Treating Cat Seizures With Phenobarbital

Phenobarbital is the number one choice of anti-convulsants for recurrent and uncontrolled feline seizures (such as in epilepsy). It functions as a muscle relaxant and a depressant, thus effectively quelling seizures and helping to stabilize the cat.

Cat Epilepsy vs. Cat Seizures

Seizures are a symptom, and usually caused by a disease other than epilepsy. A cat that has a seizure may not necessarily have epilepsy. Feline seizures can range from unusual mood swings to violent physical convulsions, and often will have an underlying cause. Cancer, metabolic diseases, inflammatory disease or trauma may cause them. Many times, recurrent seizures and fits will vanish after another disorder has been treated.

Epilepsy is the disease described as recurrent and uncontrolled seizures that have no apparent cause. There are two types of epilepsy: idiopathic (primary) epilepsy, and symptomatic (secondary) epilepsy. The first applies to "classic" epilepsy - seizures with no known cause. Trying to prove primary epilepsy is difficult, as cats are more susceptible to seizures when infected with a disease than other animals. More often than not, the epilepsy is the second, more common type of epilepsy that happens when the recurrent seizures become identified as the manifestation of an underlying problem.

As seizures (epileptic or not) are usually caused by a nervous system malfunction, a series of tests are required to properly diagnose the condition. Once diagnosed, phenobarbital may be prescribed to ease the convulsions, while additional medication may be needed to treat the actual disorder causing the seizures.

Phenobarbital for Cats

Phenobarbital is the most widely used barbiturate (nervous system depressant) worldwide. It comes in three forms: tablet, liquid and injection. For cats, injection is the most common method of administration, followed by liquid medication. Phenobarbital has an extraordinarily long half-life, so for many cats, a daily dosage is not required. This is particularly true after several weeks of medication, and the phenobarbital has built up in the cat's system.

Phenobarbital Side Effects

Phenobarbital is generally considered safe for use in cats. However, a few adverse reactions have occurred, including:

  • Lethargy
  • Agitation or irritation
  • Dehydration
  • Excessive urination
  • Loss of coordination

A few cats also have allergic reactions, though the reaction is not quite the same as a regular tablet or pill medication. Allergic reactions include:

  • Low platelet count
  • Low white blood cell count
  • Facial swelling
  • Skin irritation

For cats with allergies, Diazepam is often prescribed. In addition to allergic reactions, phenobarbital has been known to aid in the creation of blood clots, and cause liver damage, though this is very rare in cats.

Reactions with Other Medications

Phenobarbital may interact with the following:

  • Antihistamines
  • Phenothiazines
  • Corticosteroids
  • Some beta blockers
  • Chloramphenicol
  • Doxycycline
  • Quinidine
  • Metronidazole
  • Theophylline
  • Griseofulvin
  • Phenytoin
  • Phenoxybenzamine

Interactions between phenobarbital and other medications may cause protein changes, leading to harmful effects for your cat. It is important to tell your veterinarian if your cat is on any of these medications.

Phenobarbital is the oldest and most popular anti-convulsant and depressant drug that is used to fight recurrent seizures in cats.