Phenomav (Phenobarbital)

Phenomav is a medication for treating seizures in dogs. Its active ingredient is Phenobarbitone (a.k.a. phenobarbital), a commonly used barbiturate in veterinary medicine for managing seizure disorders in pets. Phenomav is licensed for use in dogs and its use in other species is considered off-label.

Phenobarbitone controls seizures in dogs by potentiating the activity of GABA, an inhibitory neurotransmitter. This action helps stabilise neuronal activity in the brain and prevent excessive firing that can lead to seizures. Phenobarbital also suppresses rapid and repetitive neuron firing, reducing the frequency and severity of seizures.

Give Phenobarbitone as directed by your veterinarian. Dosage and frequency will depend on several factors, such as your pet's size and condition. It is usually given every 12 hours. It is crucial to maintain consistency in dosing and avoid abruptly stopping the medication. Missing even one dose may trigger seizures in some pets, so it's essential to adhere fully to medication recommendations. It can be administered with or without food.

Missed Dose:

If you miss a dose, give the dose as soon as you remember it, then give the next dose at the appropriate time interval, and then return to the regular dosing schedule. If a breakthrough seizure occurs, an additional dose may be given under the guidance of your vet.

If you have missed a dose and it is basically time for the next dose, skip the missed dose and continue with the regular schedule. Never double-dose.

Overdose:

In case of an overdose or adverse reaction, immediately contact your veterinarian or New Zealand National Poisons Centre (www.poisons.co.nz/animal-helpline/ or phone 0800 869 738).

Liver Disease: Animals with pre-existing liver disease or impaired liver function should avoid phenobarbital.

Respiratory problems: Phenobarbital can depress the central nervous system, leading to decreased respiratory rate. It should be used with caution or avoided in animals with respiratory problems.

Pregnancy: It should be used cautiously in pregnant animals due to the risk of causing birth defects or neonatal depression.

Severe Anaemia: Phenobarbital may cause further depression of the central nervous system in patients with severe anaemia.

Hypersensitivity: Animals with a known hypersensitivity to phenobarbitone or barbiturates should not be given the drug.

Kidney Disease: Although primarily metabolised by the liver, impaired kidney function can affect the elimination of the drug and its metabolites, requiring careful consideration or adjustment of dosage.

Sedation during initial treatment: If the symptoms last for more than two weeks, a blood test can determine if the dose needs to be adjusted.

• Ongoing Sedation: Treatment aims to stop seizures, not sedate the patient. Phenobarbitone usually doesn't cause sedation, but if it does, the dose may be too high. Patients who can't tolerate phenobarbital may need a different medication or a lower dose with a second medication.
• Excessive Appetite
• Excessive Thirst
• Long-term treatment may cause scarring in the liver and liver disease. Routine blood tests can detect early liver changes and preventive action can be taken.
• Cats can get itchy faces on phenobarbitone
• Anaemia (lack of red blood cells)

If your pet experiences any side effects, discuss them with your vet. Your pet's medication regimen may need adjusting.

Store the medication at room temperature, protected from light and moisture. Keep out of reach of children and other pets.

What is Phenobarbitone used for in dogs and cats?

• Phenobarbitone is primarily used to treat seizures and epilepsy in dogs and cats by reducing the frequency and severity of episodes.

How long does it take for Phenobarbitone to work in pets?

• Phenobarbitone typically starts to work within a few hours of administration, but it may take several weeks to achieve optimal seizure control.

 Are there any side effects of Phenobarbitone in dogs and cats?

• Common side effects include increased thirst and urination, increased appetite, lethargy, and coordination issues. Long-term use may affect liver function.

How often do pets need to take Phenobarbitone?

• Phenobarbitone is usually given twice daily, but the exact dosage and frequency depend on the pet's condition and response to the medication.

Do pets need regular monitoring while on Phenobarbitone?

• Yes, regular blood tests are necessary to monitor liver health and blood levels of phenobarbital to ensure efficacy and minimise risks of toxicity.