Exam 6 Flashcards
(137 cards)
Partial Seizure
Begins focally, in a single site in the cortex.
Simple = consciousness preserved
Complex = Loss of consciousness
Generalized Seizure
Involves both cortices from the start
Absence, tonic-clonic, and myoclonic seizures are examples of generalized seizures
Secondary Generalized Seizure
Starts as a partial seizure and then spreads to become generalized
4 Anticonvulsants that Inhibit Na+ Channels in neuron
Carbamazepine Oxycarbazepine Phenytoin Valproic Acid These act by prolonging the "Inactive State" of the Voltage Gated Na Channels COP-V
What types of channels are involved in absence seizures?
T-Type Calcium Channels
2 Anticonvulsants that inhibit T-Type Calcium Channels
Ethosuximide
Valproic Acid
Name 1 GABA reuptake inhibiting anticonvulsant
Tiagabine
Name 1 inhibitor of GABA degradation in the synapse
Vigabatrin
Name three drugs and their classes that have an inhibitory effect on GABA(A) receptors
Phenobarbital (Barbiturate)
Primidone (Barbiturate)
Diazepam (Benzo)
Only 2 drugs effective for monotherapy in treatment of absence seizures
Ethosuximide
Valproic Acid
What were the original anticonvulsants (prior to 1912)? Side effects?
Bromides
Profound sedation and skin lesions
Phenobarbital
Monotherapy for tonic-clonic and partial seizures
Potentiates synaptic inhibition via GABA(A) receptors (agonist of GABA(A) I guess)
Significantly protein bound and metabolized by liver CYP enzymes (drug interactions based on these features)
Induction of CYP enzymes can lead to rapid degradation of other drugs like oral contraceptives ):
Teratogenic
Can cause cutaneous allergic reactions
Primidone
Like Phenobarbital, Monotherapy for tonic-clonic and partial seizures (It’s not as effective though)
Also Potentiates synaptic inhibition via GABA(A) receptors (GABA(A) agonist I guess)
Is metabolized to phenobarbital. The rate at which this happens if variable between patients.
Similar side effects to phenobarbital, but can also cause nausea, dizziness, nystagmus, and ataxia.
Phenytoin
Monotherapy for tonic-clonic and partial seizures (IV fosphenytoin for status epilepticus)
Prolongs Voltage gated Na channels’ rate of recovery from inactive state
Highly protein bound (albumin)
** Plasma concentration increases disproportionately as dosage increases (half-life increases)
Metabolized by CYP enzymes in the liver (drug interactions with Warfarin and oral contraceptives)
Side effect = Gingival hyperplasia in 20%
Stevens-Johnson Syndrome
Drug reaction that causes rash with more than 10% surface area, 5% mortality
Starts with flu-like symptoms, progresses…
Toxic Epidermal Necrolysis is worse (>30% SA, 20-40% mortality)
Carbamazepine
Monotherapy for tonic-clonic and partial seizures
Prolongs Voltage gated Na channels’ rate of recovery from inactive state
Metabolized to 10,11 epoxide, which is just as effective
Induces its own metabolism, making achieving constant plasma concentration difficult
Other anticonvulsants also induce its metabolism
Many side effects.
Induces CYP enzymes = drug interactions (oral contraceptives)
Oxycarbazepine
Monotherapy, adjunctive treatment for partial seizures, even in patients 4-16 years old
Prolongs Voltage gated Na channels’ rate of recovery from inactive state
It’s a prodrug, converted to active metabolite by the liver
Conjugated to glucuronide and excreted
Does not auto induce metabolism
Similar side effects to carbamazepine
Induces CYP, but not as much as carbamazepine
Ethosuxamide
Monotherapy for absence seizures
Inhibits T-Type Ca channels
Not protein bound, few drug interactions
Side effects: nausea, vomiting, anorexia. CNS depression, lethargy. SJS, aplastic anemia.
Valproic Acid
Mono therapy of pretty much all types of seizures
Inhibits T-Type Ca channels, Prolongs Voltage gated Na channels’ rate of recovery from inactive state, and increases GABA synthesis
Highly protein bound, can inhibit certain CYP enzymes and increase hepatic blood enzymes (whatever that means)
Gabapentin
GABA molecule bound to a lipophilic hexane ring
Doesnt act on GABA receptors, but does decrease neuronal activity
Adjunctive treatment for partial seizures, neuropathic pain, and fibromyalgia
Mechanism isn’t really known, it binds to L-type Ca channels, but Ca flow doesnt change.
Not metabolized, excreted in its original form in urine (renal function important)
Side effects: fatigue/ataxia
Lennox-Gustaut Syndrome
Childhood-onset epilepsy Severe cog dysfunction multiple seizure types resistant to drugs Can be deadly Ketogenic diet?
Lamotrigine
Broad spectrum anti epileptic drug (partial and generalized seizures)
Prolongs Voltage gated Na channels’ rate of recovery from inactive state.
Also inhibits Ca channels to some extent
Other AEDs reduce its half life
SEs- dizziness, ataxia, blurred vision, nausea, rash, SJS
Topiramate
Broad spectrum anti epileptic drug (partial and generalized seizures and LGS)
Inhibits Na channels and AMPA-kainate receptors enhance GABA receptors
Not highly protein bound, excreted unmetabolized in urine
SEs- Anorexia, weight loss, fatigue, somnolence
Reduces plasma levels of oral contraceptives
Levetiracetam
Adjunctive treatment for generalized, partial seizures in adults, myoclonic seizures in children.
IV prep for status epilepticus
May prevent synaptic glutamate release???
high safety margin, rapid dose titration, 3-D printing?