VNS Therapy for Epilepsy

Treatment barriers

Refractory epilepsy with uncontrolled seizures is sometimes prolonged unnecessarily. Barriers to effective care may include diagnostic issues, therapeutic issues, continuation rates, comorbid illnesses, and communications issues.

  1. Diagnostic Issues
    An accurate, early diagnosis is also important to avoid prolonged pharmacoresistant epilepsy. Establishing whether a seizure has occurred and identifying the type of seizure(s) or epileptic syndrome will direct the choice of therapy. Misdiagnosis may lead to suboptimal treatment, which can allow uncontrolled seizures to continue.
  2. Therapeutic Issues
    Pharmacoresistance is more likely if the first medication has an intolerable side effect profile because it takes time to try additional medications and because side effects may lead to nonadherence.
  3. Continuation Rates
    Studies have demonstrated that many patients discontinue AED therapy over time, presumably when AEDs become ineffective, intolerable, or both. Lhatoo et al found the 3-year retention rate to be less than 50% for topiramate and less than 30% for lamotrigine and gabapentin.1 Another study by Krakow et al evaluated continuation rates of levetiracetam, which were shown to decline substantially over time. The estimated continuation rates were 60% at 1 year, 37% at 3 years, and 32% at 5 years.2 Patients who repeatedly discontinue various AED regimens may have pharmacoresistant epilepsy.
  4. Comorbid Illnesses
    Comorbidities can contribute to treatment outcomes. Depression, for instance, appears to have a synergistic relationship with epilepsy and may be associated with a six-fold increased risk for the development of unprovoked seizures.3 Furthermore, coordination of care is essential when patients with epilepsy have other coexisting illnesses.4
  5. Communication Challenges
    Establishing open communication and discussing all issues related to quality of life, safety and tolerability, and seizure control are essential to building a physician-patient relationship that will optimize care and satisfy the therapeutic needs of the patients. Communication should include patient education with regard to all available and appropriate care options. When it is evident that a patient is experiencing pharmacoresistance, nonpharmacologic options should not be delayed because uncontrolled seizures could persist longer and possibly have deleterious effects.

“The data indicate that earlier identification of appropriate candidates for VNS (ie, after 2 or 3 medicine failures and duration of epilepsy of less than 2 years) would enhance seizure control and subsequent quality of life.”

Renfroe and Wheless, 2002

1 Lhatoo SD, et al. Epilepsia. 2000;41:1592-1596.

2 Krakow K, et al. Neurology. 2001;56:1772-1774.

3 Hersdorffer.DC, et al. Ann Neurol. 2000;47:246-249.

4 Harden CL, et al. Epilepsy Behav. 2000;1:93-99.

Refractory Epilepsy