Phenobarbital Drug Information for Dogs and Cats

By: Dr. Alex Avery, BVSc | Reviewed by: Dr. Ryan Llera, B.Sc., DVM | Published by: Healthcare for Pets | May 17, 2019

Phenobarbital Drug Information Sheet for Dogs and Cats

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Quick Info:


  • Drug name: Phenobarbital
  • Common name: Epiphen, Phenobarb, Solfoton, Luminal, generics
  • Drug type: Barbiturate
  • Used for: Seizure control
  • Species: Dog + cat
  • Formulation: Injectable, tablets, oral solution


Name – Active Ingredient:


  • Phenobarbital


Name – Common Trade Names:


  • Epiphen, Phenobarb, Solfoton, Luminal, generics






Major Indication:


  • Anti-epileptic, anti-seizure drug
  • Sedative


Common Contraindications and Warnings:


  • Use with caution in patients that are dehydrated, anaemic, pregnant or lactating, or have heart or lung disease.
  • Do not use when liver function is impaired.


Potential Side Effects:


  • Sedation and wobbliness are frequently seen when treatment is started. These typically resolve within a week unless high doses are given.
  • Raised liver enzymes are common but do not generally indicate liver dysfunction.
  • Rare side effects include excitability, liver damage/failure, blood cell disorders, and skin disease.


Administration Instructions/Handling:


  • Give with or without food. If vomiting is seen when given without food, try giving with food instead.
  • Give entire course as instructed by your veterinarian (even if the pet seems 100% recovered).
  • Do not skip doses or suddenly stop treatment, as this may result in seizures. If a dose is missed, give at the earliest opportunity and then again when next due.




  • It takes 12 to 14 days in dogs and 9 to 10 days in cats for blood levels to stabilize and the full ability of the drug dose to be evaluated.
  • Regular blood testing should be carried out to:
    • Monitor the level of phenobarbital in the blood as this level tends to decrease with time, meaning a higher dose may be required
    • Ensure liver damage is not occurring
  • Monitor seizure frequency and severity – keep a seizure diary.


Speed of Action + Monitoring:


  • Antibiotics start working straight away, but it can take several days for an effect to be seen depending on the type of infection and how long it has been present.
  • If your pet is not recovering, then culture and sensitivity testing may be needed (if it has not already been carried out) or the diagnosis re-evaluated.




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Phenobarbital Drug Information for Dogs and Cats
Article Name
Phenobarbital Drug Information for Dogs and Cats
This resource provides drug information for dogs and cats taking phenobarbital.
Publisher Name
Healthcare for Pets
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