Seizure Tx: AED Flashcards
Seizure Introduction
Seizures affect approx 40 million people worldwide and 2 million people in the US
1% of the US population is affected
20% - etiology known (brain trauma, tumor, stroke, infection)
80% - etiology unknown
Anti epileptic drugs (AEDs) are #1 treatment
Types of partial seizures
Partial Seizures: Seizures begin locally
Simple: Without impairment in consciousness
Complex: With impairment in consciousness
Secondary generalized: Partial onset evolving into GTC
Types of generalized seizures
Generalized Seizures: Bilaterally symmetrical and w/out local onset
Tonic-clonic: Grand mal
Absence: Petit mal
Myoclonic
Atonic
Epilepsy syndromes
Infantile spasms: Occurs in infants <1yr old, often develop other seizure types later in life
Lennox-gastaut syndrome: Combo of generalized seizure types, cognitive dysfunction
Status Epilepticus
Continuous seizure activity lasting >30 minutes OR two or more seizures w/out return of consciousness in between
Epilepsy Pathophysiology
Sudden electrical disturbance of the cerebral cortex (CNS); Group of neurons fire rapidly and repeatedly for seconds or minutes; Likely related to excess excitatory neurotransmitters, failure of inhibitory neurotransmitters, or combo (imbalance between excitatory and inhibitory)
Goals of therapy
Control or reduce the frequency of seizures
Ensure adherence
Optimize quality of life
Balance between seizure control and side effects
General Treatment Approach
- Determine risk of subsequent seizure: Risk factors include structural CNS lesion, abnormal EEG, partial seizure type, positive family history, and postictal motor paralysis
- AED selection determined by seizure type, adverse effect profile and patient preference
- Begin w/monotherapy: 550-70% can be maintained on one AED
- Titrate dose as needed, depending on seizure control, AE
- Adherence is KEY: up to 60% of pts w/epilepsy are nonadherent–>treatment failure (AE, don’t have seizures all the time; adolescents have the highest non-adherence)
Non-pharmacologic Therapy
- Surgery
- Temporal lobectomy
- Corpus Collosum section
- Hemispherctomy - Vagal nerve stimulator implantation: Regular pulses of electrical energy to prevent or interrupt electrical disturbances; Thin, round pulse generator implanted under the skin on the upper left side of the chest; Electrodes connect to the left vagus nerve on the left side of the neck; Costly ($15,000) but has “medication sparing” effect; Can cause hoarseness and cough
- Ketogenic Diet: High fat, no carbs; Induces state of ketosis which decreases seizures
- Modified Atkins Diet for kids
AEDs Mechanism of Action
Effect sodium and calcium channels –>stabilization of neuronal membranes
Enhance inhibitory neurotransmission (GABA)
Decrease excitatory neurotransmission (Glutamate and Aspartate)
–>Increase seizure threshold
–>Inhibition of the spread of abnormal (seizure) discharges
Therapeutic Range
Serum concentration that controls seizures w/out causing concentration-related AE
Population data used to determine range
Personal therapeutic range for each patient
Concentration-Related AE
Most common
Increased drug levels results in increased side effects
Not permanent
See at “peak” concentration or throughout day
Management:
-Lower dose/level
-Change schedule or formulation of medication: take more often at lower dose or take ER form
-D/C med
Idiosyncratic AE
More rare Not related to dose/level May be permanent Seen throughout day Management: -D/C med -Treat adverse reaction as needed
Types of AE
Concentration-Related
Idiosyncratic
AEDs and Suicide Risk
- Patients taking AEDs seem to have TWICE the risk of suicidal thoughts and behaviors as those not taking the drugs
- Reason for increased risk is unknown
- Relative risk appears higher in patients treated for seizure disorders compared to migraines, BDP, or other conditions
- Patients w/epilepsy already have a higher risk of depression and a THREE-fold higher risk of suicide
- Risk is small, but patients should be educated to seek help if suicidal thoughts or behavior occur
