EXAM #3: ANTICONVULSANTS II Flashcards
What two drugs are Hydantoins?
Phenytoin
Fos-phenytoin
What is the difference between Phenytoin and Fos-phenytoin?
Fos-phenytoin is a prodrug that is more soluble, making it available for IV and IM preparations
What is the effect of Phenytoin on metabolism?
Induction of cytochome p450
What type of elimination does Phenytoin undergo?
Zero-order i.e. system can become SATURATED
What is the mechanism of action of Phenytoin?
1) Blocks Na+ channels by binding the voltage gated Na+ channel in the inactivated state
2) Enhances GABA release
3) Decreases glutamate release
4) Prevents seizure propagation
What are the clinical indications for Phenytoin?
1) Grand mal seizure
2) Patrial seizure
3) Status epilepticus
What is the unique adverse effect that is strongly associated with Phenytoin?
Gingival Hyperplasia
What is Fetal Hydantoin Syndrome?
Teratrogenic syndrome including cleft lip and palate cause by Phenytoin ingestion during pregnancy
What class of drug is Carbamazepine?
Tricyclic
What is the mechanism of action of Carbamazepine?
Inhibition of voltage-gated Na+ channels
What is the effect of Carbamazepine on metabolism?
Potent induction of CYP p450
What is Oxacarbazepine?
New drug with similar structure to Carbamazepine that has FEWER side effects
What are the clinical indications for Carbamazepine?
1) General tonic-clonic seizures
2) Partial seizures
3) Trigeminal neuralgia
4) Bipolar disorder (manic phase)
What is the drug of choice for trigeminal neuralgia?
Carbamazepine
What is the unique side effect of Carbamazepine?
SIADH i.e “Syndrome of Inappropriate ADH Secretion” leading to fluid retention and hyponatremia
Also, like Phenytoin, a potent Teratogen