AEDs Flashcards
Treatment of seizures typically tries to affect what 2 transmitters?
decreased effectiveness of GLU
increase effectiveness of GABA
What is the mechanism of action for carbamazepine?
It stabilizes the “inactivated” state of VG Na+ channels to decrease repetitive firing
What is the main therpauetic use of carbamazepine?
grand mal seizures
What are some side effects of carbamazepine
- diplopia
- gait instability
- inducer of cyp450
What is the mechanism of action for ethosuximide?
It blocks the T-type voltage gated calcium channels in postynaptic thalamic neurons
What is the main therapeutic use of ethosuximide?
absence seizures
What are the side effects of ethosuximide?
GI distress
fatigue
headache
dizziness
What is the mechanism of action for levetiracetam?
It affects synaptic vesicle protein (SV2A), resulting in decreased GLU release, but increased GABA release!
What is the main therapeutic use of leviteracitam
partial seizures
What is the kinetic order for levitiracetam?
zero order
What are some side effects of levetiracetam?
headache
somnolence
dizziness
asthenia
What is the mechanism of action for topiramate?
increased inactivation of VG Na+ channels
- blocks presynaptic type N and typ P/Q VG Ca2+ channels
What is the main therapeutic use for topiramate?
partial and generalized tonic-clonic seizures.
great for monotherapy
What are some side effects of topiramate?
parasthesias, anorexia, idiosyncratic glaucoma, stones, cognitive slowing
What is the mechanism of action for phenytoin?
It prolongs the inactivation of VG Na+ channels, preventing rapid firing of action potentials
What is the main therapeutic use for phenytoin?
Generalized tonic clonic seizures
status epilepticus
What is critical to know about the pharmacokinetics of phenytoin?
It has zero order kinetics, so when the metabolizing enzymes are saturated, even small dose changes will cause large changes in drug concentration, increasing toxicity without added benefit
so if phenytoin isn’t working for someone, just switch them to a new drug - don’t increase dose
What are some side effects of phenytoin?
nystagmus, diplopia
ataxia
sedation
induction of cyp450 and protein binding leads to drug interactions
What is the mechanism of action for tiagabine?
Inhibits reuptake of GABA via GAT1, thus increasing the amount of GABA available to postsynaptic neurons
What is the therapeutic use for tiagabine?
partial seizures
What are the size effects of tiagabine?
nervousness
dizziness
depression
seizures
What is the mechanism of action for valproic acid?
blocks VG Na+ channels, blocks NMDA receptors, decreases GABA reuptake
What is the main therapeutic use for valproic acid?
absence seizures - especially when combined with some generalized tonic/clonic
What are the main side effects of valproic acid?
GI upset
Drug interactions with other anticonvulsants because it decreases liver metabolism
Hepatotoxicity - can be fatal
Teratogenic (inhibits HDAC)
