Canine Seizures

The onset of a dog’s seizures can be terrifying for his family. Take a breath, though – they are treatable.


Seizures are not common in dogs – but they aren’t rare, either. The Veterinary Information Network estimates that the prevalence in the dog population is about 1%. While distressing to witness, they are rarely life-threatening. After you’ve gotten past the shock of the event and your dog is coming out of the seizure, your mind will be racing. What caused the seizure in the first place? Does your dog have epilepsy? Is this going to happen again? Turns out, these are not always easy questions to answer. 

“Epilepsy” refers to a seizure disorder in which all other possible causes have been eliminated; it is a diagnosis of exclusion. The seizures seem to occur spontaneously, with no underlying structural brain disease or metabolic illness. This means that there is no test that will identify epilepsy. Rather, all other causes must be ruled out before this diagnosis can be made. Doing this can be an extensive and pricey process.

Certain breeds are predisposed to epilepsy, including Beagles, Poodles, Boxers, Labrador Retrievers, Golden Retrievers, Border Collies, and Shelties. While the disease may have genetic roots, it can also occur spontaneously in any dog. 

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Seizures occur when neurons in the brain rapidly discharge over and over again. Gamma aminobutyric acid (GABA) is a neurotransmitter in the brain that inhibits excitation of neurons, and in a seizure, the GABA receptor system is particularly involved. When seizures occur, normal GABA inhibition is overcome, and the brain cannot “calm down.” The increased electrical activity leads to changes in behavior, which can manifest in many different ways. 

The classic seizure type, once called grand mal, is now referred to as tonic-clonic; tonic refers to the stiffening of the dog’s muscles and clonic refers to the dog’s twitching or jerking. Strong muscle contractions occur, the dog is unable to stand, and may lose bowel and bladder control. The dog may also vocalize. 

The hallmark of a true seizure is the post-ictal period. Once the muscle contraction ceases and the seizure is over, a dog will take some time (from minutes to hours) to return to normal. In some cases, blindness and disorientation can persist for a day or more. Behavior may be very strange, such as a complete disinterest in food or ravenous eating. Difficulty walking may also occur. Your dog may sleep deeply or be restless. 

Other seizure types include focal seizures (also called petit mal), in which only one part of the body is involved (such as the face); the muscles in that area may twitch or contract. In absence spells, during which a dog is conscious but not responding, the eyes may be open, but he may not answer when his name is called or he is touched. These types of seizures may presage tonic-clonic and can go unnoticed, because they are often subtle. 

In most cases, these electrical discharges are self-limiting, meaning the seizure will cease on its own. In occasional cases, the seizure does not end, leading to a condition called status epilepticus (see sidebar, page 7). 


To reach a diagnosis of epilepsy, a thorough work-up will be necessary. At the initial examination, your veterinarian will gather a history. 

Be prepared to answer questions about the duration and severity of any seizures you have witnessed, as well as any precipitating events that you noticed, such as stress, excitement, or sleeping. Toxins or medications in the house are also an important piece of the puzzle. While seizures are distressing to see, getting a video for your veterinarian could help with the diagnosis. Once your dog is in a safe position, try to record the event.

After history-taking, your veterinarian will examine your dog. This nose-to-tail exam will help identify any abnormalities that may point toward a diagnosis. Once completed, the diagnostics start. 

Initially, a “minimum database” of diagnostic tests is recommended. This includes a complete blood count (CBC), chemistry panel, and urinalysis. Depending on your dog’s age, a blood pressure measurement and x-rays may also be recommended. These will identify underlying metabolic causes that can lead to seizures, such as extremely high blood sugar (as in diabetic ketoacidosis) or kidney failure related to antifreeze ingestion. 


The cause of seizures can be broken down loosely into age groups:

Puppies younger than 6 months.

It is uncommon for a dog to develop true epilepsy before six months of age. In dogs this young, other causes are much more likely. These can include everything from parasitic infection with protozoa such as Neospora species, to viruses such as canine distemper virus, to toxin exposure (a common problem in curious puppies).

