Epilepsy

Question 1

Definition of epilepsy

Answer 1

Group of disorders characterized by excessive excitability of neurons in the CNS

Question 2

Seizures are initiated by synchronous, high-frequency discharge from a group of hyperexcitable neurons called a ______

Answer 2

focus

Question 3

seizures that involve only one side of the brain, person is still conscious

Answer 3

focal seizures

Question 4

seizures that occur when both sides of the brain are involved

Answer 4

generalized seizures

Question 5

formerly called grand mal seizures, these seizures involve total loss of consciousness, contraction/relaxation of muscle groups, periods of hypoxia

Answer 5

tonic-clonic

Question 6

mechanisms of action for antileptic drugs

Answer 6

suppression of sodium and calcium influx
antagonism of glutamate
potentiation of GABA

Question 7

what makes it difficult to find an effective drug and correct dose for epilepsy?

Answer 7

-long seizure free intervals are common, so it can be hard to know if drug is working
-there is a lot of individual variability in response to the drugs as well

Question 8

why is it important to monitor plasma drug levels for antiepileptics?

Answer 8

-narrow therapeutic index
-high interpatient variability in dosing

Question 9

Phenytoin (Dilantin)

Mechanism of Action

Answer 9

Traditional AED
Mechanism: selective inhibition of sodium channels

Question 10

Phenytoin

Half-life
Therapeutic range

Answer 10

Varied oral absorption
Half-life 8 to 60 hours
Very narrow therapeutic range

Question 11

Phenytoin

Adverse effects

Answer 11

-CNS: nystagmus, sedation, cognitive impairment
-Skin & Gums: Gingival hyperplasia, rash (emergency)
-Cardio: hypotension and dysrhythmias a serious risk if given IV
-Birth defects

Question 12

Phenytoin

Interactions

Answer 12

-Decreases the effects of oral contraceptives, warfarin, and glucocorticoids
-Potentiates effects of diazepam, alcohol, and other CNS depressants

Question 13

Carbamazepine (Tegretol)

Adverse effects

Answer 13

-Neurologic effects
-Hematologic effects - leukopenia, anemia, thrombocytopenia
-Birth defects
-Dermatologic effects: rash, photosensitivity reactions

Question 14

Carbamazepine (Tegretol)

Drug interactions

Answer 14

-Decreases level of warfarin and oral contraceptives

Question 15

Valproic acid (Depakote/Depakene/Depacon)

Adverse effects

Answer 15

GI effects
Hepatoxicity (rare)
Pancreatitis
Birth defects (this is the AED associated with the greatest risk for birth defects)

Question 16

What are the traditional AEDs?

Answer 16

Phenytoin, Carbamazepine (Tegretol), Valproic Acid (Depakote)

Question 17

Newer AEDs - safer in pregnancy - fewer drug interactions

Answer 17

Gabapentin
Levetiracetam (Keppra)
Oxcarbazepine (Trileptal)

Question 18

Status Epilepticus

Answer 18

Continuous series of tonic-clonic seizures lasting 20-30 mins