FASAVA Congress 2017

Appropriate therapy for a seizure disorder depends on accurate determination of the cause of the seizures. Treatment with antiepileptic drugs (or AEDs) is indicated for animals with idiopathic epilepsy. Seizures resulting from a structural brain disorder (progressive intracranial disease) require additional therapy, depending on the cause of the disease (e.g., neoplasia or inflammation). AEDs usually are contraindicated for use in animals with extracranial causes of seizures, where therapy should be directed towards the primary cause of the seizures (e.g., hypoglycemia).
The efficacy of an AED depends on its serum concentration, because this determines its concentration in the brain. Therapeutic success can be achieved only when serum concentrations of a given AED are consistently maintained within a therapeutic range.  Therefore, AEDs that are eliminated slowly must be employed. The elimination half-lives of the various AEDs differ considerably between species. Few of the AEDs used for the treatment of epilepsy in people are suitable for use in dogs and cats. This is largely because of differences in pharmacokinetics of AEDs in animals and in humans. Some AEDs are metabolized so rapidly that it is not possible to reach consistently high serum concentrations, even with very high doses. For many AEDs, pharmacokinetic data and/or clinical experience are lacking in cats, a species that usually metabolize AEDs more slowly than dogs.
This lecture will review, contrast, and compare, the current AEDs available for use in cats and dogs.  Recommendations for epilepsy management will be discussed.  An approach to the management of status epilepticus will be included.