A thorough work-up for a puppy with seizures will include the minimum database above, as well as recommendations for the following (depending on breed and history):

  • Bile acid test. This is done if a liver shunt is suspected. Liver shunts are abnormal blood vessels that interfere with proper metabolism by the liver. When present, they can cause seizures and abnormal behavior, especially after meals. Yorkshire Terriers, Maltese, Bichon Frises, and Miniature Poodles are all predisposed. 
  • Titers for infectious disease. Canine distemper virus (CDV), the fungi Cryptococcus and Coccidioides, and protozoal diseases such as neospora and toxoplasma can all cause seizure activity.
  • Computed Tomography (CT) scan or magnetic resonance imaging (MRI). These tools for imaging the brain can determine whether structural abnormalities like hydrocephalus (a condition where cerebrospinal fluid builds up in a dog’s skull) or Chiari malformation (structural defects in the base of the skull and cerebellum, the part of the brain that controls balance)are present. 
  • Cerebrospinal tap. This can help identify meningitis, as seen with inflammation or infection.Work-ups can be expensive and time intensive, so many owners opt to treat with medications and wait to see how the dog responds. With puppies, though, epilepsy is an unlikely cause, which means another disease may be at work and will likely progress and worsen.In puppies, it is also imperative to rule out exposure to toxins. Puppies are naturally inquisitive, and this often leads to accidental exposure to medications, cleaning products, and even illicit drugs. 

Dogs 6 months to 5 years.

At this age, an absence of other clinical symptoms or known toxin exposure makes epilepsy the most common cause. This is especially true in predisposed breeds. As a result, once the minimum database has been completed and obvious causes such as toxins ruled out, many owners opt to treat with anti-seizure medications and see how a patient responds. 

Dogs older than 5 or 6 years.

In dogs older than 5 years, the most common cause of acute onset of seizures is generally a brain lesion, particularly brain tumors (masses). These are usually benign meningiomas, which can cause problems due to pressure on adjacent structures. 

The recommended diagnostics are similar to other age groups, starting with the minimum database. In this group, though, it’s also important to rule out hypertension (by checking blood pressure) and undetected cancer (by taking chest and abdominal x-rays) as possible causes. 


The treatment for seizures is evolving. First-line therapy remains drug management. These medications are referred to as anti-epileptic drugs (AEDs). Phenobarbital and potassium bromide have long been the drugs of choice, but other medications are now becoming popular. These include Keppra (levetiracetam) and Zonegran (zonisamide). 

Phenobarbital has been used in the management of human seizures for many years. It is reliable, effective, and relatively cheap. However, phenobarbital is a controlled medication and should be handled with care. It must always be stored away from children. 

Phenobarbital works on the dog’s GABA receptors, helping to inhibit the excitation of neurons. 

Phenobarbital does have significant side effects. It can cause ravenous appetite, weight gain, increased drinking and urinating, and induction of liver enzymes. In rare cases, it can cause liver failure. As a result, liver values should be monitored closely (at least every six months) by your veterinarian. If liver enzyme elevations occur, a newer seizure medication may be recommended. 

The dosage of phenobarbital must be individualized, so monitoring the dog’s phenobarbital levels is critical. This is usually initiated about two weeks after starting the medication, when it is expected to reach “steady state” levels. (A drug is at a steady state when the intake of the drug is at an equilibrium with its elimination.) At therapeutic levels, it can cause sedation and ataxia. Usually, dogs will acclimate to this over time. 

About 85 to 90% of dogs will experience a significant reduction in seizure activity with phenobarbital. 

Potassium bromide is also considered a first-line treatment, although this is shifting. Potassium bromide has many of the same side effects of phenobarbital and must also be monitored, as toxicity is possible. It can take up to four months for this medication to reach steady state levels. 

Diet is an important part of therapy with potassium bromide. Food with higher levels of sodium can increase the excretion of potassium bromide, leading to lower levels and increased seizure activity. The dog’s diet must be consistent while on this medication. 

Levetiracetam is being used more frequently to treat seizures. Initially, it was used in humans, and its use has been extrapolated to dogs. Its mechanism of action is not well understood, but it may affect the release of neurotransmitters. It is minimally metabolized by the liver, so it doesn’t cause the liver enzyme elevations that are seen with phenobarbital. Levetiracetam levels in the blood are therapeutic within about 24 to 36 hours (versus two weeks for phenobarbital). 

Levetiracetam also does not cause ravenous appetite and weight gain. It is considered so safe that regular monitoring is not usually necessary. It is important to note that two formulations are available and each must be given in different ways. “Regular” Keppra must be given every eight hours; Keppra-XR, an extended release formulation, can be given every 12 hours but cannot be crushed and placed in food (doing so would thwart the mechanisms that cause the drug to be released continuously over a 12-hour period). 

