anticonvulsants

Question 1

the main MOA for anticonvulsants

Answer 1

sodium channel blockade
potentiate GABA- inhibitory neurotransmission
____________________________
calcium channel blockade- T-type
decrease glutamate- excitatory neurotransmission

Question 2

seizure tx

Answer 2

initial therapy is usually based on the type of seizure documented
can either block initiation of electrical charge, or prevent the spread of abN electrical discharge to adjacent brain areas

Question 3

drugs for partial seizures

Answer 3

carbamazepine/ tegretol
phenytoin/ dialantin
DIAZEPAM/ VALIUM
PRIMIDONE/ MYSOLINE
valproic acid/ depakote

Question 4

drugs for absence seizures

Answer 4

ETHOSUXIMIDE/ ZARONTIN
valproic acid/ depakote
clonzepam/ klonapin

Question 5

drugs for generalized tonic-clonic seizures

Answer 5

DIAZEPAM/ VALIUM
phenytoin/ dilantin
carbamazepine/ tegretol
PHENOBARBITAL/ PHENOBARB
primidone/ mysoline
LAMOTRIGINE/ LAMACTIL
levetriacetam/ keppra
topiramate/ topamax

Question 6

drugs for status epilepticus

Answer 6

DIAZEPAM/ VALIUM
lorazepam/ ativan** longer half life makes it more commonly used in place of diazepam
PHENOBARBITAL/ PHENOBARB

Question 7

Phenobarbital/ Phenobarb

Answer 7

barbituate anticonvulsant
for generalized siezures
MOA- enhanced GABA activity
IV/PO- slow onset(>30min), VERY LONG HALF LIFE(>50hrs)
may be initial drug of choice for children w/seizures
metabolized by P450 enzymes
SE- CNS depression, drowsiness, LOW IQ in children of chronic tx

Question 8

Primidone/ Mysoline

Answer 8

barbituate anticonvulsant
for all types of seizures EXCEPT abscence seizures
MOA- exact mech unknown- PHENOBARBITAL IS A KNOWN METABOLITE OF PRIMIDONE- GABA inhibition is considered chief MOA
PO, metabolized in liver, plasma 1/2 life 10-12hrs, metabolites 1/2 life >48hrs
SE- nausea, anorexia, HA, vertigo, ataxia
CATEGORY D

Question 9

diazepam/ valium

Answer 9

Long acting benzodiazepine anticonvulsant
for grand mal seizures, STATUS EPILEPTICUS, seldom used as chronic tx of seizures. anxiety, panic DO
MOA- inc. sensitivity of GABA receptors to GABA, inc. CL influx which inhibits CNS

Question 10

clonazepam/ klonapin

Answer 10

Long acting benzodiazepine anticonvulsant
as an alternative to ethosuximide or valproic acid for absence seizures & for status epilepticus, also good for insomnia
MOA- similar to diazepam( inc. sensitivity of GABA receptors to GABA, inc. CL influx which inhibits CNS)
PO- long lasting
SE- drowsiness, altered mentation, additive with CNS depressants, MARKED ABUSE POTENTIAL, developed tolerance

Question 11

Phenytoin/ dilantin

Answer 11

anticonvulsant
for prophylaxis of all types of seizures except abscene
MOA- reduces NA & CA currents across neuronal membranes
PO/IV/IM- slow onset, long half life, tolerence develops
SE- NYSTAGMUS, GINGIVAL HYPERPLASIA, ataxia, possible hepatotoxicity, possible bone marrow supression- IV admin may cause hypotension & arrythmias
monitor blood levels of the drug early on, dose comparativly to SE vs seizures

Question 12

carbamazepine/ tegretol

Answer 12

anticonvulsant
for prophylaxsis of all seizure types except absence. tx CHRONIC PAIN- trigeminal neuralgia & post herpetic neuralgia, schizophrenia & bi-polar DO
MOA- red. NA & CA currents across neuronal membranes
PO, induces CYP450
SE- vertigo, N/V, possible bone marrow suppression & aplastic anemia- follow blood counts
never give to pts on MAOI’s!- hypertensive crisis

Question 13

valproic acid/ depakote

Answer 13

anticonvulsant
for all seizure types- esp. absence & combined types, bi-polar DO, chronic pain
MOA- unknown, postulated enhancement of GABA transmission
PO, IV, metabolized in liver, highly protein bound
SE- nausea, insomnia, anxiety, potential for severe hepatotoxicity, folic acid antagonist(inc birth defect)

Question 14

ethosuximide/ zarontin

Answer 14

anticonvulsant
for absence seizures(1st choice)
MOA- unknown- T-type CA channels?
PO, metabolized in liver not protein bound. inc phenytoin levels, less hepatotoxic
SE- HA, N/V, fatigue, ataxia, blurred vision, confusion, skin rashes, GINGIVAL HYPERPLASIA, LUPUS LIKE SYNDROME

Question 15

gabapentin/ neurontin

Answer 15

anticonvulsant, atypical analgesic
for adjunctive tx of patrial seizures. CHRONIC PAIN, POST HERPETIC NEURALGIA, migraines, withdrawl ssx for meth & cocaine
MOA- potentiates GABA(was designed to look like GABA) & affects N-type CA channels
absorbtion decreased by use of antacids, reduce dose with renal dysf
SE- somnolence, dizziness, ataxia, HA, & other CNS SE
successor drug- pregabalin/ lyrica

Question 16

lamotrigine/ lamactil

Answer 16

anticonvulsant
for tonic-clonic seizures, complex partial seizures, or seizures resistant to other tx’s, mood stabilizer
**1st drug approved for bi-polar since lithium(2003)
MOA- unknown, may stabilize neurons by dec sensitivity to excitatory glutamate & aspartate
PO
SE- dizziness, HA, vertigo, diplopia, somnolence, ataxia

Question 17

levetiracetam/ keppra

Answer 17

anticonvulsant
for tonic clonic, complex partial, or seizures resisant to other tx’s
MOA- unkonwn. inhibition of CA through presynaptic channels
PO
SE- gen well tolerated, drowsiness, weakness, unsteady gait, coordination problems, HA, mood chx, nervousness, anorexia, vomiting, diarrhea or constipation, possible skin pigment chx