Phenobarbital

Updated on September 10, 2024

Barbiturate used as an anti-seizure medication.

Phenobarbital

Summary

Used For: Used to control seizures and sedative and for controlling excessive feline vocalization.

Brands: Solfoton®, Luminal® or Barbita®

Species: Dogs, cats, ferrets

Drug type: Anti-seizure

Prescription required: Yes

Pregnancy and lactation: Use cautiously in pregnant or lactating animals.

Side effects: Sedation, lethargy, ataxia, anxiety, increased appetite, increased water intake, increased urination

Uses

Phenobarbital is primarily used in veterinary medicine to control epilepsy and seizures. Also used as a sedative and for controlling excessive feline vocalization.

How it works

Phenobarbital works by decreasing the abnormal electrical activity in the brain that happens during a seizure.

Dosage

* Dogs: For initial therapy, 2.5 - 3 milligrams per kilogram of body weight orally every 12 hours. Dose adjusted based on drug levels, therapeutic results, and adverse reactions. * Cats: For initial therapy, 1 –3 milligrams per kilogram of body weight, or 7.5 to 15 milligrams per cat every 12 hours orally. Dose adjusted based on drug levels, therapeutic results, and adverse reactions. * Ferrets: 1-2 milligrams per kilogram of body weight orally every 8-12 hours.

Forms

Phenobarbital tablets for oral use in 15, 16.2, 30, 60, 90, and 100 milligram sizes. Phenobarbital oral solution is formulated at 20 milligrams per 5 milliliters (4 milligrams/milliliter).

Storage information & handling

Store in a tight, light resistant, childproof container at room temperature.

What results can I expect?

Reduction in the severity and frequency of seizures. Most veterinary neurologists agree that “good seizure control” exists when the patient has one seizure per month or less.

Missed Dosage

It is best to give the medication at the same time every day without skipping doses. If you miss a dose, give it as soon as possible. If it is almost time for the next dose, skip the one you missed and go back to the normal schedule. Do not give 2 doses at the same time.

Overdose / acute toxicity

May see staggering, sedation, loss of appetite, vomiting, depression, jaundice (yellow gums, skin, eyes), decreased breathing and heart rate, coma, and death. If you think your pet has had an overdose seek veterinary care immediately.

Side effects

* Sedation * Lethargy * Agitation/anxiety * Ataxia/staggering * Increased appetite * Increased drinking * Increased urination * Liver damage with jaundice and/or anemia

Contraindications

* Previous sensitivity * Liver disease * Anemia * Cardiac or Respiratory disease * Dehydration * Addison’s Disease

Drug interactions

Consult your veterinarian before using any other medications with phenobarbital, even vitamins and supplements. Interactions may occur with acetaminophen, NSAIDs (e.g., aspirin, carprofen, firocoxib, etodolac, deracoxib, and meloxicam), MAO inhibitors (amitraz, selegiline), phenytoin, and rifampin. Antihistamines, chloramphenicol, felbamate, opiates, phenothyazines, urinary acidifiers, and valproic acid may increase the effects of phenobarbital. Phenobarbital may decrease the effect of oral anticoagulants (blood thinners, warfarin), beta blockers (propranolol), chloramphenicol, corticosteroids (e.g., prednisone, dexamethasone), doxycycline, griseofulvin,itraconasole, levothyroxine, metronidazole, praziquantel, theophylline, tricycline antidepressants, urinary alkalinzers, zonisamide.

Sources

Plumb's Veterinary Handbook
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Disclaimer

The information contained on this page is for educational purposes only. This medication should only be given under the advice of a veterinarian who has examined your pet under the laws applicable to your state of residence.