What Is Phenobarbital?
Phenobarbital is a barbiturate. A type of depressant, barbiturates affect the central nervous system. Phenobarbital is also known as Barbital or Luminal. It is used to control the severity and extent of seizures. It does this by lowering and balancing the activity of neurons in the dog’s brain.
Dog’s seizures can be caused by some underlying health problems such as toxin ingestion, brain tumor, head injury, kidney disease, anemia and liver shunt. If there is no underlying cause, the seizure is considered to be epilepsy.
The drug also decreases the Glutamate neurotransmitter. Glutamate is the one responsible for sending signals between nerve cells.
If the dog is experiencing seizures, remain calm. Try to calm the dog as well. This will prevent further problems such as brain trauma or brain cancer. Putting light pressure on the dog’s eyeball can decrease the duration of the seizure.
You should also record the severity and duration of the seizure. This will help the veterinarian evaluate the dog’s case better. The information recorded can also help the veterinarian calculate how much phenobarbital will be given to the dog.
Dogs prone to seizures are:
- Basset Hound
- Belgian Tervuren
- Golden Retriever
- Shetland Sheepdog
- Cocker Spaniel
- Labrador retriever
The medication should not be given to dogs with the following conditions:
- Respiratory Problems
- Kidney Disease
- Addison’s Disease
- Liver Disease
- Heart Disease
Phenobarbital is a strong barbiturate that can alter the function of the dog’s organs. It can also affect the dog’s blood. It is wise to consult a veterinarian before giving any medications to your pet.
The dosage depends on the dog’s breed and weight. It also depends on the severity and frequency of the dog’s seizures.
Typically, the veterinarian will start a dose of 1-2 mg per pound of the dog’s body weight. Depending on the severity of the seizure, the dose can increase up to 8 mg per pound per day. The dose also depends on the dog’s response to the medication.
The medication is often given in doses measured in “grains” rather than milligrams. One grain is equivalent to about 60 milligrams. It is available in ¼ grain, ½ grain, 1 grain and 100 milligram tablets.
Injectable form of the medicine is also available. This comes in 65 and 130 milligram or milliliter doses.
The medication should be given every 12 hours. In case a dose was missed, never give two doses of the medication at once. This can result to nervous system depression, and even phenobarbital poisoning.
If you want to stop giving the medicine to your dog, do it gradually, and do it with the guidance of your veterinarian.
Phenobarbital Side Effects
If the dog is using the medicine for the first time, it will be groggy and wobbly. This will eventually disappear as the dog gets used to phenobarbital.
Other side effects of the medicine include:
- Loss of Coordination
- Increased Urination
- Increased Thirst or Appetite
- Weight Gain
- Hyper excitability
- Liver Damage – The side effect may be caused by long-term use of the medicine.
Signs of liver damage or liver failure include the following:
- Diarrhea and changes in stool
- Jaundice (yellow coloring of mucous membrane and skin)
- Anorexia or loss of appetite
Phenobarbital is commonly used to treat seizures in dogs because it is inexpensive. 15-16. 2 mg tablets cost around 1.32 dollars per tablet. 30- 32.4 milligram tablets cost around 1.48 dollars per tablet.
Phenobarbital Interaction with Other Drugs
Drugs that can strengthen the effect of phenobarbital include chlorambucil, griseofulvin and some antihistamines. It is not wise to combine these medicines as it will increase the effect of phenobarbital. This can damage the dog’s brain cells, and can also lead to overdose.
There are also drugs that interfere with phenobarbital. These drugs include beta-blockers, some steroids and metronidazole. Other medicines that do not work well with phenobarbital include Lysodren (used to treat Cushing syndrome), Theophylline (airway dilator) and cyclosporine (for immune mediated diseases). These medicines make phenobarbital less effective. They can even worsen the frequency of seizures.
Some medicines help taper side effects of phenobarbital. These medicines help balance the effect so as not to damage other organs of the dog. These medicines include Potassium Bromide.
The active ingredient is phenobarbital.
In 15 mg, 30 mg and 60 mg phenobarbital, the other ingredients are:
- Calcium Stearate
- Colloidal Silicon Dioxide
- Corn Starch
- Microcrystalline Cellulose
In 100 mg of phenobarbital, other ingredients are:
- Anhydrous Lactose
- Docusate Sodium
- Colloidal Silicone Dioxide
- Magnesium Stearate
- Lactose Monohydrate
- Sodium Starch Glycolate
- Microcrystalline Cellulose
Phenobarbital is an effective medicine to help treat seizures, but it has strong side effects. There are other medicines that have lesser side effects than phenobarbital.
Diazepam, commonly known as Valium, is an anti-convulsant drug. It helps reduce the neuron’s activity.
Levetiracetam, also known as Keppra, is an anticonvulsant drug. It has a lower dosage of phenobarbital. This means it has lesser adverse effects.
Zonisamide or Zonegran is a new anti-seizure drug for dogs. The starting dose is higher than phenobarbital, but it has lesser side effects.
Changes in the dog’s diet can help reduce seizures. A ketogenic diet is advised by veterinarians. The diet is high in fats and low in carbohydrates.
Acupuncture is also a way to reduce the frequency and severity of seizures. This works best with strict consistency.
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