Drugs for Epilepsy & Seizure

Question 1

MOA of Carbamazepine

*Inducer of CYP450

Answer 1

Converted to carbamazepine epoxide and blocks voltage-sensitive sodium channels

Question 2

Indications of Carbamazepine

Answer 2

Partial and Grand Mal Seizures

Trigeminal neuralgia - condition that can cause chronic intense pain on one or both sides of the face

Alternative to lithium in the treatment of bipolar disorder

Question 3

Adverse effects of Carbamazepine

Answer 3

Ataxia - without coordination, may lead to a lack of balance, coordination, and trouble walking

Diplopia - double vision, causes people to see two of the same image

Pregnancy Category C (Neuronal tube defects)

Question 4

MOA of Phenytoin (Diphenylhydantoin)

*Inducer of CYP450

Answer 4

Blocks voltage-sensitive sodium channels

Question 5

Pharmacokinetics of Phenytoin

Answer 5

Undergoes zero-order kinetics @ high doses

Therapeutic Drug Monitoring
Earliest sign of toxicity - Nystagmus

Question 6

Adverse effects of Diphenylhydantoin

Answer 6

Use of this drug in children is generally avoided

Folate antagonism leading to megaloblastic anemia

Ataxia, diplopia, nystagmus, and slurred speech

Interferes with Vit D metabolism

Gingival Hyperplasia

Hirsutism

Stevens-Johnson syndrome

Toxic epidermal necrolysis

Pregnancy Category D (fetal hydantoin syndrome)

Question 7

MOA of Valproate

*Inhibitor of CYP2C9

Answer 7

Blocks voltage-sensitive sodium channels

Blocks T-type calcium channels

Increases GABA synthesis

Deceases GABA degradation

Decreases glutamate synthesis

Question 8

Indications of Valproate

Answer 8

Broadest antiepileptic spectrum activity (Partial and all forms of generalized seizures)

Rapid Cycling Bipolar disorder

Prophylaxis of Migraine

Question 9

Adverse effects of Valproate

Answer 9

Nausea, GI complaints, weight gain

Mild hepatic toxicity (reversible) - needs monitoring

Pregnancy Category D (neural tube defects)

Question 10

MOA of Phenobarbital and Primidone

Answer 10

Blocks voltage-sensitive sodium channels

Question 11

Adjunct drugs for Partial Seizures

Answer 11

Lamotrigine
Gabapentin
Pregabalin
Topiramate
Tiagabine
Zonisamide
Lacosamide
Levetiracetam
Vigabatrin
Ezogabine
Clorazepate

Question 12

Drugs for Partial and Grand Mal seizures

Answer 12

Carbamazepine
Phenytoin
Valproate
Phenobarbital
Primidone

Question 13

Drugs for Absence, Atonic, & Myoclonic

Answer 13

Ethosuximide
Valproate

Question 14

Drugs for Status Epilepticus

Answer 14

Diazepam
Lorazepam

Notes:
Either drug is administered as a slow
intravenous injection given every 10 to 15
minutes until seizures are controlled or a
maximal dose has been administered.

After diazepam or lorazepam has been
administered, phenytoin is often administered IV
to provide a longer duration of seizure control.
Phenobarbital is used as an alternative.