Anti-Seizure Flashcards
Oldest anti-seizure drug; chronic use is limited by its sedating effects & potential for lethal overdose
Phenobarbital
Phenobarbital use in seizures (2)
Terminate refractory status epilepticus, neonatal seizures
Benzodiazepine use in seizures (1)
Used IV to terminate status epilepticus
Which benzodiazepine, if any, is preferred to treat seizures?
Lorazepam due to its longer duration of action (single dose dependent on re-distribution!!!!)
BZDs use in seizure treatment long-term
Associated with tolerance, limited usefulness
T/F: As a group, new anti-seizure agents are slightly more efficacious and better tolerated than traditional agents.
False- equally efficacious
T/F: Most new anti-seizure agents do not inhibit/induce CYPs and thus have fewer drug interaction
True
MOA= may increase GABA release, blocks HVA Ca++ channels (—> which may suppress glutamate release)
Gabapentin
Does gabapentin access the BBB? If so, how?
Yes, L-amino acid transporter
How is gabapentin excreted?
Unchanged in the urine
Gabapentin use for seizures (2) #1: add-on or monotherapy #2: focal? #3: generalized - what types?
Add-on for focal and generalized seizures (doesn’t specify which ones)
Uses of gabapentin besides being an add-on for focal and generalized seizures include the following EXCEPT:
A. Postherpetic neuralgia & neuropathic pain
B. Migraine
C. Fibromyalgia
D. Binge eating & bulimia
E. Bipolar disorder
D (off-label for topiramate)
ADEs: mostly well-tolerated
Sedation, dizziness
Gabapentin
Major MOA of lamotrigine
Blockade of Na+ channels, leading to reduced release of glutamate (from presynaptic neurons)
MOA= Ca++ channel block, 5-HT3 antagonist
Na+ blockade, leading to reduced release of glutamate
Lamotrigine
PK: metabolism of lamotrigine A. Glucuronidation B. Excreted unchanged in the urine C. Not a substrate or inducer for CYPs (mostly devoid of DDIs) D. Metabolized by 3A4 to active epoxide
A (rate of hepatic clearance is increased by enzyme inducers)
Uses= Lennox-Gastaut syndrome (multiple refractory seizure types, mental retardation)
Lamotrigine (adjunct is topiramate)
Lamotrigine use for seizures #1: add-on or monotherapy #2: focal/partial? #3: secondarily generalized - types? #3: generalized - what types?
Lamotrigine use for seizures #1: add-on or monotherapy #2: focal/partial? #3: secondarily generalized - types? #3: generalized - what types?
Alternative to ethosuximide for absence seizures: A. Gabapentin B. Lamotrigine C. Levetiracetam D. Tiagabine
B (lamotrigine)
Uses besides those for seizures of lamotrigine
Bipolar disorder maintenance (reduces depressive episodes)
All AEs: dizziness, ataxia, blurred vision, N/V
Teratogen
Rash/SJS (BBW)
Lamotrigine
Boxed warning of lamotrigine
Rash/SJS early in therapy
T/F: A pregnant woman can take lamotrigine for her secondarily generalized tonic-clonic seizures.
False- teratogenic
MOA: unknown…binds to presynaptic vesicle protein SV2A & may impede impulse conduction
Levetiracetam (no evidence of effects on ion channels or GABA/glutamate)
T/F: The PK of new anti-seizure agents is less complex, except for levetiracetam.
False- levetiracetam is not bound to plasma proteins and is mostly devoid of DDIs (not a substrate/inducer for CYPs
Levetiracetam seizure use: #1: add-on or monotherapy #2: focal/partial? #3: secondarily generalized - types? #3: generalized - what types? (Absence, myoclonic, tonic-clonic, status epilepticus)
Add-on, partial or generalized tonic clonic & myoclonic seizures (3 types)
Common ADEs: well-tolerated generally
Fatigue, dizziness, hypertension
Levetiracetam
Serious ADEs of levetiracetam
Behavior symptoms (agitation, hostility, depression, depersonalization)
MOA of tiagabine
Blocks presynaptic and glial GABA reuptake transporter GAT-1 (prolongs inhibitory effect of GABA)
Use= add-on for refractory partial seizures with/without secondary generalization
Tiagabine (blocks GABA reuptake)
Off-label use of this anti-seizure agent is discouraged - may promote seizures in patients without epilepsy
Tiagabine (enhances 3-Hz spike & wave discharges in absence seizures)
Which of the following are correct ADEs of tiagabine?
A. Renal calculi, bilateral vision loss
B. Tremor, somnolence
C. Cognitive impairment (esp. in children), N/V
D. Hypertension, dizziness
B
Which of the following are ADEs of tiagabine? Select all that apply.
A. Bilateral vision loss
B. Rash/SJS
C. Dizziness
D. Enhanced 3-Hz spike-and-wave discharges in absence seizure patients
C and D
MOA: Blocks Na+ channels
Neuronal membrane hyperpolarization (K+)
Enhances postsynaptic GABAa-receptor currents
Limits activity of glutamate receptors
Topiramate (Topamax)
MOA includes weakly inhibiting carbonic anhydrase
Topiramate (metabolic acidosis in CNS)
Seizure use of topiramate: #1: add-on or monotherapy #2: focal/partial? #3: secondarily generalized - types? #3: generalized - what types? (Absence, myoclonic, tonic-clonic, SE)
Monotherapy, partial & generalized tonic-clonic (2!) (also adjunct for Lennox-Gastaut)
Adjunct for Lennox-Gastaut syndrome
Topiramate
Uses: prophylaxis of migraine A. Tiagabine B. Lamotrigine C. Levetiracetam D. Topiramate
Topiramate (Topamax)
Which of the following does NOT have migraine listed as a non-seizure use? A. Topiramate B. Levetiracetam C. Valproate D. Gabapentin
B (no non-seizure use stated- partial or generalized tonic-clonic & myoclonic)
Which of the following is NOT an off-label use of topiramate (as listed in the handout)?
A. Bipolar disorder
B. Cluster headaches
C. Neuropathy
D. Binge eating & bulimia
E. Off-label use is discouraged - may promote seizures in patients without epilepsy
A (also weight loss!, E is tiagabine btw)