CONTRIBUTOR(S): Vetstream Ltd, Gigi Davidson,
Medication: Primidone
Medication: Primidone
Your dog has been prescribed primidone for the management of seizures.
Key points:
• Anti-seizure/anti-epileptic.
• Prodrug to phenobarbital (converted to phenobarbital in the body).
• Toxic to cats.
• Dosage: two to three times daily.
This information sheet is designed to help answer commonly asked questions and help you give the medication safely and effectively to your pet. It does not contain all available information for this medication. If you have other questions or need more information, contact your veterinarian or pharmacist. Always follow the dosing instructions provided by your veterinarian.
Name, Brand names, Class of medication and Storage
Name
- Primidone (Pri-mid-own).
Brand name
- Primidone Tablets: 50 and 250 mg; Mylepsin®, Neurosyn® (US).
- Primidone (Generic) 50mmg Tablet (US).
- PrimiTabs (US).
Class of medication
- Anti-seizure.
Storage
- Store at room temperature (20-25°C/68-77°F) protected from heat, light, and moisture.
Why has my dog been prescribed primidone?
Your veterinarian has prescribed primidone for the treatment of seizures. Primidone is converted to phenobarbital in the body as well as another active metabolite, PEMA. For dogs that do not respond to phenobarbital alone, many veterinarians will prescribe primidone.
How is the medication given?
Primidone is given orally (as tablets). It is administered two or three times daily. Tablets can either be administered directly into your dog’s mouth or along with some food. It may take a while to ascertain the correct dose for your pet. It is important to follow dosing guidelines carefully. Never stop this medication suddenly.
Are there any side-effects or drug interactions?
Your dog may become excited or restless at the beginning of treatment. Most dogs adjust to this over time.
Very rarely, hypersensitivity reactions (allergic reactions) may occur. If this happens, stop the treatment and contact your veterinarian immediately.
Reported side-effects include: sedation, loss of balance, drinking, eating and urinating more than usual, abnormal eye movements, increased heart rate, heavy breathing, loss of appetite, personality changes and skin problems. Liver enzymes will increase in the majority of dogs receiving primidone. Long term use has been associated with liver disease. Contact your veterinarian if you feel your pet has any side-effects from this medication.
The following drugs may interact with primidone:
- Griseofulvin, acetazolamide, chloramphenicol, antihistamines, valproic acid, beta-blockers, corticosteroids, metronidazole, anticoagulants, quinidine, theophylline and barbiturates. Tell your veterinarian about any medications or supplements your dog is receiving at home.
Primidone can also cause changes in the liver that increase its elimination and dosages may need to be increased over time.
Primidone can alter the results of thyroid tests. Thyroid testing should be performed no sooner than 4 weeks after the discontinuation of primidone.
How long will my dog need to receive this medication?
Primidone tablets should be administered according to your veterinarian’s instructions. Your pet may need this medication for life.
How should I dispose of this medication if I don’t use it all?
Dispose of any unused primidone safely – do not flush down the toilet or sink. Ask your veterinary team if they take back medication for disposal. Do not give to other pets.
What if I miss a dose or give an extra dose?
If you miss a dose, give the dose as soon as possible but do not give a double dose. Make sure the dose given does not exceed the total recommended dose in any 24-hour period.
My dog is unwell, should I still give the drug?
If your pet is unwell, contact your veterinarian for advice.
What should I do if this medication is accidentally given to another pet or taken by a human?
Primidone should only be given to the dog that it has been prescribed for. If accidentally given to other pets, contact your veterinarian for advice.
Primidone is toxic to cats.
If accidentally consumed by a human, speak to your primary care physician or poison control center.
Will my dog need to be monitored while on primidone?
Your dog may need regular blood tests to check liver function and to ensure that the dose of primidone is correct. Your veterinarian will monitor the levels of phenobarbital (the active metabolite of primidone) approximately every 6 months to make sure that the dosage is still correct.
Further information
If you have any concerns, further information on primidone can be found on the package insert and the following websites:
Europe & UK
- There are no licensed veterinary products available in the UK containing primidone. Your veterinarian will explain the regulations regarding prescribing unlicensed products.
US
- VetRxDirect Primidone (Generic) 50 mg Tablet. Website: www.vetrxdirect.com/product/view/primidone-anticonvulsant-tablets-for-dogs-rx
- Henry Schein Animal Health PrimiTabs. Website: www.drugs.com/vet/primitabs.html
- Mylepsin® 250 mg Tablet Animal Drugs. Website: animaldrugsatfda.fda.gov/adafda/views/#/home/previewsearch/010-091
Always follow the recommended dosage and contact your veterinary team or pharmacist if you have any questions regarding your dog’s medication.