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A New Treatment for Canine Idiopathic Epilepsy: Pexion

A New Treatment for Canine Idiopathic Epilepsy: Pexion

We recently wrote about canine idiopathic epilepsy, a form of epilepsy where the cause remains unknown. Today we are looking at a new treatment; Pexion.

The severity of epilepsy can vary greatly between individual sufferers. Some dogs may experience a single, isolated seizure, whilst other can experience multiple seizures every week.

Recently Boehringer Ingelheim has announced their latest product for the treatment of canine epilepsy, Pexion® (Pexion) an alternative to the traditional phenobarbital or potassium bromide treatments given to epileptic dogs.

Are you using Pexion?

If you’re dog has been prescribed Pexion, let us know how your dog is getting on in the comments below. Join the discussion on how other dog owners are getting on with Pexion and keep the community updated with your progress. 

What Is Pexion?

Unlike other treatments for canine epilepsy, Pexion contains the active ingredient Imepitoin. Imepitoin acts in a similar manner to previous anti-epileptic medicines, potassium bromide and phenobarbital, in that it works to suppress electrical activity in the brain.

Imepitoin partially activates GABA receptors, which are responsible for reducing electrical activity between nerve cells. This partial activation of the GABA receptors is believed to reduce electrical activity and help prevent seizures. Specifically, Imepitoin also has a weak blocking effect on calcium channels that allow electrical signals to be propagated along nerve cells.

See here for more information about Pexion 

Does Pexion Work?

A study conducted on Pexion during its development compared it to the traditional anti-epileptic medicine phenobarbital. A 20 week study of 226 dogs taking the medications found Pexion matched phenobarbital in efficacy, reducing the occurence of seizures by around 50%. 1

Is Pexion a Better Alternative?

The Pexion study showed that it had an effectiveness equivalent to phenobarbital, however, Pexion may be considered a better alternative as it has less severe side effects.

Unlike phenobarbital, Pexion does not pose a hepatotoxicity risk (liver toxicity). This means the regular testing required to ensure that a dog’s liver remains healthy is not needed whilst being given Pexion.

Treating the Epileptic Dog

It is commonly cited that around 0.5 to 5% of dogs suffer from some form of epilepsy, the severity varying between breeds and individuals. In dogs where seizures occur infrequently  owners may consider not using any medication at all, avoiding the side effects associated with anti-epileptic medications.

In dogs where seizures occur more freqently, such as once a month or more, treatment should be considered.

The introduction of Pexion gives owners and vets a greater choice when it comes to treatment, but does not replace phenobarbital and potassium bromide.

Owners should consult their vet and explore all the possibilities when dealing with an epileptic dog.

Seizure Types That Require Immediate Veterinary Assistance

Cluster seizures – When multiple seizures occur in one 24 hour period
Status epilepticus – A persistent epileptic state that lasts for longer than 5 minutes

For more information about epilepsy, such as the causes, what to do during a seizure and more, see this article.

Disclaimer: This article was written as a response to the release of Pexion and as a follow up to a previous article concerning idiopathic epilepsy. I am not affiliated with the product (Pexion) or the manufacturer (Boehringer). 

Image Credit: Onkel_wart

About James Watts

BSc Bioveterinary Science. Editor of PetSci. When I'm not writing, learning, discussing, or reading about animals, you know it's the weekend!


  1. My dachshund started having seizures shortly before his second birthday about three weeks apart. After all the tests came back normal the vet put him on Pexion. Unfortunately the seizures increased in frequency despite going to the maximum dose. So I have to say that this medication has not worked for my dog. He is now on Epiphen and so far he has not had any more fits. Worried about side effects though.

  2. Hi Wendy
    If your dog has not had other medication for fits/epilepsy, it might be worth changing the drug…
    Talk to your vet and see what he/she says, also show them this website.
    I was not happy about the dose my dog was having as there was no change at all in the frequency of fits and as it happened he had a couple 12 hours apart, which may have been due to Pexion.
    My vet read from the veterinary drug handbook about Pexion and said in some cases the fits will INCREASE on Pexion, which is why he took my dog off of the drug.

    • Did your vet reduce the dose gradually, Kay, or just stop it? Some say it is safe to stop at any time and others recommend it is done gradually.

