Anti-epileptic Drugs

Question 1

What are narrow spectrum agents used for?

Answer 1

Used for partial epilepsy, has some effect against tonic-clonic. Should NOT be used for absence or myoclonus (will worsten).

Question 2

What are broad spectrum drugs used for?

Answer 2

Effective in partial seizures, also effective in generalized seizures

Question 3

Narrow Spectrum Drugs

Answer 3

Carbamazapine
Phenytoin
Phenobaribital
Gabapentin
Tiagabine
(CAR PHENders and PHlatBeds Go Past Tags)

Question 4

Broad Spectrum Drugs

Answer 4

Lamotrigine
Clonazepam
Topiramate
Valproate

(Late and CLoudy on TOP of Vail)

Question 5

Ethosuxamide

Answer 5

Absence epilepsy

Question 6

Lorazepam

Answer 6

Status Epilepticus (IV)

Question 7

Why do seizures spread?

Answer 7

Because they occur next to neurons that think the environment is depolarizing too.

Question 8

Genetic causes of epilepsy

Answer 8

Channelopathies, mutant channels fail to deactivate.

Question 9

AEDs that inhibit sodium channels

Answer 9

Carbamazapine, phenytoin, topiramate, valproate, lamotrigine. Stabilize the inactivated state of the channel, Inhibit burst firing preferentially.

Question 10

AEDs that are GABAa agonists.

Answer 10

Clonazepam, lorazepam, phenobarbital, topiramate

Question 11

AEDs that are GABA reuptake inhibitors

Answer 11

Tiagabine, Gabapentin

Question 12

What type of cellular pathology causes absence epilepsy?

Answer 12

T-type Ca2+ channels cause burst firing in thalamocortical neurons. Intense bursts, lead to absence seizures

Question 13

How does ethosuximide work?

Answer 13

Inhibits T-type Ca2+ channels. Valproate also.

Question 14

Lamotrigine

Answer 14

Na channel inactivator, but also block Ca2+ channels

Question 15

How does topiramate work?

Answer 15

Inactivates Na channels, but also modulates AMPA

Question 16

How to treat status epilepticus

Answer 16

IV Lorazepam/diazepam.

Fosphenytoin IV to prevent recurrence.

Question 17

What if benzos or phenytoin don’t work for status epilepticus

Answer 17

Give phenobarb or valproate.

Question 18

AEDs that induce CYP450

Answer 18

Carbamazepine, phenytoin, phenobarbital

Question 19

Carbamazepine + Phenytoin

Answer 19

Decreased carbamazepine levels (due to induction of CYP)

Question 20

Valproate + Phenobarbital

Answer 20

Increased Phenobarb (metabolism inhibited)

Question 21

Valproate + lamotrigine

Answer 21

Competition for same phase II enzyme. Lamotrigine increased. SJS!!!

Question 22

Valproate + clonazepam

Answer 22

May cause absence status epilepticus, nobody knows how.

Question 23

Stevens-Johnson Syndrome

Answer 23

Caused by co-administration of Valproate + Lamotrigine

Question 24

Terratogenicity

Answer 24

Phenytoin, carbamazepine, phenobarbital, valproate.

Question 25

Suicidal thoughts and AEDs

Answer 25

Yeah they happen sometimes :(

Question 26

Phenytoin PK

Answer 26

Non-linear pharmacokinetics in therapeutic window, which is very narrow. It is slightly less than first order, which means that clearance is constant with changes in concentration, and small increases in doses lead to large fluctuation in concentration.

Question 27

Adverse effects of phenytoin

Answer 27

Gingival hyperplasia

Question 28

Gabapentin FEU?

Answer 28

100%