Chapter 21: Drugs for Seizure Disorders Flashcards
2 type of seizure
focal
generalized
main goal of terapuetic intervention
- Lower neuronal excitability AND/OR
- Enhance neurohormonal inhibition
antisz drugs thst block Na channels
a. Carbamazepine (Tegretol)
b. Oxcarbazepine (Trileptal)
c. Lamotrigine (Lamictal)
d. Phenytoin (Dilantin)
e. Topiramate (Topamax)
f. Valproic Acid (Depakene)
g. Zonisamide (Zonegran)
antisz drugs tht block Ca channels
(many act on multiple targets)
a. Lamotrigine
b. Topiramate
c. Valproic Acid
d. Zonisamide
e. Gabapentin(Neurontin)
f. Pregabalin(Lyrica)
g. Levetiracetam (Keppra)
antisz drugs: block NMDA receptor
a. Felbamate (Felbatol)
antisz drugs: GABA potentiation
a. Benzodiazepines (i.e. diazepam)
b. Barbiturates (i.e. phenobarbital)
c. Tiagabine (Gabitril)
d. Vigabatrin (Sabril)
e. Valproic Acid
antisz drugs SE
- Hyponatremia
- Visual problems
- Gingival hyperplasia
- Cognitive problems
- CNS depression
- Weight gain or weight loss
- Peripheral edema
- Liver Toxicity
- Aplastic Anemia
anti sz drugs prescribing concerns
• Goal: To minimize or eliminate seizure events
• Baseline Data: Pregnancy test. For all antiseizure drugs, assess seizure frequency and type. Conduct a depression screening.
• Lab: CBC, liver function, renal function, (serum sodium for NA blockers)
• Pregnancy Concerns: Risk Vs Benefit ratio. So, women with major seizure disorders should continue on their antiseizure medications. Use lowest effective dose with only one drug if possible.
• Valproic Acid is HIGHLY teratogenic
• Abrupt withdrawal of antiseizure mediations can lead to status epilepticus. With draw slowly (over 6 weeks). FU visits to assure patient has enough medication.
• Monitor CNS depression (common at first with all of these drugs). Avoid driving until patient acclimates to the dose.
phenytoin (dilatin)
• Most widely used antiseizure drug despite having troublesome side effects. Useful against partial and complete seizures.
• MOA: Inhibition of Na Channels
• Use: ALL types of seizures except absence seizures. Especially effective against tonic-clonic seizures in adults. (Carbamazepine is preferred for treating tonic clonic seizures in children).
• Dosage: Dosing is highly individualized Plasma drug levels are often monitored as an aid to establishing dosing.
• Goal: Levels between 10 and 20 mcg/mL (> 20 + toxicity, < 10 seizures are not controlled)
• SE: CNS effects especially with large doses. Gingival hyperplasia (seen in 20% of pts taking phenytoin) Teach proper mouth care. Teratogen in pregnancy. When administered IV, cardiac dysrhythmias and hypotension may result. Inject slowly
valporic acid (depakene)
• Used widely to treat all major seizure types and epilepsy. Also used for Bipolar and migraine HA prophylaxis
• MOA: GABA
• Use: Considered first line drug for all partial and generalized seizures.
• SE: Generally, well tolerated. Sedation, GI effects
Phenobarbital
class: barbiturate
• One of the oldest antiseizure drugs, effective and inexpensive and administered just once daily. Serious CNS side effects occur so this is not used first line.
• It is a preferred barbiturate BC it can suppress seizures while only causing moderate disruption of CNS function. BC of this, it is classified as an “anticonvulsant barbiturate” to distinguish it from most other barbiturates which are employed primarily as sedatives.
• Schedule IV Drug of the Controlled Substances Act* (May cause dependence but with the epilepsy doses, dependence is unlikely).
• MOA: Potentiates effects of GABA
• Use: Partial and generalized but not absence seizures
• Dosage: Very long half-life, so once daily dosing. Loading doses are needed to increase serum levels at first.
• SE: Drowsiness. With use, tolerance to sedation develops. Depression may occur. Respiratory depression is a side effect (Use cautiously in patients with respiratory problems)
• Reduce gradually to prevent withdrawal.
