Antiepileptic Drugs

Question 0

Na channel blockers

Answer 0

Phenytoin (Oxcarbazepine-children)

Fosphenytoin (prodrug)

Question 1

3 ways antiepileptic drugs work

Answer 1

Prevent abnormal changes in ion conductance : block Na,K, Ca channels

Decrease excitatory activity: block NMDA and AMPA receptors

Increase inhibitory transmission: increase GABA synthesis or release

Question 2

Phenytoin

Answer 2

Blocks Na channels by binding to inactive gate delaying onset of neuron firing
Extravasation causes tissue injury
Hypotension

*

Question 3

Phenytoin drug interaction

Answer 3

Increases conversion of primidone to phenobarbital

Enhances carbamazepine by inducing CYP3A4

Question 4

Phenytoin side effects

Answer 4

dont use with juvenile myoclonic seizure

*gingival hyperplasia and hirsutism

Question 5

Felbamate

Answer 5

Glutamatergic (excitatory) receptor antagonist

Use only in:
Lennox-Gastaut Syndrome
Pts highly refractory to other drugs

Inhibits NMDA channel
Binds to NR2B and NR1 subunits, delaying recovery of desensitized NMDA channels

Question 6

What can Felbamate cause?

Answer 6

Liver failure

Question 7

Gabapentin

Answer 7

Releases GABA from glial cells

Used for neuropathic pain and seizures, NOT for controlling seizures

Question 8

GABA agonists

Answer 8

Agonizing GABA increases Cl- influx = hyperpolarization

Gabapentin
Tiagabine
Vigabatrin

Question 9

Tiagabine

Answer 9

Inhibits reuptake of GABA by GABA transporter

Controls tonic-clonic seizures for children under 12

Question 10

Vigabatrin

Answer 10

Inhibits metabolism of GABA by GABA transaminase

Tx of infantile spasm and refractory complex partial seizures

Question 11

Myoclonic seizures

Answer 11

Juvenile
Single/multiple jerks in face, neck, and upper
Most originate from brainstem in the CNS

Question 12

Valproic acid

Answer 12

Tx for juvenile myoclonic seizures

Block Na+ channel

Question 13

Adverse effects of Valproic acid

Answer 13

If used during pregnancy causes Spina bifida

If pregnant, give VPA with folate

Question 14

Zonisamide

Answer 14

Na and Ca antagonist
Myoclonic seizures
*causes renal stones

Question 15

Lamotrigine

Answer 15

Na channel blocker

Myoclonic seizures with mild side effects

Question 16

Absence seizure (petit mal)

Answer 16

Brief and abrupt unconsciousness (5-10sec)
Onset 4-12 and continues to adolescence
High voltage bilaterally synchronous spike wave discharge

Question 17

Ethosuximide

Answer 17

Used to tx absence seizure (petit mal)
Blocks T-type Ca+ channels
Binding reduces Ca entry and suppresses spike wave activity

Question 18

Valproate

Answer 18

Tx absence seizures (petit mal) with tonic-clonic attacks

Question 19

Lamotrigine

Answer 19

Na channel blocker used in children with absence seizures

Question 20

Status epilepticus

Answer 20

Seizure activity the lasts 10min without recovery, or two or more seizures within 30min

Mostly in ppl >30

Question 21

Lorazepam

Answer 21

Benzodiazepine
GABA agonist 
Low lipid solubility 
Lasts 6-12hrs
Less respiratory depression

Question 22

Diazepam

Answer 22

Benzodiazepine
GABA agonist

High lipid solubility -accumulates, toxicity
Rapid onset
Respiratory depression and hypotension

Question 23

Partial and generalized seizures tx

Answer 23

Phenytoin, Oxcarbazepine (child)

Question 24

Myoclonic seizures tx

Answer 24

Valproic acid

Question 25

Absence seizures tx

Answer 25

Ethosuximide

Question 26

Status epilepticus tx

Answer 26

Benzodiazepines

Question 27

Infantile spasms tx

Answer 27

Vigabatrin