Week 12: Anticonvulsants Flashcards
focal onset seizure affects the brain by?
example
one portion/hemisphere
pt is aware but impaired awareness
ie: jerking movements or strange sensations
generalized onset seizure
affects both side of brain and LOC
impaired awareness
tonic clonic, absence
unknown onset seizure
tonic clonic, absence
phenytoin (Dilantin) indications and MOA
tonic clonic & partial complex seizures
MOA: inhibit and stabilize electrical discharges in the motor cortex of the brain by affecting Na ions during nerve impulses
highly protein bound
phenytoin c/c
NO alcohol, bradycardia, 2/3rd degree AV block, syncope
NO preg/lact
caution elderly
ok peds
- caution in hypotension and myocardial insuff,
- renal/hepatic impairment
- sudden withdrawal = rebound status epilepticus
- narrow TI (10-20)
phenytoin ADE
Agitation, dizziness, drowsiness, headache, nystagmus, hypotension, tachycardia, nausea, vomiting, anorexia, altered taste, hypersensitivity reactions (rare), suicidal ideations (rare), blood dyscrasias (rare)
TOXICITY (>20) if ataxia, confusion, dec mental status, lethargy!!!
gingival hyperplasia, discolored urine
after 3-8 weeks of starting dilantin, if get fever, skin rash, lymphopathy…
hypersensitivity syndrome to dilantin (CALL NEURO!)
carbamazepine (Tegretol) indc & MOA
focal and generalized onset of seizures
MOA: affect NA channels, slowing influx of Na in cortical neurons and slowing spread of abnormal activity
carbamazepine (Tegretol) c/c
BBW: Steven johnson syndrome & toxic epidermal necrolysis in CHINESE PTs
(strong HLA-B1202 allele)
screen prior!
BBW: blood dyscrasias (lower WBC, bone marrow = pancytopenia and aplastic anemia)
[get baseline CBC, CMP, TSH before starting]
BBW: dermatologic toxicity
NO preg/lac
carbamazepine (Tegretol) ADE
Agranulocytosis, drowsiness, dizziness, ataxia,
n/v, skin rash, pruritus, constipation, tremor, behavior changes (rare), suicidal ideations (rare), multi-organ hypersensitivity reactions (rare), hepatotoxicity (rare)
carbamazepine (Tegretol) toxic sx’s
HTN, tachycardia, stupor, agitaiton, respiratory depression, nystagmus, urinary retention, seizures, coma
Lamotrigine (Lamictal) indication & MOA
partial seizures, gen tonic clonic
block voltage Na channels
inhibit presynaptic release of glutamate and aspartate in neuron
Lamotrigine (Lamictal) c/c
BBW: serious skin reactions
rebound status epilepticus w/ sudden w/drawal
Ok > 2 years old but increased risk of skin reactions
Lamotrigine (Lamictal) ADE
report any new onset of rash
- Dizziness, headache, GI upset, diplopia, ataxia, insomnia, skin rash
rare: SI, blood dyscrasia, multi-organ hypersensitivity reactions
Lamotrigine (Lamictal) drug to drug interactions
combined oral contraceptives (decrease lvls of lamictal)
zonisamide indic & MOA
partial seizures
blocks voltage dependent Na and Cl channels
zonisamide ADE
Somnolence, anorexia, dizziness, headache, agitation, memory difficulties, aplastic anemia (rare), agranulocytosis (rare)
decrease sweating = hyperthermia = worse in peds pts
zonisamide c/c
NO SULFA!!!!!
rebound seizures
NO preg/lac
ok > 16 yrs old
Succinimides: ethosuximide, methsuximide
indication & MOA
indc: absence seizure
MOA: decrease nerve impulses and transmission in motor cortex
Succinimides: ethosuximide, methsuximide ADE
GI distress sedation ataxia, lethargy, headache, rash, pruritus, mood changes Lupus sx’s Narrow TI
Toxicity: CNS depression, resp depression, acute n/v
Don’t take with alcohol!
Decrease birth control - use backup method
Succinimides: ethosuximide, methsuximide c/c
monitor during preg
rebound seizures
> 3 yrs old ok
valproic acid indic & MOA
focal/partial seizures, generalized seizures, focal onset impaired awareness, absence
increases and enhances GABA, mimics action at postsynaptic sites
blocks voltage dep NA channels = suppression of high freq, repetitive neuronal firing
valproic acid ADE
Headache, drowsiness, dizziness, nausea, vomiting, tremor, visual disturbance, weight gain, behavioral changes, hypersensitivity reactions (rare), SI (rare), brain atrophy (rare)
Narrow TI
Toxicity: CNS depression, confusion, jaundice
valproic acid c/c
BBW: hepatotoxicity
BBW: severe pancreatitis
NOOOO Preg!
rebound seizures
NO elderly (beers)
gabapentin ind & MOA
focal seizures
GABA analogue that bind to brain receptors
doesn’t bind/mimc GABA
gabapentin ADE
Dizziness, drowsiness, fatigue, ataxia, peripheral edema, abnormal thinking
Neuropsychiatric events in 3-12 year olds
Suicidal ideation
gabapentin c/c
Only if benefits outweigh risks in pregnancy and lactation Caution in renal, elderly Somulence Caution substance abuse hx Rebound seizures
topiramate (Topamax) ind & MOA
Focal seizures, primary generalized tonic-clonic seizures
Migraines and cluster h/a
block NA channels or potentiate GABA
topiramate (Topamax) ADE
Ataxia, paresthesia, dizziness, somnolence, difficulty concentrating, mood changes, weight loss
SI (rare)
Decrease sweating and hyperthermia
Oligohidrosis / hyperthermia
topiramate (Topamax) c/c
NO preg
no < 3 months
caution renal, hep, elderly
rebound seizures
levetiracetam (Keppra) ind & MOA
focal onset seizures, generalized onset seizures
inhibit burst firing w/o affecting normal neuronal excitability
levetiracetam (Keppra) ADE
Somnolence!! dizziness, somnolence, nervousness, mood disturbances, SI (rare)
Rare dermatologic reactions and blood dyscrasias
levetiracetam (Keppra) c/c
fewer drug2drug intxn bc NOT met by P450 sys
rebound seizures
children inc risk of psychiatric sx’s
