Customer Service: [email protected] +1 (844) 673-7287 • 9am - 5pm EST (M-F)

Phenobarbital for Dogs: Uses, Safety & Side Effects

Ellevet Dog with laptop

One of the most fear-inducing events in your pet’s life can be suffering a seizure, whether it be an isolated incident or an ongoing one. It is equally terrifying as a pet owner, as you feel helpless against this seemingly uncontrollable condition that is taking over your beloved friend. 

Thankfully, veterinarians have an answer in the form of Phenobarbital. This barbiturate medication is prescribed to dogs (and cats) as a seizure medication. 

What is Phenobarbital? 

As we mentioned, Phenobarbital is a barbiturate medication. Barbiturate medications usually carry with them a calming, sedative effect. Phenobarbital comes in a variety of different names and brands, including Luminal Sodium, Solfoton, and Tedral. 

In small animals like cats and dogs, it is used mainly to treat seizure conditions. And as is the case with a majority of medications, when used in the animal health industry, veterinarians will prescribe this medication as “off-label”. Off-label or “extra-label” medications are used differently on a case-by-case basis, meaning the dosing amounts and frequency may be much different from what is listed on the actual product. This makes it imperative to follow your veterinarian’s directions accurately. 

Common Causes of Seizures in Dogs: 

  • Head Injury
  • Brain Cancer 
  • Kidney Disease
  • Liver Disease 
  • Poison 
  • Epilepsy 

How is it given to dogs? 

Phenobarbital comes in several forms. It is available as a tablet, liquid, paste, and chewable. If you’d like to have your veterinarian administer your dog’s dose and no other form seems to work, Phenobarbital is also available as an injection. It is metabolized differently by different breeds, so exact dosing amounts can also vary based on weight, breed, and severity of seizures.

Other than the injections, it is given orally, every 12 hours, with or without food. If you accidentally miss a dose, do not give your dog 2 doses at once to make up the difference! Simply move on from the missed dose and continue your dosing schedule as normal. Phenobarbital is not observed to be an instantaneous drug, meaning it will take a few doses to start seeing results. It may actually take a few weeks to see the full effects of Phenobarbital. Your veterinarian will likely want to monitor your dog’s bloodwork during their Phenobarbital use (typically every 3-6 months for as long as administration continues). 

Side Effects

Barbiturate medications like Phenobarbital can include moderate side effects. Some are more common than others. 

Common Side Effects of Phenobarbital: 

  • Anxiety 
  • Lethargy
  • Sedation
  • Agitation 
  • Increased Appetite and Thirst 

Most of these side effects are moderate and common in nature, but they are still something to be aware of. Less common side effects include decreased blood cell counts and liver dysfunction. Additionally, if your dog is showing signs of incoordination or extreme sedation, this could be a sign that the dose is too high. If you observe any of the side effects listed or discussed here, contact your veterinarian right away for the next steps. 

Safety & Drug Interactions

Phenobarbital is known as a generally safe and effective medication, but the possibility of negative interactions is present. 

Acetaminophen, benzodiazepines, carprofen, monoamine oxidase inhibitors, opioids, phenytoin, and rifampin should all be used with caution when taken in conjunction with Phenobarbital. 

Furthermore, some drugs may actually increase the effects of Phenobarbital, including opioids, antihistamines and bromides. For a full list of possible interactions, we recommend consulting your veterinarian, as they will be able to go in-depth about any and all medications or supplements your dog is currently taking, and how those may affect Phenobarbital use. 

Finally, don’t stop Phenobarbital use abruptly. Follow your veterinarian’s dosing instructions accurately and all the way through, as stopping barbiturate use suddenly cause health issues and even worsen existing seizure conditions.

The ElleVet Team
[email protected]