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Phenobarbital for Dogs: A Definitive Guide

Your four-legged family member means the world to you. Trust us, we get it. At Honest Paws, we are all pet owners and animal lovers. Therefore, we know first hand how impossibly challenging it can be when something is wrong with (wo)man's best friend. Even worse, is having to experience it right before your eyes and knowing that there is very little you can do. We're talking about seizures.

The first time your dog experiences a convulsion will undoubtedly be an incredibly difficult thing to experience. However, once it's over, the reality of the situation must be addressed. What to do now? There are several extremely important things to know about dog seizures and the associated medication used to treat them. Being armed with knowledge about the potential risks involved is imperative before beginning treatment.

In this article, we'll cover a popular medication used to treat seizures and epilepsy called Phenobarbital. The realities of the drug may surprise you and will likely force you to reconsider whether the risks are worth the reward. We will also explore alternatives to the drug and ways that you can ensure Fido lives a long and happy life, regardless of their epilepsy diagnosis. Let's begin.

phenobarbital for dogs 

Understanding Dog Seizures

Before we jump into discussing all there is to know about Phenobarbital, it is important to understand your dog's disorder. Studies show that up to 5% of all dogs suffer from seizures, yet so many owners don't completely know what having an epileptic dog entails.

So what exactly are seizures? Seizures are medically defined as an uncontrolled electrical activity that occurs in the brain. This electrical activity typically produces a physical convulsion (also referred to as a fit), thought disturbances, secondary physical signs, or a combination of symptoms. Seizures are also often described as short-term derangements of normal cognitive function.

Epilepsy is a term used to describe repeated episodes of seizures.

What Causes Seizures in Dogs

When it comes to seizures, many pet parents wonder how they could have prevented the condition from developing in the first place. Was it something they could have stopped? The truth is, the majority of seizure disorders are referred to idiopathic epilepsy. An inherited condition, idiopathic epilepsy is one in which experts are still unsure of the exact cause and origin.

In other cases, seizures may develop due to the following conditions:

  • Liver disease
  • Kidney failure
  • Brain trauma
  • Brain tumor
  • Anemia
  • Low or high blood sugar
  • Electrolyte problems
  • Stoke
  • Toxins (such as poisoning)

Breeds Prone to Seizures

While seizures can occur in any dog, certain breeds are at a higher risk of the disorder.

These breeds include:

  • Beagle
  • Golden Retriever
  • Labrador Retriever
  • Shetland Sheepdog
  • Vizsla
  • Keeshond
  • Belgian Tervuren

It is extremely important for pet owners to be aware of risks associated with their dog's specific breed. For instance, Great Danes are at higher risks of heart disease and Boston Terriers are more prone to developing glaucoma. Knowing whether or not your dog is at a higher risk of any disorder will ensure that you know the beginning signs of development and can help prevent it from worsening.

What To Do For An Epileptic Dog

When your dog is experiencing a seizure, one of the most important things that you can do is make their surroundings as calm and quiet as you possibly can. Seizures do not cause the dog any pain, but loud noises and bright lights can cause the seizure to worsen as well as cause additional episodes to occur. Additionally, stress can also cause subsequent seizures to occur.

We also want to mention that as your dog's seizure can be frightening for you to watch, it is equally as troubling for other pets in the house. It is important to make sure that any other pets are kept away from the animal experiencing the seizure as additional barking can stress the dog out and cause more seizures to occur.

What is Phenobarbital for Dogs

Now, let's get back on track: Phenobarbital for dogs.

Phenobarbital for dogs is one of the most commonly prescribed medications to control the severity and frequency of seizures and epilepsy. The drug is also known as commonly known as Luminal or Barbita. Phenobarbital can either be used alone or in conjunction with other drugs to better treat epilepsy in dogs and is used in either capsule, tablet, oral liquid, or injectable form.

What is Potassium Bromide

Potassium Bromide is another commonly prescribed drug that aims to reduce the severity and frequency of seizures. Often times, veterinarians will prescribe both Potassium Bromide and Phenobarbital to be used together. In other cases, particularly in dogs who have a drug-resistance or in those who do not react will to Phenobarbital, Potassium Bromide will be prescribed as a replacement.

phenobarbital for dogs vs potassium bromide for dogs

Understanding How Phenobarbital for Dogs Works

A seizure occurs due to an unexpected surge in neuron activity in the brain. Phenobarbital works to minimize the severity and frequency of seizures by stabilizing and decreasing neuron activity within the brain. The drug also decreases the neurotransmitter (known as Glutamate), which is responsible for nerve stimulation.