    • Thank you for the advice Kay, Daisy has been on 1200mg of Pexion for 13 days now, so far she has not had a fit but she has never gone more than 2 weeks without one, so I am expecting one very soon. Iam not gong to increase her dose any higher if she has another fit even though the vet will probably recommend it. I am going to insist that she tries another medication even though the vet says that other medications makes them drowsy and they have no quality of life!
      I was talking o someone yesterday who’s dog as epilepsy but the epilepsy is controlled by diet. He said that it is something about the protein in their diet, do you anything about his Kay?

      • Hi Wendy, I do wish you luck finding the right medication. I noticed that someone had mentioned protein in the diet. When Bronte first began having fits I got in touch with the Canine Epilepsy Support Group who advised me to change her food to the lowest protein food available and rotate it (Chappie, Butcher’s etc.) I also used Bach’s Rescue Remedy and gave her a supplement called Taurine. Bronte has never had any meds other than Pexion and I agreed to it because I was told it was a wonder drug with no side effects. I am not convinced and thinking of taking her off it. Link to Epilepsy Support is and my contact is Anne Morley at Good luck xx

      • What a worry for you Diane that your collie is having fits as he is so young. Please do try cutting out all processed dog food, that includes tins of food. I am now giving my dogs who are young, raw mashed vegetables twice a day(that includes ALL VEGETABLES AND MOST FRUIT ) raw bones every other day for their teeth and raw heart, liver, chicken legs and wings and any other raw steak I can get cheaply from the butcher. I am convinced it is todays dry processed dog food that predisposes to the increase of fits in our beloved animals. I have said so often on this blog that fits were never mentioned in dogs fifty years ago and indeed I had never heard of dogs having fits until my own beautiful border collie started having them a year ago. Now I have lost her and I do not want to lose my young collie who is just one. Please just give it a try anyway. There is so much on the net now about BARF feeding for pets. Its very easy and much cheaper than those bags of nuts that are all sprayed with some ghastly fat spray to make them more edible.

        All the best,


  3. Hi Val
    He decreased gradually, five days with one morning and night and five days with a half morning and night…
    He has not replaced it with anything though, no fits as of yet…. he used to have one fit approx. a fortnight. So since last Thursday no tablets of anything. Fingers crossed.

  4. Hi my border collie started fitting just after his first birthday which was a total shock for us as a family. Took him in overnight as it was a Sunday they took good care of him and put him on phenobarbital . Started him on a small dose but now has 60mg twise a day has cluster fits every three weeks. Spent more time in hospital as the fits were not controlled , now also has pexion 100mg twise a day. He went three weeks without any fits and then to the pattern had another cluster fits that lasted all day don’t know where to go from here

  5. I am sorry to hear about your dog Diane, I think it is trial and error with all drugs, drugs all have pros and cons. Has your vet mentioned potassium bromide? I think that you can use that with phenobarbital if your dog tolerates it. I will NOT put Ernie on phenobarbital – he came off all drugs 9 days ago and no fits yet….. his last fit was 12th July so he was due to have a fit a fortnight after that, so far so good. if I have to I might start on potassium bromide.
    Also if your dog is just one isn’t that unusual for it to be idiopathic epilepsy? I thought the fits normally start around the age of 2 for that? Has the vet talked about any other causes? Suggested an MRI scan?
    I think the raw diet my work for some. Ernie has a good dry dog food with no grains at all, but I would consider the raw if he has fits and they are not controlled by other drugs.
    Sorry Wendy I didn’t see the question you asked about protein. I haven’t heard of a link to protein. I will look at the link that Val b posted.

    • Hi Kay I’ve investigated that border collies if they have idiopathic epilepsy starts after there first birthday which is what happened to brody. He has been seen by the vrcc veterinary referrals cancer and critical care centre they have ruled out brain tumours or anything else other than what they have said he has. Thank you for your advice .

  6. I forgot to post this.

    people may have seen it but I was interested in this on that link….

    Pexion 100 mg and 400 mg tablets for dogs

    Contra-indications, warnings, etc

    Do not use in case of hypersensitivity to the active substance or to any of the excipients. Do not use in dogs with severely impaired hepatic function, severe renal or severe cardiovascular disorders.

