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23 Cards in this Set
- Front
- Back
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Epilepsy
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Heterogeneous symptom complex characterized by chronic, intermittent seizures. About 1% pop. Seizure is self-limited episodes of brain dysfunction resulting from abnorma discharge of cerebral neurons.
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Partial seizures and generalized seizures difference
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Partial seizures are focal in nature. Generalizedd are in both hemispheres widely from the onset.
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Partial seizures
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About 60% of seizures. Often from tumors, malformation, trauma, stroke, etc. Simple partial: no unconsciousness. Sensory or motor. Less than 1 min. Complex partial: impaired or loss consciousness. Stereotypical seizure. Longer duration.
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Partial with secondarily generalized seizure
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Simple progresses to generalized tonic-clonic like seizure
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Generalized seizure
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global neocortical discharges that synchronize witih discharges in the thalamus. Most begin in temporal lobes. Absence: abrupt onset of impaired consciousness with staring and cessation of activity. Usually short. Myoclonic: brief shocklike contration.
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Tonic-clonic
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Like partial with secondary generalized but not preceded by a partial seizure.
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How do most antiseizure drugs work?
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They stabilize the inactivated form of the voltage-gated Na channel.
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Phenytoin
(Dilantin) |
Stabilizes closed Na channel. Effective in most seizures other than absence seizure and they exacerbate those. Can get nystagmus with too high of a dose. Can get hirsutism, facial coarsening, gingival hyperplasia
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Drug interactions with dilantin
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Phenobarb and carbemazepine increase hepatic metabolism. Valproate increases serum concentration due to competition.
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Fetal hydantoin syndrom.
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Teratogen from phenytoin. Looks like Fetal alcohol syndrome.
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Carbamazepine
(Tegretol, Carbatrol) |
Stabilizes inactivated Na channel. Used for partial seizures. Diplopia and ataxia common. Most patients have mild leukopenia.
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Valproate
(Depakote, Depakene) |
Stabilizes inactivated Na channel. Also increases presynaptic GABA. Inhibits Ca voltage-gated channels in the thalamus. Effective in generalized seizures of all types particularly myoclonic. Can get mild rise in LFT and need to monitor. Interacts with phenytoin.
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Topiramate
(Topamax) |
Stabilize Na channel. Also potentiate GABA activity. Binding site is distinct from barbs or BDZ. Approved for partial seizures. Sometimes have anxiety reaction. Also visual changes that require withdrawal.
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Lamotrigine
(Lamictal) |
Stabilize Na channel. Inhibit voltage Ca channels. For partial seizures in pediatrics. Can get rash that goes to Stevens Johnson syndrome.
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Zonisamide
(zonegran |
Sodium and calcium channel crap. Only used as adjunct in refractory partial seizures. Get sleepy and fatigued. Depression and psychosis have been reported.
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Phenobarbital
Luminal) and Primidone (Mysoline) |
Enhancement of GABA-mediated Cl- flux. Primidone is metabolized to phenobarbitol. Often tried for every seizure. Prominent sedative activity but only at abnormal levels.
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Tigabine
(Gabitril) |
Inhibits GABA reuptake. Designed drug. Partial seizures is target. CNS depression at high doses. Well tolerated but can get tremor, anxiety or depression.
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Gabapentin
(neurontin) |
Analong of GABA, doesn't interact with the receptors though. Increases GABA levels. Seizures and neuropathic pain is goal of use.
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Vigabatrin
(Sabil) |
Only durg effective in infantile spasms. Inhibits breakdown of presynaptic GABA. Similar to valproic acid???
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Ethosuximide
(Zarontin) |
Inhibits Ca channel in the thalamus. First line drug for absence seizure. Highly effective and preferred over valproate.
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Levetiracetam
(Keppra) |
Used as adjunct for partial seizures. Unknown mechanism. Sedation and dizziness common.
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Felbamate
(Felbatol) |
Treatment of partial seizrues. High aplastic anemia and severe hepatitis.
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Status epilepticus
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Continuous generalized tonic-clonic seizure. Requires supportive care. Give i.v. diazepam or phenytoin. Phenytoin is given after seizure is broken and you need to monitor the heart for arrhythmmia.
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