Anti-Epileptics & Convulsants (exam 2)

Question 1

Phenytoin (Dilantin)

Answer 1

-used with adults to treat tonic/clonic (and some partial)
-increased half life with increased dose (zero order kinetics)
-decreases discharge speed; increases inactive state, decreasing repetitive firing
TOX: can decrease cognitive fxn, so not used with children
-cannot be used in absence
elderly: peripheral neuropathy
children: gingival hyperplasia
hirsutism
BLOOD DISORDER: SJS, Toxic epidermal necrolysis

Question 2

Carbamazepine (Tegretol)

Answer 2

• TCA derivative; can be used in bipolar disorder
• decreases Na+ into cell, decreasing repetitive firing, enhances adenosine inhibition
• treats tonic/clonic, partial (psychomotor)
• cannot be used in absence
• TOX: ADH inhibition, agranulocytosis, SJS, TEN

Question 3

Phenobarbital

Answer 3

-treats tonic/clonic, and partial seizures
-enhances GABA/inhibit NMDA
-high risk of status epilepticus with rapid withdrawal!
TOX: less risk of blood disorders, but increased risk or rash, paradoxical hyperactivity

Question 4

Ethosuximide (Zarontin)

Answer 4

• treats absence seizures most effectively
• blocks Ca T-type channels
• TOX: GIT problems, rarely causes blood disorders

Question 5

Valproic Acid (Depakane)

Answer 5

-treats absence, but can be used with other agents to treat tonic/clonic
-decreases Na+ influx, blocks Ca++ channels, decrease GABA breakdown increase synthesis
-inhibits metabolism
-TOX: low, but NVD, GIT issue
RARE: fatal hepatitis, birth defects

Question 6

Clonazepam (Klonopin)

Answer 6

• BZD, treats absence and myoclonic seizures
• CNS toxicities, decrease with continued use
• enhance GABA, block calcium T-type channels

Question 7

Felbamate (Felbatol)

Answer 7

-decrease Na+ influx, decrease NMDA transmission
-second line agent
TOX: rare, but aplastic anemia and hepatic failure
-insomnia, nausea, dizziness, ataxia, diplopia

Question 8

Gabapentin (Neurontin)

Answer 8

indirect mechanism, increase GABA, block Ca++ channels
treats neurotrophic pain
low toxicity of fatigue, ataxia, dizzy, visual disturbance

Question 9

Lamotrigine (Lamictal)

Answer 9

• treats tonic/clonic and absence
• decreases pre-synaptic Na+
• Tox less than phenytoin, some patients need higher dose though

Question 10

Diazepam (Valium)

Answer 10

• drug of choice to treat status epilepticus

- enhances GABA activity; treats withdrawal symptoms too