At 6 years old, after being stable on AEDs for several years, Bixby experienced status epilepticus. It took many medications over a full 24-hour period to stop his seizures. After two weeks of dedicated care from his vet and owner, he recovered fully.

Zonisamide does not act as quickly as Keppra but is faster than phenobarbital (about one week to reach steady state). Like Keppra, zonisamide generally has minimal effects on the liver. It does, however, have some rare side effects such as hepatopathy (liver congestion), dry eye, bladder stones, and hypothyroidism. Regular bloodwork monitoring is generally not necessary, but any changes in a dog’s condition should always be brought to the attention of your veterinarian. 

Unfortunately, medications are often a life-long necessity. Working closely with your veterinarian to taper to the lowest dose possible for management is the best approach. 


Products containing CBD (cannabidiol, a phytochemical compound extracted from cannabis plants) are becoming popular with owners as an adjunctive therapy for many illnesses. It is important to know that currently, other than in a handful of states, veterinarians are not allowed to recommend or discuss CBD as a treatment (see “Know Your CBDs,” WDJ August 2019).

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A study published in the Journal of the American Veterinary Medical Association (“Randomized blinded controlled clinical trial to assess the effect of oral cannabidiol administration in addition to conventional anti-epileptic treatment on seizure frequency in dogs with intractable idiopathic epilepsy,” June 1, 2019) evaluated CBD as an additional treatment in patients with intractable seizures. 

While the use of CBD was associated with a significant decrease in seizure activity, further investigation is warranted before therapeutic recommendations can be made. As laws change, your veterinarian may be able to discuss this with you. Use caution when choosing to administer CBD products without veterinary supervision, as neither the side effects nor interactions with other, FDA-approved medications are well understood. 

In 2015, a study supported the use of medium chain triglycerides (MCT) as a dietary supplement to decrease seizures. The diet studied was ketogenic (high fat, low proteins and carbohydrates). There are a few commercial diets available that address this need and may be helpful in managing seizures. 

Nutritional supplements such as omega-3 fatty acids, thiamine (vitamin B1), vitamin E, and s-adenosyl methionine with milk thistle may also have some benefit when used in conjunction with standard Debra Canapp treatment. Much of the knowledge we have in veterinary medicine about these supplements is extrapolated from human medical studies and anecdotal. However, the supplements are unlikely to cause harm. As always, consult with your veterinarian before adding any supplements to current treatments. 

Lastly, several studies have demonstrated possible benefit with the use of acupuncture. The exact reason acupuncture may help lower seizure frequency is not understood. The theory is that acupuncture stimulates the release of inhibitory neurotransmitters, therefore “calming” the brain. While it is not typically first-line treatment, in patients with intractable seizures or those with poor response to medications, it is another modality that may offer some relief. 

After nine years in emergency medicine, Catherine Ashe, DVM, now works as a relief veterinarian in Asheville, NC, and loves the GP side of medicine. 



  1. Also useful is Melatonin. I had a collie who developed seizures around her 6th birthday. They would often happen in her sleep. After I started giving her about 5mg of Melatonin at night, her seizures decreased significantly…when I added CBD to her protocol…they stopped completely.

    • Did your vet tell you about the Melatonin? The CBD is the oil? How did you know the amounts to give? My daughter and I each have one Chihuahua around 11 years old that gets them. Mine has been having seizures since around 2014. The vet put her on phenobarbital but she still has them. She may go weeks without one and then she may have them once or twice a day.

      • My 14 lb dog got seizures & the 3 diff meds caused him abdominal gas pain every time he ate, & lost rear leg function, & wasnt himself anymore. ER Vets couldn’t figure it out & added pepcid ac & baby gas drops which neither helped. Frustrated , did my own research & found CBD oil, a good quality one for dogs, which got him off ALL the meds & seizure free & able to walk again. Added Keto diet, no more unnecessary vaccines, or heartworm meds with pesticides in them. Vets dont have all the answers.

  2. Our beloved intact adopted Indian Spitz, Bunna gets them. We make it smell a concoction via each nostril for 3-4 seconds made by its esteemed veterinary surgeon, Dr Agnivesh Sharma, Daksh Pet Clinic, Gomti Nagar, Lucknow, India, to smell on which Bunna comes to normal in a jiffy. It is then started Viusid immunobooster 2-3mL once a day for 7 days. It does not drink milk but has plain curd in summer and fresh paneer (cottage cheese) in the evening.
    Former owners had acquired it when it was just 4-5 days old instead of the mandatory period of 45-60 days of being with its mother & siblings. That could be a reason.

