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Overview of Phenobarbital for Dogs and Cats
- Phenobarbital, also known as Luminal® or Barbita®, is most commonly used to treat seizure disorders including epilepsy in dogs and cats. Phenobarbital is considered the first line of treatment for control if epileptic seizures in dogs and cats.
- Seizure disorders or convulsions are the physical manifestations of uncontrolled electrical activity in the brain. Recurrent seizures are often classified as epilepsy (fits). While there are numerous causes of convulsions, treatments that control epileptic seizures are relatively limited. Commonly used anticonvulsant drugs include phenobarbital, diazepam (Valium®) and primidone.
- Phenobarbital is a barbiturate drug with anticonvulsant properties. It can help reduce the frequency and severity of seizures; at low to moderate doses this occurs without excessive sedation.
- Phenobarbital is a controlled substance schedule IV, and is available only through a DEA-licensed veterinarian.
- Phenobarbital is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.
- This drug is not approved for use in animals by the Food and Drug Administration but it is prescribed legally by veterinarians as an extra-label drug.
Brand Names and Other Names of Phenobarbital
- This drug is registered for use in humans only.
- Human formulations: Luminal® (Winthrop-Breon), Barbita® (Vortech) and various generic preparations
- Veterinary formulations: None
Uses of Phenobarbital for Dogs and Cats
- Phenobarbital is most commonly used to treat seizure disorders including epilepsy in dogs and cats.
- It has also been used as a sedative.
Precautions and Side Effects
- While generally safe and effective when prescribed by a veterinarian, phenobarbital can cause side effects in some animals.
- Phenobarbital should not be used in animals with known hypersensitivity or allergy to the drug.
- Phenobarbital should be used with caution in animals with anemia, heart, liver or lung disease.
- Phenobarbital may interact with other medications. Consult with your veterinarian to determine if other drugs your pet is receiving could interact with phenobarbital. Such drugs include antihistamines, narcotics and tranquilizers.
- At high dose levels, phenobarbital is a sedative and can result in nervous system depression.
- Adverse effects associated with phenobarbital include restlessness, anxiety, lethargy, depression, increased appetite and increased thirst. These side effects are generally brief and may not be evident after prolonged treatment.
- After prolonged use, phenobarbital can result in significant liver impairment.
How Phenobarbital Is Supplied
- Phenobarbital doses are frequently referenced as “grains” (an old method of measuring) as opposed to milligrams. One grain is equal to approximately 60 mg.
- Phenobarbital is available in 1/4 grain, 1/2 grain, 1 grain and 100 mg tablets.
- Phenobarbital elixirs of various concentrations are also available.
- Phenobarbital for injection, 65 mg/ml and 130 mg/ml, also is available.
Dosing Information of Phenobarbital for Dogs and Cats
- Medication should never be administered without first consulting your veterinarian.
- Most often, phenobarbital therapy in dogs is begun at 1 to 2 mg per pound (2 to 4 mg/kg) twice daily. In cats, phenobarbital is dosed at 7.5 to 15 mg per cat every 12 hours.
- Based on response, the dose may be increased up to 8 mg per pound (16 mg/kg) per day.
- The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse or prevent the development of resistance.