The Side Effets of Phenobarbital for Dogs

In epileptic dogs, Phenobarbital is the most commonly prescribed medication. Epilepsy is most common in certain breeds of dog, like German Shepherds, Irish Setters and Golden Retrievers, for which Phenobarbital, a barbiturate, is very effective.

Main Function of Phenobarbital

Phenobarbital is an inexpensive and easy to use drug, which makes it the most popular canine seizure medication on the market. Phenobarbital isn't FDA approved for dog usage, but veterinarians tend to prescribe it due to its efficiency.

Treating between 60 and 80% of cases of idiopathic dog epilepsy effectively, dog owners can administer the drug on a daily basis to stop seizures, or administer it mid-seizure to stop the shaking.

How Phenobarbital Works

Seizures occur when the neurons in your dog's brain overexcite and emit signals faster than they normally do. Phenobarbital reduces the activity of neurons in your dog, which prevents seizures. Because Phenobarbital can't pinpoint which neurons in particular to inhibit, this affects other neurons.

The drug augments the activity of a chemical called gamma-aminobutyric acid in the brain that stops signals from passing from one neuron to the next. Taking the drug daily stops dog seizures by reducing electrical energy.

Side Effects of Phenobarbital

As a result, many of the side effects of Phenobarbital are neurological. You'll notice your dog appearing lazy, sedated, restless, hyper-excited or uncoordinated (ataxia). These side effects will disappear after a few weeks of treatment when your dog's system gets used to the medication.

Long-term side effects of Phenobarbital include frequent urination, excessive drinking and eating. Because your dog is eating more, he'll most likely gain weight, a secondary effect of the drug. Although, it's rare, Phenobarbital can also cause anemia, which would necessitate discontinuation of treatment.

Liver Damage Most Dangerous Side Effect of Phenobarbital

Liver damage is the most dangerous side effect of Phenobarbital. Although it only occurs in a small percentage of dogs, long-term use of Phenobarbital can cause scarring of the liver, and subsequent liver failure.

A reduction in the amount of Phenobarbital taken can prevent any long-term damage to the liver. Additionally, by monitoring blood levels frequently will help alert you to any problems in your dog's body before it is too late. Symptoms of liver damage to watch out for include jaundice, weight loss, vomiting and dark urine.

Liver damage can be presented by combining Phenobarbital with potassium bromide or milk thistle. Potassium bromide allows vets to prescribe a lower dosage of Phenobarbital in order to lower the likelihood of developing liver damage, but can affect the salt levels of your dog's diet. Monitor his salt intake after beginning treatment.

Phenobarbital Alternatives

There have been a number of new medications in their beginning stages for treating epilepsy in dogs without the risk of liver damage, but the majority is very expensive. Phenobarbital remains the most effective and reasonably priced medication on the market.