  3. We had an Irish Wolfhound who had seizures. The first time he had one, I was convinced he was dying. It was just so frightening. With medication, his seizures were fairly well controlled. On medication, he’d have two or three seizures per year (and we always had rectal valium on hand to be safe–luckily, we never needed it). He knew when he was going to have one and he’d let us know, so we were able to get him lying down in a safe and comfortable area before the seizure hit. We stayed with him throughout the seizure and afterwards (be careful–don’t get fingers near the dog’s mouth when the seizure is in full force–they may bite you and it will NOT be their fault; and some dogs will be “out of it” for a few minutes after the seizure has passed and don’t want to be petted and my be grumpy–our guy wanted us there and wanted the comfort and petting). For most dogs, treatment is possible and most seizure dogs can live a relatively normal life.

    • Wow, that’s incredible that he could tell you he was going to have one!! Mine usually has them in his sleep or is at least quietly at rest. He’ll be resting or sleeping and then suddenly he’ll pop his head up, started sniffing around him and then I know it’s on.

  4. My Sheltie, Gretchen, developed epilepsy at a young age. Her seizures were dreadful, but after getting her on the correct dosage of Zonisamide, she never had another seizure. She experienced no side effects from the drug. It’s a great treatment option.

  5. My dog has been successfully treated for seizures using a drug we obtain in France called Pexion (or Imépitoïne), which is not available or even being tested for FDA approval as far I know.
    We were lucky enough to happen upon this medicine when the steroids prescribed by his American vet were causing him side effects that were worse than the seizure themselves during a month-long stay in France. We brought him to the French vet, who was surprised to hear that the American vet had not recommended Pexion, as it is a seizure medication developed specifically for dogs and not for humans. He had been under the impression that the drug was American, when in fact I believe it was developed in England.

    In any case, the results were immediate and astounding, and Gouvy has been taking the medicine ever since. I have been making the trip to France each year to stock up.

  6. My companion is a Bernese Mt Dog. Age 8 he started “seizure snapping” a slight brain response. My holistic vet suggested Choline 650 mg. and L-Lysine 500 mg. both just B vitamins. My baby is about 90 lbs. he is a love.
    For past two plus years this has almost stopped all seizures. He only takes 650 mg of Choline now. Safe vitamin no drugs no more issues. Again he is 90 lbs. so cut in half for smaller dogs would be my guess. Check with your vet as I did.

  7. My now almost 9 year old husky started with seizures at age 5. CBD (do your research and find a good company), Passion flower tincture, skullcap tincture, milk thistle, choline and occasionally valerian, seizures have greatly reduced. Longest stretch has been one year with none. Had one recently and I believe it is because I tried a different brand CBD. Back to my original brand.

  8. My 7-yr-old Pembroke Welsh Corgi suddenly had a serious grand mal seizure right in front of me one evening, 2 1/2 yrs ago. He was rushed to the ER which did – exactly nothing. There was reason to suspect he’d had one early that morning, but I didn’t know at the time. The next day he had another, shorter one. I took him immediately to our local vet who started him on Phenobarbital, and sought a consultation w a veterinary neurologist. The Phenobarbital had adverse effects on my dog – he couldn’t even summon the strength to jump up on my lap – and his neurologist was sufficiently concerned about the metabolic effects of the drug that she switched him to Levetiracetam (Keppra). He was also on immunosuppressant doses of prednisone, and THAT is not fun. He had an MRI to determine the nature/extent of his brain inflammation, and a spinal tap to r/o any organic or pathological cause. Diagnosis – idiopathic meningoencephalitis. Happily, he has had no further seizures and after 2 1/2 yrs is completely off all medications. His neurologist said he was VERY lucky.

  9. Not all stories end happily. Our 2 1/2 year old Irish setter suddenly started seizing, always in the middle of the night several times in a row. After a visit to the emergency vet, we were in regular contact with a veterinarian neurologist. Epilepsy was the final diagnosis. We tried EVERY medication mentioned above, various dosages, various combinations. We tried diets, you name it. This poor dog was at one point on 17 pills a day and still had numerous seizures. The side effects changed his personality, he went from a total sweetheart to a dog that growled and snapped at us. We finally weened him off the medications (on the adVise of the neurologist). Tried an all meat diet. He was pretty good for a couple of weeks and then suddenly started seizing every night. After A couple of days of this (we think) he had a stroke. Did not know us, did not know his own name. Didn’t know where he was. We finally had to put him down. I’m still not quite over the fact I had to put down a 3 year old pup.

