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Pharmacoresistant 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
1Lhatoo SD, et al. Epilepsia.
2000;41:1592-1596.
2Krakow K, et al. Neurology. 2001;56:1772-1774.
3Hersdorffer.DC, et al. Ann Neurol. 2000;47:246-249.
4Harden CL, et al. Epilepsy Behav. 2000;1:93-99.
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