    The pharmacological response to imepitoin may vary and efficacy may not be complete. Nevertheless imepitoin is considered to be a suitable treatment option in some dogs because of its safety profile. On treatment, some dogs will be free of seizures, in other dogs a reduction of the number of seizures will be observed, whilst others may be non-responders.
    In non-responders, an increase in seizure frequency may be observed.
    Should seizures not be adequately controlled, further diagnostic measures and other antiepileptic treatment should be considered.

    The benefit/risk assessment for the individual dog should take into account the details in the product literature.

    The efficacy of the veterinary medicinal product in dogs with status epilepticus and cluster seizures has not been investigated. Therefore, imepitoin should not be used as primary treatment in dogs with cluster seizures and status epilepticus. Transition to other types of antiepileptic therapy should be done gradually and with appropriate clinical supervision.

    No loss of anticonvulsant efficacy (tolerance development) during continuous treatment of 4 weeks was observed in experimental studies lasting 4 weeks.

  7. My bichon is 5 years old and recently started to have fits. He is now on Pexion 2 in the morning followed by 2 at night. They are defintly not working. Sometimes he is having four fits in two days. Then he may go 5 days without a fit.
    I feel that I can’t leave him alone in case he hurts himself.
    Please can you give me any advice?

    • Hi Niki
      I am sorry to hear about your dog.
      I can only advise talking to your vet about your experiences.
      If you think that your dog has become worse or is fitting more then perhaps ask if you could try another drug.
      You know your dog best, how he is acting on the tablets and whether he is worse or if there is no change.
      I hope things get better for you soon

  8. Well my Daisy managed to go 4 weeks and 1 day without a fit until Monday of this week where she had 8 fits in 24 hours. I rushed her to the vets because she was in a very bad way (hallucinating, stressed and not with it) now 3 days on she is still a bit nervous, has only just remembered who we are but the dog I know seems to be gone. I am hoping that it is a result of so many fits in such a short period of time and she will get back to normal. My vet has now agreed with me after 2 months of telling them that Pexion is not working! She is booked in for an MRI next week because my vet suspects that she has a brain tumour. I am hoping and praying that that is not the case and she is the way she is now because of so many fits in such a short period of time. Has anyone else experienced this with their dog?

    • Hi Wendy – yes, our own dog had the exact pattern that you describe. He was diagnosed with epilepsy in February and was seizure free for three months on Pexion. He had another small fit, but then had eight siezures close together a few weeks ago and was exactly as you describe. We rushed him to the vet and it took three days for him to settle again. He was staggering, crashing into things, falling over, etc but he did recover and was back to being bouncy, happy and enjoying life after three days. It is an ongoing process for us at the moment as all blood tests for thyroid problems etc are proving inconclusive and we are changing the medication. Fingers crossed here for you and dog.

      • Hi Sal, have you changed your dogs medication yet? I have had a long discussion today about changing Daisy’s medication. I have to start her tomorrow on epiphen and she is also going to give me kappra to keep in the house to give to her if she has cluster fits again. Daisy is still not 100% after nearly a week, she seems to have forgotten certain words and is not interested in the slightest about going for a walk whereas before the 8 fits she loved her walks. She is going on Thursday to vets just so that she can check her over, fingers crossed her problems at the minute are due to so many fits in such a short time, please let me know how you get on with the medication Sal, all the best of luck

  9. Hi daisy my border collie brody has been on pexion and phenobarbital for two months and totally agree with you that it does not seen to stop the fits. he had many fits all through the day and night which was Tuesday the 2nd of sept he still is not 100% now we are waiting to hear from our vet as they do not really know what to do with him he is only 17mouths x

