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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

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