Seizure Pharmacotherapy

• Factors that indicate initation of anti seizure medications

  Consider unprovoked vs provoked seizure

  • Unprovoked: unknown etiology or related to brain lesion or progressive nervous system disorder
  • Provoked: toxic or metabolic disturbance, head trauma, acute stroke
• Reasons to treat first time seizure

  • CNS abnormality like brain tumor or scar tissue from previous head injury
  • Consider treating a provoked seizure until the main reason for the seizure has resolved (metabolic, infection, trauma, TBI)
• Starting therapy after 1st vs 2nd seizure

  Treat 2 or more unprovoked seizures that occur more than 24 hours apart, PCP should consult/refer to Neurologist to initiate or alter medication, monitor electrolytes and drug levels

  • Start after 1 seizure if at risk for subsequent seizure
• Hepatic enzyme INHIBITORS

  Valproate, so warfarin would be SUPRAtherapeutic
• Hepatic Enzyme INDUCERS

  Phenytoin, Phenobarbital, Carbamazepine, Felbamate, Topiramate, Oxcarbazepine

  • So warfarin would be SUBtherapeutic
• What drugs interfere with hepatic inducers

  statins, CCB, SRNIs, antipsychotics, TCAs, hormonal contraception, warfarin, anti-cancer drugs
• Aging and selecting medications

  Elderly likely have alterations in protein bindings, reduced hepatic metabolism, diminished renal clearance, polypharmacy, neuro side effects
• Medications in RENAL disease

  Adjust doses of gabapentin, topiramate, levetiracetam, oxcarbazepine, pregabalin
• Medications in HEPATIC disease

  Avoid these bc they're associated w/ hepatic toxicity = phenytoin, carbamazepine

  • Adjust dose of lamotrigine, phenobarbital, levetiracetam, gabapentin, pregabalin, and the 2 above
• Adverse effects of seizure medications

  • Neurocognitive: HA, dizziness, memory, cerebellar function, most have negative impact
  • Hypersensitivity: SJS and TEN in phenytoin, carbamazepine, oxcarbazepine, lamotrigine
  • Suicidality, weight gain or loss
• Consider switching from generic to trade brand as potential cause of breakthrough seizure
• Increase compliance by having patient take the medication less often
• Medications for special populations

  • Hormonal contraception: explore non-hormonal contraceptive options w/ PCP and OBGYN
  • Women in childbearing years: Folate rx always if on anti-seizure med (helps neural tube develop), counsel on teratogenic effects (valproate is major for malformations)

  1. Levetiracetam, Lamotrigine, Oxcarbazepine may be best choice

  • Pediatrics: refer to special pediatric neurologists
• Patient counseling for medications

  Start with monotherapy, titrate up gradually

  • Educate about disease and follow up
  • Decrease alcohol use (b/c lowers seizure threshold)
  • Have seizure calendar (record seizure and drug doses)
  • Discuss triggers (alcohol use, fatigue)