Phenobarbital Uses

Many conventional drugs serve a wide array of purposes and treat varying diseases all with the same pill. Phenobarbital, however, is primarily only used to treat seizures and epilepsy. In some (relatively) uncommon cases, Phenobarbital may be used as a sedative.

Dosage Of Phenobarbital For Dogs

The appropriate dosage of Phenobarbital will significantly vary among different breeds of dogs. It is imperative that your veterinarian decides on the accurate dose after considering your dog's weight, the severity of the seizures, and how often they occur.

In most cases, your vet will direct you to administer Phenobarbital every 12 hours. Typically, the starting dose of Phenobarbital for dogs is 1 to 2 mg per pound of bodyweight.  With all drugs, but particularly with Phenobarbital, it is extremely important that you do not miss a dose as it can cause your dog to have a severe seizure episode. If for any reason you do miss a dose, never (bold) double up on the next dose. Give your dog the missed dose as soon as possible and then carry on with the usual routine of another dose every 12 hours.

Phenobarbital Precautions

Before we get into the side effects associated with Phenobarbital, there are a number of dogs who shouldn't be taking it in the first place. It is imperative that your veterinarian knows absolutely everything when it comes to your dog's health in order to know whether or not Phenobarbital is an appropriate medication.

Dogs Who Should NOT Take Phenobarbital

If your dog has any of the following health conditions, they should not take Phenobarbital:

Additionally, dogs currently taking the following medications should not take Phenobarbital as it is known to have counteractions:

  • Antihistamines
  • Anticoagulants
  • Beta-adrenergic blocker
  • Corticosteroids
  • Diazepam (along with other central nervous system depressants)
  • Doxycycline
  • Furosemide
  • Griseofulvin
  • Metronidazole
  • Rifampin
  • Theophylline
  • Valproic acid
  • Phenytoin sodium
  • Opiate agonists
  • Phenothiazine
  • Aminophylline
  • Chloramphenicol
  • Quinidine

Phenobarbital Side Effects in Dogs

The aforementioned precautions associated with Phenobarbital are enough to make anyone's head spin. However, they aren't the only concerns associated with the drug. The following are the common side effects of Phenobarbital for dogs.

Excessive Hunger & Weight Gain

A side effect of Phenobarbital for dogs that many pet parents have found is excessive hunger. Subsequently, all of the extra food intake can often lead to weight gain, particularly if the medication also alters their normal amount of activity.

phenobarbital for dogs can cause weight gain

Excessive Thirst & Urination

Another common side effect of Phenobarbital is excessive thirst and therefore an increased need to go to the bathroom. If you notice that your pup is frequently needing water bowl refills, it's likely a side effect of the medication.


Phenobarbital can also cause your dog to feel high levels of anxiety and uneasiness. As we touched on, anxiety is the enemy of dogs suffering from seizures and epilepsy as it can cause their seizures to worsen and occur more often.


The medication can also cause the dog to lose coordination in the hind limbs as well as experience bouts of weakness which inhibit their ability to move freely.


Like people, dogs can also experience bouts of depression. If you notice your dog sleeping more than usual or appearing down in the dumps, the medication may be at fault.


Similar to the symptoms of depression, the medication can also cause the dog to be very lethargic and appear to have no interest in things they once enjoyed


Conversely, while some dogs experience high levels of lethargy, some experience the exact opposite: hyperexcitability. If you find your dog pacing nonstop, acting restless, panting without reason, or being especially vocal, it's likely a side effect of Phenobarbital.

Excessive Vomiting

We have discussed that the long-term use of Phenobarbital has been directly linked to liver damage. If your dog is excessively vomiting, it may be a sign that they are experiencing liver problems. Excessive vomiting can also lead to issues like dehydration and inflammation and should be addressed by your vet in a timely manner.

Sudden and Severe Weight Loss

Related to excessive vomiting is sudden weight loss. Sudden and severe weight loss is directly linked to liver damage and must be addressed by your veterinarian right away.


Another telltale sign that the liver function is not performing well is when you can noticeably see a yellowing of the whites of the eyes and skin (also known as jaundice). Pet parents who have dogs on Phenobarbital must be implicitly aware of this side effect and act immediately if symptoms arise.

Changes in Urine

If you notice that your dog's urine is very dark and has a very strong smell, veterinary intervention is mandatory. These changes in urine are often signs of liver damage.

