Pharmacology of Epilepsy

Question 1

Benzodiazepines: MOA

Answer 1

Increases GABA-A action

Question 2

Benzodiazepines: side-effects

Answer 2

Sedation, tolerance, dependence and respiratory depression

Question 3

Carbamazepine: MOA

Answer 3

Blockage of Na+ channels

Question 4

Carbamazepine: side-effects

Answer 4

Diploplia, ataxia, agranulocytosis/anemia, teratogenesis, SIADH, SJS
*CYP-450 induction

Question 5

Ethosuxamide: MOA

Answer 5

Bockage of thalamic T-type Ca++ channels

Question 6

Ethosuxamide: side-effects

Answer 6

EFGHIJ

“Ethosuzamide causes Fatigue, GI distress, HA, Itching and SJS”

Question 7

Gabapentin: side-effects

Answer 7

Sedation, ataxia

Question 8

Lamotrigine: MOA

Answer 8

Blockage of votlage-gated Na+ channels

Question 9

Levetiracetam: MOA

Answer 9

SV2A blocker (inhibition of glutamate release)

Question 10

Phenobarbital: MOA

Answer 10

Increase GABA-A action

Question 11

Phenobarbital: side-effects

Answer 11

Sedation, osteoporosis, respiratory depression, CYP-450 induction

Question 12

Phenytoin: MOA

Answer 12

Blockage of Na+ channels (0-order kinetics)

Question 13

Penytoin: side-effects

Answer 13

PHENYTOIN
P-450 induction
Hirsutism
Enlarged gums
Nystagmus
Yellow-brown skin
Teratogenicity
Osteopenia*
Inhibition of folate absorption
Neuropathy

Question 14

Vigabatrin: MOA

Answer 14

Irreversible GABA-T inhibitor

Question 15

Vigabatrin: side-effects

Answer 15

Complete vision loss

Question 16

Which 2 drugs inhibit conjugation of other drugs by glucuronosyltransferases (UGT) causing accumulation of parent drug?

Answer 16

Valproic acid + Lamotrigine

Question 17

Chronic usage of which 4 drugs are associated with osteopenia/osteoporosis?

Answer 17

Carbamazepine
Phenytoin
Phenobarbital
Valproic acid

-> induce vitamin D catabolism

Question 18

Which 3 drugs are known CYP-450 inducers?

Answer 18

Carbamazepine
Phenytoin
Phenobarbital

Question 19

What are the 3 consequences associated with CYP-450 inhibition in a patient on AEDs?

Answer 19

1. OCP: increased clearance of OCPs; 2-4x increased risk for unplanned pregnancy.
2. Anticoagulants: increased clearance of Warfarin; poor anticoagulations, leading to risk of thrombus/embolus.
3. Antivirals: increased clearance of HIV meds; elevated risk for HIV replication.

Question 20

Which drug is commonly used for partial seizures?

Answer 20

Carbamazepine*

Question 21

Which drug is commonly used for absence seizures?

Answer 21

Ethosuximide

Question 22

Which drugs are used for status epilepticus? (2)

Answer 22

Benzodiazepines (acute)

Phenytoin (chronic)

Question 23

MOA: blockage of VG-Ca++ channels via ad1 (2)

Answer 23

Pregabalin - via ad1

Gabapentin - via ad1

Question 24

MOA: blockage of VG T-type Ca++ channels (3)

Answer 24

Zonisamide
Ethosuxamide
Valproic acid

Question 25

MOA: inhibition of glutamate release/SVA2 blocker (1)

Answer 25

Levetiracetam

Question 26

MOA: irreversible inhibition of GABA-T (2)

Answer 26

Vigabatrin

Valproic acid

Question 27

MOA: NMDA receptor blocker

Answer 27

Felbamate

Question 28

MOA: K+ channel blocker

Answer 28

Ezogabine

Question 29

Valproic acid 3 MOAs

Answer 29

Blockage of VG T-type Ca++
Inhibition of GABA-T
Blockage of VG Na+ channels

Question 30

Topiramate 3 MOAs

Answer 30

Blockage of VG Na+ channels
AMPA blocker
Post-synaptic GABA agonist