  10. Every three to four weeks he has cluster fits x

    • Dear Dianne,
      My dog Izzy was put on pexion when it had been out a few months, she had her first fit at a year old and continued to have 3 or 4 fits every 3 weeks. My vet put her on epiphen initially and when that didn’t stop the siezures added Lebromide, she still continued to have seizures regular as clockwork. I took her down to Cambridge University to their Animal Hospital as Anne Van Haesenbrauk a top neurologist had studied canine epilepsy and I was so desperate to help my beautiful dog. They did a brain scan and drew fluid from the spinal column and found nothing so she was diagnosed with Idiopathic Epilepsy. We continued on the medication adjusting the doses but she still had regular fits until she had a really bad episode and we found that the bromide was not suitable and we nearly lost her t pancreatitus. It was at this time that pexion came out and I weaned Izzy off the Epiphen whilst starting with pexion. I had also changed her diet to BARF using mainly chicken inc bones and found other natural ways like Bachs rescue oil, skullcap & valerian tablets. Nothing worked and when she was just on the pexion we thought we’d cracked it as she went for 6 weeks nearly without a fit, and then she started having them weekly-every saturday and she had in excess of 30 seizures over the weekend, she spent the last 2 weekends at my vets heavily sedated with valium. After the first weekend I stopped the Pexion as suggested in the notes and wish I had put “The Valium Protocol” in place before stopping the Pexion. I believe to this day that if I had reduced the dose slowly it may have made things better for her as the withdrawal brought on the clusters that took her life. My vets could only sedate her to stop the fits temporarily and as soon as they brought her round the clusters continued- after so many (every 3/4 minutes) her temperature had risen to high and we don’t think she’d have been able to function like that, so the decision was made by us and my vet to put her down- she was only 3 and a half. If you look up the canine epilepsy guardian angels website, they have loads of information on there, most of the people have had an epileptic animal and are full of ideas that you may find helpful.
      I wish you all the luck in the world and hope you find something that works so you don’t have to go through the pain of losing your dog. My postings on this forum are exactly a year ago, from May/June to 2nd September hen Izzy was pts and no longer suffering. May the angels be with you.
      Love Amanda x

  11. Thank you Amanda I will defo look on their web site thank you for sharing your story x

    • I am so sorry that so many people are not having any luck with Pexion.

      Murphy is a 25kg labradoodle and has been on Pexion for just over a year now. He started out having 400mg twice a day and we’ve gradually had to increase this to 600mg twice a day, but ‘touch wood’ its working brilliantly for him. He doesn’t cluster fit, but as soon as he has a fit I administer rectal diazepam. There is no pattern at all to his fits, he has only had five so far this year, and hasn’t had once since mid-June.

      I really hope that other people on here do find something that works for their dog, its an awful, heart breaking disease.

  12. My 14 year old Bichon who has never had a fit all her life had several in one weekend a couple of weeks ago. We went to bed as usual one Friday night, only for me to be startled awake about 3 hours later by her distressed barking. She seemed to be having some sort of fit. She’d wet the bed and the episode lasted roughly about a minute. Of course being startled awake and seeing her like that scared the living daylights out of me. I phoned the vet who was on call that night and she agreed that it sounded like some sort of seizure and to take her to the surgery the following morning. After a very sleepless night and 7 and a half hours later she had another one- This one didn’t seem to last as long as the first one, but otherwise was exactly the same with the distressed barking, wetting herself etc. I phoned the vet again to tell her that she’d had a second episode then took her to the surgery and hour or so later after she’d come round a bit. The vet immediately started her on Pexion 100mg half a tablet twice daily because of her age and being quite frail. On examination she also had a bit of a temperature- nothing too drastic- but gave her a long acting antibiotic injection just to be safe. Saturday afternoon she perked up alot and seemed to be back to her usual self. Saturday night however was really bad. I gave her the second dose of Pexion later that evening and maybe an hour or so later I noticed she wasn’t herself again. Very heavy breathing and I started to get a bit worried again and never left her side. Low and behold nearly 14 hours after the second seizure she had that morning she had her third. I was alot calmer this time for my dogs sake rather than mine but was still very upset to see her like this when she’d perked up so much just hours earlier. Again the episode was exactly the same as the other two (distressed barking, wetting herself and it lasted about the same as the second one). Then about hour and a half later just as we’d settled down for bed she had a fourth. Although I remained calm for her I was now VERY concerned. Her breathing became very rapid. I should have phoned the vet but didn’t because I knew she would have got even more distressed if I had to take her to the surgery again and she needed to be admitted overnight. Instead I had her right next to me all night keeping contact as much as possible. The very rapid breathing went on nearly all night and she wet herself several times but there didn’t seem to be any seizure that I was aware of. Early the following morning (about 7.30am) she had another one and again it was the same as the others. That was just over a week ago (it will be 2 weeks next Sunday, 23rd Sept) and she hasn’t had anything since. I’m assuming it’s the Pexion that has stopped her from having anymore of these seizures and I will be continuing to give them to her. The main reason I have come to this page was to see if there were any side effects to this drug. My dog was drinking a little more than usual before starting Pexion, but now it’s increased even more. It’s not just her increased thirst either, but her appetite now as well. I don’t really want to stop giving this drug to her as I’d much rather her have increased thirst and hunger over seizures any day. Any feedback will be greatly appreciated. Before I go the vet seemed to think that these seizures were more likely to be age related rather than epilepsy as she’s an old girl now.

