Managing Epilepsy in Dogs with Primidone

Primidone is a drug used for the long term management of epilepsy in dogs. It's an anticonvulsant and is related to Phenobarbital. It's metabolized to Phenobarbital and Phenylethylmalonamide, both of which are also anticonvulsants. Since Primidone is a prescription drug, it should be used according to vet instructions. It reduces the severity and frequency of seizures as it decreases the nerve impulses in the pet's nervous system.

General Dosage Guidelines

Primidone is available in 50 mg and 250 mg tablets and 50 mg/ml suspension. As a general guideline, the usual dose for canines is 5 to 15 mg per pound of body weight per day. This is divided into 2 or 3 doses to suit individual dog needs. If seizures aren't controlled, the dosage might have to be increased. To prevent a relapse, care should be taken to complete the treatment and avoid sudden discontinuation of the drug. This is advisable even if the dog shows signs of complete recovery. Increasing the dosage might cause severe side effects and decreasing the dosage might increase the chances of the dog suffering a seizure. If a decrease in dosage is recommended, the decrease should be gradual. However, in most cases, the medication has to be administered for life.


  • Primidone shouldn't be administered to dogs that are allergic to the drug or to anemic pets.
  • It's contraindicated in pregnant or lactating dogs. This drug is also not to be administered to dogs intended for breeding purposes.
  • Primidone is contraindicated in dogs with diseases of the heart, the lung, the kidneys and the liver.
  • The vet should be advised if the dog is on any other medication such as tranquillizers, sedatives, antihistamines, vitamins, supplements and barbiturates to avoid possible drug interactions.

Side Effects Include:

  • Restlessness
  • Lethargy
  • Increased water intake
  • Drowsiness
  • Dizziness
  • Anxiety
  • Increased appetite
  • Liver problems that could be severe enough to be fatal


An overdose of this drug can cause an emergency situation and it's imperative to contact emergency animal care at the earliest. Some of the symptoms of overdose are increased heart rate, increased thirst, skin disease, increased appetite, vomiting, kidney disease and panting. This could escalate and the dog might go into a coma. In severe cases of overdose, death could also occur.


Blood tests should be carried out 14 days after the treatment is first administered to measure the Primidone levels in the blood. Once the dog has stabilized, the levels in the blood serum should be monitored every 6 months to ensure that they remain within the normal range. Liver enzymes and bile acid tests should also be carried out on a regular basis, as Primidone can have adverse effects on the liver.

Brand Names

Primidone is an ingredient present in commercial drugs such as Neurosyn, Mylepsin, Primidone tablets and Primidone Medi-Pets.

Pet owners should learn techniques to manage dogs suffering from epilepsy. It's important to stay calm during a seizure and keep animal emergency numbers at hand. Pet owners should also make note of the symptoms exhibited during the seizure and the duration it lasts.