Antiepileptic Drugs Flashcards
What are the 4 Na+ channel stabilizers used for epilepsy? Which ones are used for primary generalized? complex partial?
Phenytoin (Dilantin) [acute seizures, primary generalized]
Carbamazepine [complex partial]
Oxcarbamazepine [complex partial]
Lamotrigine [primary generalized
Besides epilepsy, what are 2 other uses of carbamazepine and other in its class?
Stabilize inactive conformation of Na channel–>
bipolar disorder and neuropathic pain
What are 2 side effects of Lamotrigine and the others in its class?
rash (15%); contraceptive failure due to enzyme induction
What are 2 side effects specific to carbamazepine and oxcarbamazepine? What is the difference between the 2 drugs?
- mild myelosuppression, mild increase in LFTs
- oxcarbamazepine Designed to bypass carbamazepine epoxide; less protein-bound, less autoinduction, fewer interactions, less toxic, longer half-life than carbamazepine
Which Na+ channel blocker is a hepatic enzyme inducer (both auto- and hetero-inducer); highly protein bound; must increase dose in 1-2 wks due to autoinduction?
Carbamazepine
Which Na+ channel blocker competes with Valproic acid for excretion?
Lamotrigine
What are the toxicity side effects of Phenytoin and the others in its class?
Na+ channel blocker–>
“dizzy, drunk, double vision”
Which epileptic agent is teratogenic?
Valproate
What are 4 uses of Valproate?
- seizures (primary generalized & partial)
- bipolar
- migraine prophylaxis
- IV infusion for status epilepticus
What are some side effects of Valproate?
Weight gain, hair turnover, hyperammonemia (which can be mitigated with oral carnitine), teratogenicity, blood dyscrasias; pancreatitis
What are benzodiazepines role in epilepsy?
Status epilepticus (refractory); anesthesia
SE: sedation
Long-term usefulness limited by tolerance
What is the class, mechanism and use of Gabapentin?
GABA analog–>
Block presynaptic influx of Ca++ –>
Adjunct for partial complex epilepsy; more commonly used for neuropathic pain
Which agent is not metabolized in humans? (eat and pee unchanged)?
Gabapentin
What is a voltage-gated Ca++ channel blocker used to treat absense seizures? Side effects?
Ethosuximide–>
Side effects: Nausea (transient), sedation, irritability
What are 2 glutamate receptor blockers? Which receptors do they work at? Used to treat?
Topiramate (AMPA)
Felbamate (NMDA)
treat partial onset seizures [topiramate also headaches]
What are some side effects of Topiramate?
[Ca++ channel blocker]
Toxicity: sedation, “word finding”
SE: mild metabolic acidosis –> tingling, distaste for carbonated beverages, kidney stones, rare acute glaucoma
What is an uncommon but serious side effect of Felbamate?
Uncommon but potentially fatal. Aplastic anemia, acute hepatic failure. Requires monitoring. (not used much anymore)
