said not to give the bitch any more Bravecto tablets, they can have a reverse effect on an Epileptic dog.
The then prescribed tick/flea treatment by the vet was Advantix .
We hadn’t consulted our vet before giving our dogs Bravecto we took it on ourselves, with hindsight we should have.

 

[malmick]

I've moved my ESS and Sprocker on to Simparica from Bravecto after similar research. The ESS seemed to sniff it out before hand and just refused to take it.

 

[NoIDeer]

Our dogs seemed to tolerate bravecto, I lost my bottle and went back to advantix. To many ??? for me.

 

[GrizZLy9]

How long after the last Bravecto treatment did the 3 seizures occur?
ps "idiopathic" is the word

 

[wytonpjs]

How long after the last Bravecto treatment did the 3 seizures occur?
ps "idiopathic" is the word

Apologies - type fast, regret at leisure. We got her at 18 months, started Bravecto about 2 months after we got her and she’s nearly 4 now. In the dosage cycle, the episodes were towards the very end of the cycle cover, ie it was 2 and a half months since she had her last dose. I’m at a loss to understand why it could be Isoxazoline triggered given she had 2 years plus of treatment without effect but equally, why would a healthy and active 4 year-old suddenly have 3 consecutive seizures without any other discernible trigger?

 

[Fosbery Holster]

As l understand it from our vets Epilepsy can rear its ugly head anytime within the lifetime of the dog, not necessarily brought on with the use of Bravecto but Bravecto shouldn’t be administered to a dog with the disease.

Our present HWV started with Epilepsy when she was in her third year and after being diagnosed with the problem (quite mild symptoms) we were able to kept it under control with Epiphen.

With our dogs we didn’t administer a full yearly treatment, only used it prior to our perceived tick/flea season.

The prescribed treatment Epiphen had a dramatic effect on the dog immediately to the extent you wouldn’t have believed she had the disease, but it has side effects, drinking lots more than usual and constantly looking for food, although mild the side effects can become irritating for the owner.

Since her last seizure and changing the tick/flea treatment to Advantix there has been no more seizures.

Our first HWV developed Epilepsy at the age of twelve months but unfortunately for her nothing could be done to give her a somewhat normal life and within two weeks she was euthanised, sad end to her short life

 

[wytonpjs]

As l understand it from our vets Epilepsy can rear its ugly head anytime within the lifetime of the dog, not necessarily brought on with the use of Bravecto but Bravecto shouldn’t be administered to a dog with the disease.

Our present HWV started with Epilepsy when she was in her third year and after being diagnosed with the problem (quite mild symptoms) we were able to kept it under control with Epiphen.

With our dogs we didn’t administer a full yearly treatment, only used it prior to our perceived tick/flea season.

The prescribed treatment Epiphen had a dramatic effect on the dog immediately to the extent you wouldn’t have believed she had the disease, but it has side effects, drinking lots more than usual and constantly looking for food, although mild the side effects can become irritating for the owner.

Since her last seizure and changing the tick/flea treatment to Advantix there has been no more seizures.

Our first HWV developed Epilepsy at the age of twelve months but unfortunately for her nothing could be done to give her a somewhat normal life and within two weeks she was euthanised, sad end to her short life

So sorry to hear of your experiences. Whilst its a possibility the 2 are unrelated, I'd be irresponsible if I didn't discontinue Bravecto now. Ruby is like a third "daughter" in our household, the swetness natured, loving and best trained V we have ever owned - it was heart-breaking to see her seizures. We are all praying this does not turn into Idiopathetic Epilepsy..........................

 

[Fosbery Holster]

So sorry to hear of your experiences. Whilst its a possibility the 2 are unrelated, I'd be irresponsible if I didn't discontinue Bravecto now. Ruby is like a third "daughter" in our household, the swetness natured, loving and best trained V we have ever owned - it was heart-breaking to see her seizures. We are all praying this does not turn into Idiopathetic Epilepsy..........................

The young bitch we euthanised was diagnosed with ldiopathic Epilepsy, she suffered with catatonic grand mall seizures, and towards the end suffered continual seizures, there was no hope I’m afraid.

l kept a diary of the seizures, duration, dates etc, and before we made the decision to let her go the Vet very kindly read my diary completely before commenting there is only one outcome.

l do hope for you and the dogs sake everything works out well to the benefit of you both.

My very best regards.

 

[Sikadave84]

Sorry to hear of this mate and hope she makes a full recovery ASAP. I’ve used Bravecto with our lab since we got him as a pup. He’s 4 now and never had a seizure that
I also only use it as we approach the season for ticks as well

 

[GrizZLy9]

In the dosage cycle, the episodes were towards the very end of the cycle cover, ie it was 2 and a half months since she had her last dose.

That's quite a long time after the last treatment. Fluralaner concentration in the circulation would likely peak within a day of tablet ingestion, and then gradually decay according to its half-life of ~2 weeks or so. So by 2.5 months post-treatment, concentrations in plasma are going to be pretty low. If Bravecto was triggering seizure activity, I would expect it to occur very early in the treatment cycle - within the first day or so after treatment, when fluralaner concentration is at its highest. I fully understand your decision to stop with the Bravecto treatment, but it may have nothing to do with Bravecto - there are lots of reasons why dogs have seizures, and it can be tough to understand and treat them sometimes. Best of luck getting to the bottom of it.

 

[wytonpjs]

That's quite a long time after the last treatment. Fluralaner concentration in the circulation would likely peak within a day of tablet ingestion, and then gradually decay according to its half-life of ~2 weeks or so. So by 2.5 months post-treatment, concentrations in plasma are going to be pretty low. If Bravecto was triggering seizure activity, I would expect it to occur very early in the treatment cycle - within the first day or so after treatment, when fluralaner concentration is at its highest. I fully understand your decision to stop with the Bravecto treatment, but it may have nothing to do with Bravecto - there are lots of reasons why dogs have seizures, and it can be tough to understand and treat them sometimes. Best of luck getting to the bottom of it.

