Narrow Spectrum Antiepileptic Drugs

Question 1

narrow spectrum antiepileptic names

Answer 1

carbamazepine (classic car), phenytoin (tow truck), phenobarbital (barber shop), gabapentin (grab a pint ice cream truck)

Question 2

what narrow spectrum antiepileptics treat

Answer 2

focal seizures (focal arm shaking of the waitress) and generalized tonic clonic seizures

Question 3

dont want to use narrow spectrum antiepileptic with what seizures

Answer 3

juvenile myoclonic epilepsy (JME)
can exacerbate these seizures
not effective for absence seizures

Question 4

how narrow spectrum antiepileptic work

Answer 4

carbamazepine and phenytoin increase Na channel inactivation phase
gabapentin blocks voltage gated Ca channels (closed calci-yum ice cream cooler)

Question 5

carbamazepine uses

Answer 5

first line treatment for trigeminal neuralgia (three gems) - sudden and sever stabbing/electric shock, unilateral for a few seconds pain in CNV (V2/V3) distribution

Question 6

narrow spectrum antiepileptic side effects

Answer 6

*dose dependent
ataxia (falling plates and ice cream)
carbamazepine and phenytoin cause diplopia (crossed headlights), induce CYP-450 (license plates), drug reaction with eosinophilia and systemic symptoms/DRESS syndrome 2-8 weeks after initiation (dress with pink spots on waitresses), and stevens-johnsons syndrome (SJS/TEN) within 8 weeks of therapy (sloughed off masks), and drug induced lupus (wolf)

Question 7

carbamazepine specific side effects

Answer 7

syndrome of inappropriate ADH (SIADH) - caused by increased responsiveness of collecting tubules to ADH creating dose related hyponatremia (ADH on the guys head)
aplastic anemia and agranulocytosis are fatal within 3-4 months of initiation, counts less than 3,000 (WBC) or 1,000 (PMNs) = decrease dose and WBC monitoring or discontinue (sand timer)
teratogenic causing neural tube defects/spina bifida (spider on guys shirt and neural exhaust tube)

Question 8

phenytoin specific side effects

Answer 8

folate deficiency causing megaloblastic anemia - clinical importance is unknown (spilled salad)
gingival hyperplasia 50% of people after 3-4 months of therapy b/c increased PDGF = proliferation of gingival cells and alveolar bone (expanding gum)
hirsutism (big bushy beard)
teratogenic causing cleft palate, cardiac, and genitourinary malformations (spider on guys shirt and cleft trucker hat), decreased bone density b/c induction of CYP-450 and increased vit. D catabolism (fractured bone axle on car)

Question 9

how to treat status epilepticus

Answer 9

acute: IV benzodiazepines (diazepam, lorazepam) (Ben’s diner)
maintainenece: IV phenytoin/phosphenytoin (tow truck under Ben’s diner)

Question 10

how to treat treatment refractory seizures

Answer 10

IV phenobarbital can control most seizures, but high doses cause sedation, and reduce BP and RR (barbiturate) - barber shop

Question 11

gabapentin uses

Answer 11

add on therapy for refractory focal seizures
chronic neuropathic pain (frayed wire), painful diabetic neuropathy (sweets on truck), fibromyalgia (fiber bars), post-herpetic neuralgia from reactivated VZV (zeus and lightning bolt)

Question 12

vigabatrin and tiagabine

Answer 12

narrow spectrum antiepileptics that increase GABA (raised GABA cab)
vigabatrin by irreversibly inhibiting GABA transaminase (V cab transmission)
tiagabine by inhibiting GABA reuptake (tied up cab driver)
used as adjunctive treatment for partial seizures

Question 13

SJS/TEN risk

Answer 13

more likely with the HLA-B1502 allele, usually in people with Asian ancestry - screening reccomended