Pexion for dogs



Active ingredient



Anti-seizure, behaviour

What is Pexion?

Pexion is a brand name for the anti-seizure drug called imepitoin. It comes as a tablet and is commonly used to treat epilepsy in dogs. Pexion is also given to dogs with a fear of certain sounds, such as fireworks. Pexion is a prescription-only medicine in the UK, so your vet will need to prescribe Pexion for your dog.

What does Pexion do?

Pexion contains the anti-seizure drug imepitoin and is mainly used to treat epilepsy in dogs. The main sign of epilepsy is seizures, which are caused by over-active nerves in the brain. Imepitoin works by calming these nerves down, therefore preventing seizures from happening. Imepitoin binds to and activates GABA channels in the same way as benzodiazapines such as diazapem. This reduces the nerve impulses, calming the nerves down. Unlike benzodiazapines, Pexion doesn’t become less effective over time.

Pexion also appears to help manage anxiety in dogs, especially noise phobia. The exact way Pexion does this is not fully understood, but it’s likely related to its GABA channel effects.

What is Pexion for?

Pexion is given to dogs for several reasons. Its main use is to control epilepsy in dogs.

Here are the common reasons why Pexion is recommended for pets:

  • Epilepsy
  • Anxiety, particularly due to a fear of certain noises
  • Other behavioural disorders
  • Neurological pain

Your vet may recommend Pexion for anxiety and fear due to other reasons. Pexion may also be given to reduce seizures in other neurological conditions, such as brain tumours or infections. There are several other less common situations where your vet may think that it is suitable to give Pexion, such as sleep disorders. Pexion may be given along with other drugs and lifestyle changes to help stabilise your dog’s condition. Remember, Pexion should always be given under veterinary guidance, ensure to consult your vet so that you can do what’s best for your pet.

What are the side effects of Pexion in dogs?

Whilst most pets tolerate Pexion without any issues, it can have side effects just like all other medications. The side effects of Pexion are usually mild and only last for a short time. Certain side effects may be more common depending on whether your pet is on Pexion for epilepsy or anxiety.

The common side effects of Pexion that you should be aware of include:

  • Lack of coordination – This side effect is very common in dogs being given Pexion for both epilepsy and anxiety, occurring in more than 1 in 10 dogs. This should resolve within 24-48 hours of starting the medication, even if the medication is continued.
  • Vomiting – This side effect is also common in dogs being given Pexion for both epilepsy and anxiety. It’s thought to affect more than 1 in 10 dogs
  • Diarrhoea – This side effect is more common in dogs being given Pexion for epilepsy.
  • Sleepiness – Affects more than 1 in 10 dogs.
  • Change in appetite – Excessive eating/hunger is another common side effect of Pexion and normally affects more than 1 in 10 dogs.
  • Aggression – This side effect is more common in dogs being given Pexion for anxiety but may happen in up to 10% of dogs receiving Pexion.
  • Increased urinating and drinking – This side effect is more common in dogs being given Pexion for epilepsy, and affects about 1-10% of dogs.
  • Hyperactiveness – This means your pet may be much more active than usual. This side effect is more common in dogs being given Pexion for epilepsy. It’s thought to affect about 1-10% of dogs getting Pexion.

There are some rare side effects to also be aware of, these include:

  • Prolapsed third eyelid – the third eyelid in the inner corner of the eye becomes more visible. This is from isolated reports only, with less than 1 in 10,000 dogs being affected.
  • Decreased sight – there are isolated reports of this, with less than 1 in 10,000 dogs being affected

Remember, the benefits of using Pexion usually outweigh these risks. However, if you do notice any of these side effects or are worried about a change in your pet’s behaviour, get in touch with your vet for more advice. Your vet should report the side effect, which may result in further investigation and a change to the package leaflet to keep other pets safe. They will also provide you with guidance and adjust the treatment plan if necessary.

Which pets is Pexion not suitable for?

Whilst Pexion is suitable for most pets, there are a few situations where Pexion should be avoided, and alternatives should be discussed with your vet.

  • Pexion is not suitable for dogs with severe heart, liver, or kidney disease.
  • Pexion is not suitable for dogs that are allergic to any of the ingredients in this product.
  • Pexion is not suitable for male breeding dogs.
  • Pexion is not suitable for pregnant or lactating dogs.
  • Pexion may not be suitable for dogs with a history of aggression due to an increase in aggression sometimes seen as a side effect. If your dog has a history of aggression, your vet may recommend a behaviourist assessment before starting therapy.
  • Pexion has not been tested for noise phobia in dogs younger than a year old.

How to give Pexion safely:

  1. Follow vet instructions: Always use Pexion exactly as your vet has prescribed. This includes the right dose and frequency. Never adjust the dose on your own, even if your dog seems to be feeling better or worse. If you aren’t sure of the dose prescribed, please call your vet to confirm.
  2. Tablet form: Pexion tablets can be given directly into your dog’s mouth or can be hidden in a piece of food such as a strawberry or some cream cheese. If you are struggling to give your dog their tablets, you should talk to your vet about your options.
  3. Give on an empty stomach: It’s best to give Pexion on an empty stomach, as more of the drug is absorbed. However, the most important thing is to be consistent about the timing of Pexion compared to feeding so that the same amount is absorbed each time.
  4. Monitor your pet for side effects: If you notice any side effects or are worried about your pet’s response to Pexion, contact your vet immediately.
  5. Do not abruptly stop Pexion: Suddenly stopping this medication can cause seizures to recur or withdrawal symptoms. Talk to your vet first if you want to stop giving your pet this medication.
  6. Check with your vet if giving anything else: Your vet should be aware of other drugs your pet is on, but it’s always worth double-checking in case there’s been a miscommunication somewhere. If your dog is on supplements or non-prescription treatments you should also tell your vet when they prescribe Pexion, as they may not be suitable to be given together. Some antibiotics, including metronidazole and chloramphenicol, should not be given with Pexion.
  7. Storage and Handling: Store Pexion in a cool and dry place, out of direct sunlight. Keep out of sight and reach of children. Do not use this product after the expiry date on the packaging. If accidental human ingestion occurs, seek medical advice immediately.
  8. Report any accidental overdose to your vet immediately: If you have mistakenly given too much Pexion, report it to your vet as soon as you realise the error. They may recommend monitoring to make sure everything is ok with your pet.