    • Hi Tracy,
      Glad to hear that your dog is better on Pexion – I can confirm that increased hunger and thirst are two of the side effects of Pexion. I hope she will continue to do well xx

      • Thank you so much for replying. Angel has gone what would have been 2 weeks today with no fit, but just now as I am writing this she is in my arms recovering from a very slight one. I just hope she’ll perk up later on now. It is now nearly 6am and I am up at this unearthly hour on a Sunday because Angel woke me up at about 4.30am desperate for a drink. I am kind of relieved to know that increased hunger and thirst are side effects, but Angels thirst seems a bit extreme. It’s not the first time she has woke me up during the early hours crying for a drink. And when I take her downstairs for one she is drinking solid for a good couple of minutes sometimes longer. She has had a load of blood tests done fairly recently- kidney function being one of them- and apart from that one being slightly abnormal everything was fine. I’m not sure though if they checked her glucose levels. I will be getting back in touch with the vet on Monday to check. I don’t really want her to be poked and prodded too much now that she is old and fragile as a trip to the vet really distresses her.
        The fit she had this morning now was different to the others. She wet herself the same as before and she also had that rapid like breathing. But there was no barking this time though. I don’t actually think I’d have noticed that she’d had one if I wasn’t awake and she was in her bed by my feet. Thank you again for replying. What do you think about her extreme thirst though. As I said in my first post, before she was put on Pexion her thirst had increased which I put down to the hot weather, but it has now sky rocketed.

        • Hi Tracy,
          I wouldn’t class my dog’s thirst or hunger are extreme, but both are certainly noticeably increased since being on Pexion. Also, her fits have changed on the drug – they have been fewer but of longer duration and much more pronounced. And instead of having the usual warning beforehand, she has simply collapsed in front of me and on another occasion discharged her anal glands, though she has not yet been incontinent in a fit. My vet agrees with me that anything regularly exceeding 4/5 minutes is dangerous, and Bronte’s last fit was of 10 minutes’ duration. It is for this reason that she is coming off the Pexion – so far been on half the dose for a month, now on a quarter for another week and then she will come off it altogether. The vet confirmed that it is not necessary to wean them off it gradually, but she wanted to see what happened, if anything, on a reduced dose. So far, the result is positive. My vet admits to being disappointed with Pexion’s performance after all the hype.
          It sounds as if you may need to visit your vet as you mention; would it be an idea to phone first and find out if they tested Angel’s blood glucose last time? Kidney health can be a concern in old age but it sounds as if that was reasonable at the time of her last test.
          I know how you feel; it is devastating to see them suffering at any time. I hope you can get some answers and that you and Angel can find some peace and rest. Try to stay positive – that won’t be easy – but if you can be as calm and relaxed as possible it will help you both.
          Good luck and lots of love xx

  13. I have 2 boxers reg and Harvey who are nearly 3 years old , last year reg started to have seizers , after lots of care and attention from my vet the fits were under control and reg was put onto Phenobarbital , he had one fit every 3-4 months ( I could cope with that ) but because stay on Phenobarbital can damage his liver my vet wanted to wean him off Phenobarbital and start using pexion , with days of starting pexion he was fitting he was having 10 to 15 fits a day , after seeing my emergency vet they stopped the pexion straight away , they said to carry on with the Phenobarbital and after a day of being off pexion he stopped having the fits , the vets are now going to try a differnt medication but I will never have him on pexion again . He is back to being very playful and loving .

    • Try adding a few drops of milk thistle tincture to his diet (in water) it helps protect dogs liver just like it does for humans.
      Obviously check with your vet first.
      Amanda x

      • Thank you for that Amdanda I vet had never mentioned this , reg is due back next week for his bloods so I will emotion it ty very much :) x

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