Changes in Stool

Additionally, dogs who are experiencing liver failure will often have weird colored fecal matter such as gray or mustard in color. Again, pet owners must be aware of these side effects in order to recognize them and act accordingly.


Lastly, in rare cases, Phenobarbital has caused anemia to develop. If for any reason you feel that the medication has caused the development of another disease, contact your vet.

Lessening the Side Effects of Phenobarbital

As you can see, the side effects of Phenobarbital can be pretty horrific. Therefore, minimizing any side effects that you can is paramount for your dog's health and wellbeing. The best way to do this is to ensure that your vet prescribes the lowest viable dose possible.

Additionally, it is beyond important for pet owners to have a heightened awareness of the aforementioned side effects. Recognizing a side effect when it first appears and acting appropriately is key to preventing irreversible damage.

Anti Seizure Medication Produces Additional Seizures

Unfortunately, you read that correctly. A major cause of seizures in dogs is the build-up of chemicals and toxicity in the body. The long-term use of anti-seizure medications floods the body with more toxins than it is able to flush out. On top of that, once the kidney and liver become damaged, even less toxins are able to be passed through the body. This inevitably causes a build-up of toxicity which in turn leads to more seizures.

On the other end, stopping the anti-seizure medication can also lead to the development of additional seizures, some which can be life-threatening. For this reason, it is imperative that dog owners understand the risks involved with beginning an anticonvulsant medication.

phenobarbital for dogs is best avoided

Alternatives for Phenobarbital for Dogs

Now, there are thankfully new conventional drugs as well as all natural alternatives for Phenobarbital for dogs. Before we dive into the options available, we want to stress that by no means are we trying to negate the need for conventional medicine. Some dogs in specific circumstances need Phenobarbital and we know that to be true. However, the medication is being prescribed at an exorbitant rate, many times to pet owners who do not fully understand the risk. The information we just discussed is not to scare you, but to make sure you are informed before making a decision.

Levetiracetam for Dogs | Keppra For Dogs

Levetiracetam (Keppra) is a newer anticonvulsant medication that is now being prescribed to epileptic dogs. Keppra can be used alone or in conjunction with other anticonvulsant drugs. Many pet owners are eager to try the new medication as it allows for a decreased dosage of Phenobarbital and therefore a decreased amount of adverse effects. However, there are still certain risks and potential adverse effects associated with Keppra for dogs including drowsiness, lethargy, behavioral changes, and gastrointestinal upset. 

The Power of Food

Additionally, we want to make sure that our readers never overlook the immense power that diet can have. For centuries and centuries, food has been used to cure and prevent a number of ailments. While science has certainly progressed, the fact of the matter is, food is still some of the best medicine available. Countless studies prove that a specifically formulated diet can be an absolute game-changer for an epileptic dog. Many experts advocate for a ketogenic diet, or one that is high in fats and low in carbohydrates. Remarkably, a simple dietary change has shown to significantly reduce the severity and frequency of seizures in dogs.

Also, diet is also essential for dogs who are presently being treated with conventional anti-seizure medications. We discussed that these drugs are directly tied to kidney damage. Therefore, an exceptionally balanced diet will be paramount in ensuring that the body has enough support to help rebuild and protect the organ from additional damage occurring.


Finally, experts have found that the use of Chinese medicine such as acupuncture can have positive effects for dogs (and people) suffering from epilepsy. Keeping that in mind, acupuncture works best with strict consistency and may not be an appropriate match for everyone's lifestyle. Either way, the fact that so many pet owners are seeing benefits from alternative healing is something that we can all be grateful for.

Knowledge is Power 

The last thing that we want to mention is the importance of staying aware of new breakthroughs in pet wellness. For instance, new studies have found that several flea and tick medications are directly liked to an increase in seizure activity in epileptic dogs. Knowing all there is to know about your dog's condition and how to prevent it from worsening can truly affect your dog's wellbeing and make a difference in their quality of life.

Phenobarbital for Dogs: The Bottom Line

When all is said and done, we know that you want the very best for your beloved four-legged family member. As an owner of an epileptic dog, we understand that all you want is for your pup to be seizure free and live a long, happy life. We're here to tell you that we believe that day is coming. With the constant advancements in both conventional and holistic medicine, we truly feel that epileptic dogs will soon be able to live lives free of seizures and the associated effects of many anti-seizure medications. In the meantime, as a pet owner, you must ensure that you are doing everything you can to understand your dog's condition and make educated decisions for their wellbeing. In many cases, this may mean forgoing the use of a drug such as Phenobarbital.


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