Exam 1 - Antiepileptics Flashcards
What are the three partial/focal seizures and which is associated with impairment of consciousness?
simple partial (without), complex partial (with) and secondary generalized
Explain pathophysiology of seizures?
abnormalities in ion channel, increased ENT activity, rhythmic and repetitive hypersynchronous discharge of neurons, seizure focus
What seizures is phenytoin used for? (2)
partial and generalized tonic-clonic
Explain phenytoin pharmacokinetics? (6)
80-90% protein bound, inducer, t1/2 = 20 hrs, TPI = 10-20 ug/mL, 200-400 mg/day, excreted in urine
What is the MOA for phenytoin?
membrane stabilization by blocking Na and Ca influx
What are adverse effects of phenytoin?
gingival hyperplasia, hirsutism, osteomalacia, Hydantoin syndrome
What drug has a similar MOA and clinical uses (+mania and trigeminal neuralgia) as phenytoin?
carbamazepine
Explain carbamazepine pharmacokinetics? (6)
80% protein bound, strong inducing agent, t1/2 = 30 hrs, TPI = 6-12 mg/mL, 200-800 mg/day, excreted in urine
What are adverse effects of carbamazepine?
congenital malformation, hyponatremia and water intoxication, blood dyscrasias (fetal aplastic anemia)
Explain valproate pharmacokinetics? (2)
t1/2 = 15 hrs, excreted in urine
What seizures is sodium valproate used for? (2)
absence, myoclonic
What are adverse effects of sodium valproate?
increased appetite and weight gain, hepatotoxicity, neural tube defects
What is the MOA for levetiracetam?
non-competitive AMPA receptor antagonist
What seizures is levetiracetam used for?
all
What is the dosing for immediate release levetiracetam?
500 mg bid