ACVIM Releases Consensus Statement on Seizure Management in Dogs

The American College of Veterinary Internal Medicine (ACVIM) has released a consensus statement on the management of seizures in dogs.

The consensus panel notes that diagnosing epilepsy in dogs is not straightforward, that treatment strategies vary, and that few evidence-based studies of new antiepileptic drugs have been published. “As a result, many primary care clinicians are left to treat epilepsy with lack of uniform, scientifically based guidelines,” write the authors. “The purpose of this paper was to build on previous work by providing a scientific and working clinical consensus statement on seizure management in dogs based on current literature coupled with clinical expertise.”

When to Begin Treatment

The panel recommends starting antiepileptic treatment in patients with 1 of the following:

• A structural lesion or a history of brain disease/injury

• Acute repetitive seizures: ictal event lasting 5 minutes or longer or 3 or more seizures within 24 hours
• Two or more seizures within 6 months
• “Prolonged, severe, or unusual” postictal periods

Which Drug to Use First

The consensus statement focuses on 6 antiepileptic drugs: phenobarbital, potassium bromide, primidone, imepitoin, levetiracetam, and zonisamide. The recommendations for selecting a first-line drug are based on tolerability as well as effectiveness:

• Phenobarbital and imepitoin: high recommendation
• Bromide: moderate recommendation
• Levetiracetam and zonisamide: low recommendation
• Primidone: not recommended

Although primidone is the only antiepileptic drug approved for dogs in the United States, studies cited by the authors show that phenobarbital (a metabolite of primidone) provides better seizure control and is better tolerated.

Monitoring

The statement includes details of drug doses, trough serum level monitoring times, and serum level reference ranges. The panel notes that therapeutic ranges should ideally be determined on an individual basis. Monitoring is not recommended for imepitoin and levetiracetam, although the authors indicate that monitoring levetiracetam levels may be useful when it is used together with phenobarbital.

Risks of Treatment

The consensus panel assigned up to 4 adverse-effect categories to each drug. Imepitoin and levetiracetam were placed in only the lowest category (predictable adverse effects that are related to pharmacologic effects). No drugs fell into the highest category (life-threatening effects that are carcinogenic or teratogenic).

Adding a Second Drug

The panel does not list specific criteria for adding a second antiepileptic drug. Factors to consider include the following:

• Seizure frequency
• Seizure severity
• Quality of life
• Selection of drug with a different mechanism of action
• Drug-drug interactions
• Toxicity

The panel’s recommendations for add-on therapy are as follows:

• Phenobarbital, bromide, levetiracetam, and zonisamide: moderate recommendation
• Imepitoin: low recommendation
• Primidone: not recommended

Alternative Treatments

The authors report equivocal results for vagal nerve stimulation, diet alteration, and acupuncture, with possible benefits reported although the quality of evidence is not high. There is no evidence currently supporting homeopathy for epilepsy treatment.

Quality of Life

“The most important outcome measure of a chronic medical condition such as epilepsy is quality of life,” write the authors. With dogs, the outcome depends not only on the degree of seizure control but also on the emotional and financial burden borne by the owners. Seizures tend to be more severe in certain breeds (eg, Border collies and Australian shepherds), and the prognosis is poorer in dogs with structural epilepsy than those with idiopathic epilepsy. The panel recommends helping owners assess quality of life in regards to both the dog and themselves.

Dr. Laurie Anne Walden received her doctorate in veterinary medicine from North Carolina State University in 1994. After an internship at Auburn University College of Veterinary Medicine, she returned to North Carolina, where she has been in companion animal general practice for over 20 years. Dr. Walden is also a board-certified Editor in the Life Sciences and owner of Walden Medical Writing.