How much monitoring do pets need on Pexion?

  • High monitoring need


    Most pets will not require any special monitoring while on Pexion.

Pexion doesn’t require special tests, unlike other common epilepsy medicines for dogs. However, your vet will need to see your dog for check-ups in order to satisfy themselves that the drug is working and the dose is correct. These visits will be more frequent at first (perhaps a week after starting the medication or changing the dose, then again a month later), but once the dog is stable they can usually become less frequent, depending on your dog’s individual situation.

What does Pexion cost?

  • pound

    £££ – Expensive

    A month of Pexion costs £20-£180

Pexion tablets cost £0.40-2 each, depending on the dose (100mg tablets vs 400mg tablets) and where you get them from. Dogs will need 1-4 tablets a day (split into two doses 12 hours apart), unless they are not responding in which case the dose might be increased. Don’t forget to include the cost of prescriptions, postage, and dispensing fees when comparing Pexion prices.

Pexion FAQs

What is the generic name for Pexion?

The generic name for Pexion is imepitoin. This drug is used to help treat seizures in dogs, which could be due to epilepsy or another neurological condition. Imepitoin is also used to treat anxiety in dogs due to a fear of certain noises.

How long does it take Pexion to work for anxiety?

Typically, Pexion takes several days to weeks to work for anxiety. However, this may vary depending on your dog’s metabolism, the severity of their anxiety and the use of other medications and lifestyle changes. it’s normally recommended to start it at least two days before a known stressful event. If you think Pexion isn’t working or is taking too long to work, speak to your vet about what else could be done or the alternative medications on offer.

Can Pexion be given without food?

Pexion can be given without food, as more of the drug is absorbed this way. However, the most important thing is that the timing of the dose compared to feeding is consistent each day. Your vet will adjust the dose of Pexion depending on your dog’s response, so being consistent is important.

Can you split Pexion tablets?

Pexion tablets are half-scored, meaning you can split a tablet into halves. If you split a 100mg tablet, you will have created 2x 50mg tablets. Follow your vet’s instructions, they may need you to split the tablets depending on your dog’s weight and required dose of medication. If you are unsure about how to split the tablets, your vet will be happy to do this for you.

Half-tablets left after a dose should be used or discarded after 24 hours. For example, if your dog needs one and a half tablets twice a day, you should carefully and safely keep the remaining half-tablet for their next dose.

Pexion Alternatives

Your vet will be happy to discuss the next best alternative for your pet if:

  • They have had unwanted side effects.
  • Are allergic to Pexion.
  • Pexion doesn’t seem to be working.
  • You are struggling to give your dog their tablets.

Currently, tablets are the only form of imepitoin available for dogs in the UK. If you are struggling to get your pet to take their tablets, it may be a good idea to opt for a different drug that is available as an injection or liquid formulation so that it can be mixed with food more easily.  There are many other anti-seizure and anti-anxiety drugs available if Pexion is not working, along with alternative forms.

The alternative anti-seizure drugs and formulations include:

  • Phenobarbital e.g. Epiphen – available as a tablet.
  • Potassium bromide e.g. Libromide – available as a tablet.
  • Levetiracetam – available as a tablet, injection, or liquid.
  • Zonisamide – available as a tablet but can be made into a liquid suspension.
  • Diet – in some cases, diet changes can help to reduce seizures.

The alternative options for treating anxiety include:

  • Gabapentin – available as a tablet or liquid.
  • Sileo – available as an oral gel
  • Trazadone – available as a tablet
  • Alprazolam – available as a tablet or liquid.
  • SSRIs e.g. Prozac – available as a chewable tablet
  • TCAs e.g. Clomicalm – available as a tablet but can be made into a liquid suspension.
  • Natural supplements – Adaptil and Nutracalm

Whilst medications are useful in treating anxiety, behavioural modification is another important part of treating behavioural disorders, such as anxiety, and especially noise phobias. This may include a training process called ‘counter-conditioning’. Your vet will be able to give you more advice on this process and could even refer you to a specialist.

It is important to remember that you will not be able to buy any anti-seizure or behavioural medication for your pet over a non-veterinary counter! You will have to go back to your vet to discuss the other options, where you can both decide what is the next best thing for your pet to keep them happy and comfortable. Natural supplements, including Adaptil and Nutracalm, are the only exception to this.

Pexion Datasheet

All drugs have a manufacturer’s datasheet, which gives information about the drug’s use and possible side effects. There is usually one with your Pexion, but if you have lost it you can click on the button below to be taken on an online version.

Please note that the information contained herein is provided for informational purposes only. Although it has been written by a vet, we cannot consider the individual nature of your pet’s problems so it does not constitute veterinary advice. If you have questions about your pet’s medication or their health you should contact a vet, who will be able to help.