Antiseizure drugs Flashcards
What is a seizure?
transient disturbance of cerebral function due to an abnormal paroxysmal neuronal discharge in the brain.
Dif. between epilepsy and seizures?
duration of sxs
Epilepsy: chronic, recurrent
Seizures: finite, resolves
What are the 2 classifications of epileptic seizures?
focal seizures
generalized seizures
What is a focal onset seizure?
formerly partial seizure
start in an area or network on one side of the brain
What is a generalized onset seizure?
affects both sides of the brain or large networks of cells on both sides from the beginning
doesn’t need to involve entire brain
What is an unknown onset seizure?
if the beginning of seizure is not clear/observed
Generalized absence seizure
consciousness impaired briefly
almost always begin in childhood, freq. cease by 20 y/o
What are the types of focal seizures?
focal aware, focal impaired awareness, focal to bilateral tonic clonic
define focal aware seizure
no change in person’s awareness
define focal impaired awareness
awareness is impaired during a focal seizure
define focal to bilateral tonic clonic seizure
focal seizure may start in one part of the brain with the person aware or with impaired awareness
spreads to involve both sides of the brain and person unaware during the seizure
What is preferred in tx of seizures?
monotherapy
When should ASDs be initiated?
in pts who have had two or more unprovoked seizures
What are some drugs that lower seizure threshold?
theophylline, alcohol, high dose phenothiazines, antidepressants, street drugs
When to consider stopping ASDs?
seizure free 2-4 yrs
complete seizure control within 1 yr
onset of seizure btwn 2-35 yrs old
+ normal neuro exam and EEG
What are the 3 proposed MOA of seizure drug therapy?
- enhancement of GABAergic (inhibitory) transmission
- Decrease excitatory (usually glutamatergic) transmission
- Modification of ionic conductance
Ethosuximide only works for..
Absence seizures
What drugs can be used in the tx of general absence seizures?
Ethosuximide**
Lamotrigine
Valporic acid
What drug alternatives can be used for refractory absence?
Clonazepam
Topriamate
MOA of Ethosuximide?
Decreases VG-Ca2+ currents decreases glutamate
ADEs of ethosuximide?
HA, blood dyscrasias, GI distress, drowsiness, rash
chronic: behavior changes
Lamotrigine MOA?
Blocks Na+ and Ca2+ channels, decreases glutamate
What can Lamotrigine be used for?
Generalized tonic-clonic
Focal aware/impaired
Focal or Generalized
Myoclonic
Generalized Absence
Box warning for Lamotrigine?
serious skin rash- start low and go slow, diplopia
Other ADEs: HAs, dizziness
Valporic acid MOA?
Alters synthesis and degradation of GABA
What can valporic acid be used for?
Generalized tonic-clonic
Focal aware/impaired
Focal or Generalized Myoclonic
Generalized Absence
Black box warning for Valporic Acid?
hepatotoxicity, teratogenic, pancreatitis, alopecia
other sxs: alopecia, nausea, weight gain
Dont give to women of child bearing age
What meds are FDA approved for tonic clonic seizures?
Topiramate- US guidelines
Lamotrigine
Levatriacetam
Perampanel
What meds are ineffective in absence seizures?
Phenytoin
Phenobarbitol
What meds can aggravate absence seizures & therefore should be avoided?
carbamazepine
vigabatrin
gagapentin
tiagabin
ADE of clonazepam?
Sedation
ADEs of topiramate?
Cognitive slowing, confusion
Carbamazepine box warning?
Serious derm rxns
HLA-B*1502 allele (TEN, SJS) in Asians
Aplastic anemia, agranulocytosis
Ataxia, diplopia, hyponatremia, MBD (Vit D & Ca)
What drug can increase PR interval?
Lacosamide
What med induces its own metabolism?
Carbamazepine
ADEs of phenytoin?
Ataxia nystagmus gingival hyperplasia hirsutism neuropathy folate deficiency, MBD
Phenytoin box warning?
Cardio risk associated w/ rapid infusion
ADEs of phenybarbitol?
Sedation
Intellectual blunting
MBD
Behavior changes
ADEs of both gabapentin & pregablin (Lyrica)?
Ataxia
Somnolence
Wt gain
Vigabatrin box warning?
Permanent vision loss
Perampanel box warning?
Serious psychiatric & behavioral rxns
ADEs of tiagabine?
Concentration & attention difficulties
Behavioral disturbances
Increased appetite
ADEs of levetiracetam?
Behavioral problems
HA
ADEs of zonisamide?
Cognitive slowing
Paresthesia
Rash-sulfa based drugs
Kidney stones
Oligohydrosis
What drugs interact w/ phenytoin?
Fluoxetine
Fluconazole
Digoxin
Isoniazid
OCPs
What drugs interact w/ phenobarbitol?
Nifedipine
Theophylline
Verapamil
What drugs interact w/ rifampin?
valporate & euthosuximide
What drugs interact w/ carbamazepine?
Fluoxetine
Verapamil
Macrolides
Isoniazid
What drug interacts w/ lamotrigine?
Sertraline
What drugs interact w/ topiramate?
OCPs
Lithium?
