030515 antiseizure drugs

Question 1

many of the anti-epileptic drugs are metabolized by

Answer 1

liver (a good percent of the drug is metabolized by liver in many cases)

Question 2

phenytoin MOA

Answer 2

use dependent effect on sodium channels-keep inactivation gate closed longer

Question 3

uses of phenytoin

Answer 3

generalized tonic-clonic seizures

partial seizures

Question 4

the anti-epileptic drugs are highly protein bound-what implciations does this hv?

Answer 4

can interact w other drugs that are protein bound

Question 5

side effects of phenytoin

Answer 5

CNS-dose dependent-nausea, anorexia, apathy, sedation, ataxia, nystagmus, diploplia

dose-independent:

• gingival hyperplasia
• hirsutism
• teratogenicity
• hypersensitivity rxns

Question 6

MOA of carbamazepine

Answer 6

similar to phenytoin

Question 7

use of carbamazepine

Answer 7

partial seizures

Question 8

notable toxicity of carbamazepine

Answer 8

teratogen: increased risk of spinal bifida, though risk is lower than w valproic acid

Question 9

oxycarbazepine

Answer 9

newer analog of carbamazepine. less likely to cause CNS side effects and less enzyme induction

Question 10

use of ethosuximide

Answer 10

first choice drug for absence seizures

Question 11

MOA of ethosuximide

Answer 11

reduces low threshold T-type Ca currents in thalamic neurons

Question 12

MOA of valproic acid

Answer 12

blocks repetitive neuronal firing (good for partial seizure)

may reduce t type Ca currents (good for absence seizures)

increases GABA concen

Question 13

use of valproic acid

Answer 13

absence sizures
absence seizures w concomitant generalized tonic clonic seizures

generalized tonic clonic seizures and partial seizures

myoclonic seizures

Question 14

side effects of valproic acid

Answer 14

teratogenicity-spinal bifida
hepatotoxicity

these are the non- dose related ones

Question 15

felbamate MOA

Answer 15

acts at glycine modulatory/allosteric site on NMDA receptor as antagonist. also potentiates GABA

Question 16

use of felbamate

Answer 16

partial seizures refractory to other agents

Question 17

gabapentin MOA

Answer 17

unknown

Question 18

use of gabapentin

Answer 18

adjunct therapy in tx of partial seizures w or wo secondarily generalized tonic clonic seizures

Question 19

MOA of pregabalin

Answer 19

structurally similar to gabapentin but more potent

Question 20

use of pregabalin

Answer 20

adjunctive therapy for partial seizures

management of neuropathic pain

Question 21

MOA of lamotrigine

Answer 21

blocks repetitive APs and may block Na ch

Question 22

use of lamotrigine

Answer 22

partial, generalized tonic-clonic and absence seizures

not as good as ethosu. and valproic acid for absence seizures

Question 23

MOA of topiramate

Answer 23

inhibits excitatory transmission by antagonizing ability of excitatory amino acids to activate the kainate/AMPA subtype of glutamate receptor

blocks the SPREAD of seizures

Question 24

use of topiramate

Answer 24

add-on therapy for partial seizures

Question 25

tiagabine

Answer 25

inhibits GABA transporter (GAT-1) and thus reuptake of GABA

Question 26

use of tiagabine

Answer 26

add-on tx for both complex and simple partial seizures

Question 27

levetiracetam MOA

Answer 27

unknown

Question 28

use of levetiracetam

Answer 28

adjunct tx for partial seizures | adjunct tx of myoclonic seizures

Question 29

zonisamide MOA

Answer 29

acts at both Na and Ca ch. reduces voltage-dependent transient inward currents (T-type Ca currents)

Question 30

use of zonisamide

Answer 30

adjunct tx of adults w partial seizures

Question 31

vigabatrin MOA

Answer 31

acts by irreversibly inhibiting GABA metabolism-GABA transaminase inhibitor

Question 32

use of vigabatrin

Answer 32

adjunct tx of refractory complex partial seizures and infatile spasms

Question 33

clobazam

Answer 33

adjunct tx for seizures associated w Lennox Gastaut syndrome (severe form of epilepsy) blocks voltage dependent Na and Ca ch, suppresses neuronal hypersynchronization and inhibits carbonic anhydrase

Question 34

lacosamide

Answer 34

enhances slow inactivation of voltage gated Na ch adjunct tx of partial seizures

Question 35

perampanel

Answer 35

new drug AMPA allosteric antagonist partial seizures

Question 36

ezogabine

Answer 36

adjunct tx of partial seizures K ch facilitator (UNIQUE)

Question 37

rufinamide

Answer 37

not clearly known adjunct tx of seizures assoc w Lennox Gastaut syndrome