Chapter 73: Epilepsy

KEY CONCEPTS

• The goal of pharmacotherapy is seizure freedom with minimal side effects, and two-thirds to 80% of patients can achieve this.

• Accurate classification and diagnosis of seizure type/epilepsy syndrome, including where seizures begin, is critical to selection of appropriate pharmacotherapy.

• Besides seizure type, antiseizure drug (ASD) selection depends on patient characteristics such as age, gender, ethnicity, susceptibility to side effects, comorbid conditions, ability to adhere with the prescribed regimen, presence or absence of insurance coverage, and need for therapeutic levels to be reached quickly.

• Pharmacotherapy of epilepsy is highly individualized and requires titration of the dose to optimize ASD therapy (maximal seizure control with minimal or no side effects).

• If the therapeutic goal is not achieved with monotherapy, a second ASD, preferably with a different mechanism of action, can be added, or the patient’s ASD can be switched to an alternative single agent.

• Patients who do not respond to drug therapy should be referred to a comprehensive epilepsy center to determine if nonpharmacologic treatments such as surgery are potential options.

• In general, first-generation ASDs are very efficacious but have complex pharmacokinetics, multiple drug–drug interactions, and an increased incidence of adverse effects that in general make them more complicated to manage than either the second- or third-generation ASDs.

• Second-generation ASDs have unique mechanisms of action and are as efficacious as first- and third-generation ASDs with better tolerability, and are therefore generally considered first in epilepsy pharmacotherapy.

• Third-generation ASDs should be reserved for failure of other agents due to cost and limited long-term experience.

• Despite numerous drug trials, 20% to 35% of patients will have unsatisfactory control with ASDs and will be considered to be drug-resistant.

Patient Care Process for Epilepsy

Collect

• Patient-specific demographics such as age, race, and gender

• A detailed description of seizure semiology from the patient and a witness of the seizure, including the following:

  • Degree of mental status impairment during the event

  • Presence of ictal motor, sensory, autonomic, or other features at onset of the seizure (Fig. 73-1)

  • Tongue biting, cheek biting, and bladder or bowel incontinence during the seizures

  • Seizure time course and any postictal phenomena (eg, fatigue, headaches, confusion, and psychosis)

• Frequency of seizure events and any precipitating factors

• Information on comorbid medical psychiatric, and neurodevelopmental conditions including depression, anxiety, and learning and development

• Family history of epilepsy, risk factors for epilepsy including injury at birth, history of meningitis or encephalitis, history of traumatic brain injury

• Current and past medications including antiseizure drugs (ASDs)

• Duration of past ASD therapy and response to each ASD (eg, decrease or increase in seizure frequency and side effects experienced)

• Allergies to medications including ASDs

• Laboratory values for electrolytes and glucose to ...