  10. For Linda,
    I have an Irish terrier who began having seizures Days after her first and only rabies vaccine at the age of eight months. She was having grand mal seizures. Over the past five years she has done well on home cooked or other dog foods that contain no added vitamin/minerals. Even the best dog foods generally use a vitamin mineral pack that is sourced from China. Of course if they are not food-based they are all chemicals. That’s not always a bad thing, but when they come from China it is. I do home-cooked stew and add a vitamin mineral combo formulated by a vet at That alone made a difference but my girl was still having seizures a couple of times a month. About a year ago I tried CBD oil, and the dog has not had a seizure since then. I researched how much to give and how the best CBD oil is made. If you go to 4Corners Cannabis and look at their Pet Tincture, they have a lot of information as to how you can determine what dosage to start your dog with and how to administer it. My dog is 14 pounds, I got the 500 mg/ml and The beginning dose was two drops twice daily. She has stayed on that dosage for the past year. Nothing else in her diet or environment has changed. (I would like to add that it’s important also to not use flea and tick prevention products that can cause neurological damage. For my dog I use Insect Shield clothing and Ticked! both with 100% success in Northern Virginia which is heavily infested with ticks.) another good source of information on CBD oil and health and wellness advice is Dogs Naturally. All the best to you and your fur babies

    • What did you do for the pulmonary hypertension? We have a 13 yo cattle dog who “potentially has heart issues or possibly neurological issues resulting from spinal inflammation ”. Without anesthetizing her and performing some pretty extensive and invasive tests (risky because of the “potential heart issues and age” there is no definitive diagnosis. What happens, usually following a very busy and active day on the farm, is that occasionally she goes to stand up and it appears that her hind legs “go out” and she cannot and scrambles a bit. She then stiffens and falls flat onto her side, eyes are fixed for seconds, she loses control of her bladder, comes to and stands up like nothing happens moments later. I don’t see a major pattern except if she does too much during the day. I try to stave it off with T Relief (homeopathic) or a small amount of Prevacox. Anyone have any thoughts?

      • My daughter has a 14 year old maltese with an enlarged heart for which she is on meds. She also has seizures(syncope). Noticed she would get these if excited or wanting to play with another dog. Vet explained to us as she would get excited or breathing heavier the blood would not get to her brain fast enough there for she would have syncope. We keep her quieter, no playing or when we come in the door we pick her up in order to keep excitement to a minimum. Seems to help. I hope maybe this info will help you.

  11. The article addresses GABA-related seizures admirably. However, if your dog is having seizures, also have his blood sugar level tested, and re-tested.. Insulinoma – a tumor on the pancreas – is also a source of seizures. Very few vets have this on their radar. My beloved Pilgrim had an insulinoma that went undiagnosed for a year. A yorkie-poo, he was too small for surgery anyway; but once we knew, we kept honey and other doggie nutritional products with sugar that brought him out of the seizures.

    I take cbd oil myself for benign essential tremors and it is very effective. I loathe phenobarbitol and I don’t need it with cbd. I would definitely try it for doggie seizures. Laws are loosening up, and the health benefits should be discussed.

  12. My 9 y/o began having seizures & er vet gave him keppra, 2 more seizures at home they added Phenobarbital, then 2 more seizures, they added gabapentin, which after adding he couldn’t use his rear legs & also began having painful abdominal gas, they said give him pepcid ac & baby gas drops. The last 2 did nothing & the gas was after eating. Vet said try science diet (didnt know about all the dogs that died from it). Nothing worked. Very frustrated, & tired of vets ‘practicing’ on my pup, I researched. Found CBD Oil & a holistic group for pets on FB. Weaned him off crappy meds while using recommended CBD oil, off SD food, began using keto diet (turkey). Detoxed him w homemade green juice. I got my pup back, & i slowly helped him walk again. Dont give up on ur pup. Vets dont have all the answers. Im a CBD oil & Holistic believer now.

  13. Don’t forget that low thyroid levels are pretty common and can cause seizures when they get low enough. Many years ago one of my dogs had seizures shortly after a local-lab thyroid test showed her levels as normal. After checking everything else, my vet submitted to another lab. The first results were incorrect. As soon as we started her on l-thyroxine, she was seizure-less for the rest of her 16+ years.

    Nowadays I only have complete thyroid levels run through Hemopet.