Epilepsy Flashcards
How have most drugs for the CNS been discovered?
Serendipity
What is Carbamazepine and what does it do?
Anti-seizure drug
DRUG OF CHOICE
Blocks Sodium Channel by forcing it into the inactivated state
“use-dependent block”
INDUCES MICROSOMES
meaning it increases metabolism of itself and other drugs
What is Phenytoin and what does it do?
Anti-seizure drug
Blocks Sodium Channel by forcing it into the inactivated state
“use-dependent block”
A few MAJOR pharmacokinetic drawbacks
Zero order kinetics, No two patients are the same
Binds to plasma proteins (Interactions with eg aspirin)
Gingival hyperplasia and hirsutism
What is ehosuxamide and what does it do?
Anti-seizure drug
Only alleviates absence
Inhibits a CERTAIN KIND of Calcium channel found in reciprocal connections between cerebral cortex and thalamus
What is phenobarbital and what does it do?
Anti-seizure drug (Less effective, barbiturate, more for historical interest) Hepatic microsomes O/D Sedation Teratogen
What is diazipam and what does it do?
Anti-seizure drug
Drug of choice in “status epilepticus” (secret fifth seizure)
Don’t use chronically
Doesn’t inhibit calcium channel, but still treats absence (somehow)
What is Valproate and what does it do?
Anti-seizure drug
Blocks Sodium Channel by forcing it into the inactivated state
AND
Inhibits GABA-T (i.e. inhibits breakdown of GABA)
ALSO inhibits Thalamic Ca2 channels
“use-dependent block”
What are the two basic kinds of seizure? What is the difference?
Focal onset and Generalized onset Focal onset: - focus in one hemisphere - Conscious - May become generalized
Generalized:
- Both hemispheres
- Unconscious
- Cortex
What are the two types of Focal epilepsy?
Focal Aware
Focal Impaired Awareness
What are the symptoms of a focal aware seizure?
No generalized symptoms, depend on where focus is
What are the symptoms of a focal aware seizure?
No generalized symptoms, depend on where focus is
What are the symptoms of Impaired awareness seizures?
Usually affects temporal lobe Consciousness is lost or impaired Preceded by aura Simpal "automatisms" or complex "psychomotor attack" Most common subtype of epilepsy
eg. following woman in park, doing a pirouette, smacking lips, etc
What are the two types of Generalized seizure?
Tonic-Clonic
Abscence
What are the symptoms of Tonic-Clonic Seizure?
“Grand mal”
Tonic phase for 30 seconds, all muscles contracted
Clonic phase for 1-3 minutes, back and forth contraction
Post-ictal phase, recovery (most patients sleep)
What are symptoms of absence seizure?
“petit mal” loss of consciousness, looks like internet got cut
When is consciousness lost for the 4 different types of seizure?
Aware: never
Awareness impaired: never but impaired
Tonic-clonic: Immediately lost
Absence: immediately lost
When is consciousness lost for the 4 different types of seizure?
Aware: never
Awareness impaired: never but impaired
Tonic-clonic: Immediately lost
Absence: immediately lost
What is characteristic about the EEG of an absence seizure?
3 Hz “spike and wave”
True/False? Focal Aware seizures are visible on EEGs on one side only
True
What does a scalp EEG measure?
Pyramidal cell activity
If cortical cells fire enough, activity passes through cells
True/False? Most types of epilepsy are inherited
False, only some
True/False? Most types of epilepsy are inherited
False, only some
What is the main symptom of epileptic brains (what has been observed in the past 20 years of research)
Chennelopathies (acquired or inherited)
Mutations in voltage gated Na and K channels
True/False? Bromides cure epilepsy
False. They treat epilepsy
There is no cure for epilepsy
True/False? Bromides cure epilepsy
False. They treat epilepsy
There is no cure for epilepsy
Describe the GABA synapse
Glutamate is converted to GABA at the presynapse GABA is released Acts on GABA-A receptors Reuptaken by GABA uptake carriers Broken down by GABA-T(ransaminase)
True/False? Drugs for focal seizures also work for tonic-clonic seizures
True (basically)
Name the only anti-seizure drug with that doesn’t inhibit focal or tonic/clonic seizures
Ethosuxamide
Can increased GABA explain Valproate and Ethosuxamide (and BZs) effect on absence seizures?
No
Can increased GABA explain Valproate and Ethosuxamide (and BZs) effect on absence seizures?
No
How are Benzodiazepines like Diazepam used for anti seizure?
Drug of choice in “status epilepticus” (secret fifth seizure)
Don’t use chronically
Doesn’t inhibit calcium channel, but still treats absence (somehow)
What does vigabatrin do?
Anti-seizure drug
Inhibits GABA-T
viGABATrin
What kind of channel is the AMPA glutamatergic receptor?
Glutamate ligand-gated ion channel
Binds glutamate and lets Na in
What is the side effect of drugs that treat siezures via NMDA receptor block?
Ataxia
Should you discontinue Anti-seizure drugs during pregnancy?
you SHOULD, but only if possible
If not possible, try monotherapy at minimal effective dose