Totally understand - hoping for the best, fearing the worst.

 

[Scandially]

I Googled Bravetco side effects 6 years ago and that was enough to put me off.

 

[Buchan]

I think it is unlikley to be the Bravecto that is the cause of the epilepsy, but I would probably use another form of flea/tick control in future, simply to reduce the variables. Most epilepsy cases have no specific cause that can be found, even with an MRI scan and so just have to be controlled. Even then, the medication used will probably be adjusted so that you can expect the occasional brief siezure. It's a balance of a sedated dog vs normal dog. I hope she settles down, you should still be able to work with her, although I wouldn't personally breed from her.

Bravecto (an isoxazoline as reported) acts by blocking a specific "gated-channel" (specifically a GABA-Chlorine) in a cell membrane. These occur in nerve tissue and regulate the flow of potassium and sodium so allowing the cell to have a charge. In nerve tissue the charge/discahrge of each cell, one to another, is what allows nerve impulses to move. If the channel is blocked, then the cell remains in a state of excitement. As isoxazolines bind to insect channels more than mammal ones, that how the drug kills the flea/tick and not the dog/human with a form of active paralysis. But, from the above, you can see an explanation of how Bravecto may affect an animal with an existing predisposition to epilepsy, which is why the instructions say use with caution in epileptic animals.
In context, between 2014 and 2016, 18 million doses were sold in the EU, with 2,144 suspected side effect reports (I couldn't see what they were).

 

[wytonpjs]

I think it is unlikley to be the Bravecto that is the cause of the epilepsy, but I would probably use another form of flea/tick control in future, simply to reduce the variables. Most epilepsy cases have no specific cause that can be found, even with an MRI scan and so just have to be controlled. Even then, the medication used will probably be adjusted so that you can expect the occasional brief siezure. It's a balance of a sedated dog vs normal dog. I hope she settles down, you should still be able to work with her, although I wouldn't personally breed from her.

Bravecto (an isoxazoline as reported) acts by blocking a specific "gated-channel" (specifically a GABA-Chlorine) in a cell membrane. These occur in nerve tissue and regulate the flow of potassium and sodium so allowing the cell to have a charge. In nerve tissue the charge/discahrge of each cell, one to another, is what allows nerve impulses to move. If the channel is blocked, then the cell remains in a state of excitement. As isoxazolines bind to insect channels more than mammal ones, that how the drug kills the flea/tick and not the dog/human with a form of active paralysis. But, from the above, you can see an explanation of how Bravecto may affect an animal with an existing predisposition to epilepsy, which is why the instructions say use with caution in epileptic animals.
In context, between 2014 and 2016, 18 million doses were sold in the EU, with 2,144 suspected side effect reports (I couldn't see what they were).

Buchan

Many thanks for that - makes full sense. Ruby was neutered before being re-homed so, even though we would have loved to have another dog from her as she literally is the best of the 5 we have had the pleasure and joy of living with, it will never happen. Do you have any other recommendations for a better and less "harmful" tick treatment? We suffer badly from ticks where I stalk and it seems to be getting worse - well over double figures last year, one of which developed the classic bulls-eye necessitating heavy anti-biotics. I support the PHE Porton Study too and one of last year's samples was borderline for TBE! At least I've had the jabs for that!

Peter

 

[Buchan]

Interestingly enough there are thoughts about bravecto type drugs (isoxazolines) in humans, if safe it could be ideal.
For the hound, advantix is the best of the rest, only lasts a month. Although ticks for dogs are mostly just a nuisance, no issue with TBE or Lyme really. Ah, you are in "the south" babesia might be an issue - your vet will know

 

[Scotty99]

Sorry to hear of your dogs seizures, it must have been a horrible time. Hopefully you will find a way forward.

Yes Vizslas are prone to epilepsy as a breed and I’ll be interested to see if Bravecto is considered to be a trigger.

I’ve got two HWVs and so far neither has had a seizure. I use Advantix for tick and flea, while maybe not as effective as Bravecto I prefer it as it’s not ingested.

Please keep posting as a lot of people are interested in this.

 

[wytonpjs]

Hi - for those following, I ceased using Bravecto after those fits and she has had none since. All this may be coincidence and we may just have been unlucky with out 5th Vizsla but given the evidence coming out of the US, I believe there is a an increased liklihood that Bravecto can trigger fits. Incidentally, I have not given her any other treatment (planning to move to Advantage) and she does not appear to have picked up any at all unlike me There is probably quite a residual toxic burden so I'm not rushing to apply Advantage until she starts to pick them up. I on the other hand continue to act like a magnet - this from Saturday and probably not deer related:

 

[Fosbery Holster]

Hi - for those following, I ceased using Bravecto after those fits and she has had none since. All this may be coincidence and we may just have been unlucky with out 5th Vizsla but given the evidence coming out of the US, I believe there is a an increased liklihood that Bravecto can trigger fits. Incidentally, I have not given her any other treatment (planning to move to Advantage) and she does not appear to have picked up any at all unlike me There is probably quite a residual toxic burden so I'm not rushing to apply Advantage until she starts to pick them up. I on the other hand continue to act like a magnet - this from Saturday and probably not deer related:

View attachment 203766

Thats absolutely brilliant news about your bitch that she hasn’t had a seizure since stopping the use of Bravecto flea and tick treatment on her........not so good news for you though.......is there a similar flea and tick treatment from the Vets for us mere humans

Thank you for passing on your information to us all here, the best of luck with your bitch for the future.