pharmacology: anticonvulsants Flashcards
phenytoin mechanism and clinical use
blocks axonal Na+ channels in their inactivated states preventing seizure propagation
clinical: everything but absence seizure
phenytoin pharmacokinetics
nonlinear kinetics (reach toxic doses quicker)
induction of cytochrome P450
zero-order kinetic of elimination
phenytoin side effects
- CNS depression
- osteomalacia (decreased vit D = hypocalcemia)
- megaloblastic anemia (decreased folate)
- aplastic anemia (hypersensitivity reaction)
- GINGIVAL HYPERPLASIA!
- HIRSUTISM!
- teratogenicity (cleft lip and palate)
carbamazepine mechanism and clinical uses
blocks axonal Na+ channels in their inactivated states preventing seizure propagation
clinical: everything but absence seizure, DOC for trigeminal neuralgia*****, bipolar disorder
pharmacokinetics carbamazepine
induces cytochrome P450 (including its own metabolism)
carbamazepine side effects
- CNS depression
- osteomalacia
- megalobalstic anemia
- aplastic anemia
- EXFOLIATIVE DERMATITIS
- INCREASED ADH SECRETION
- teratogenicity (cleft lip and palate and spina bifida)
valproic acid mechanism
- blocks axonal Na+ channels in their inactivated states preventing seizure propagation
- inhibition of GABA transminase (increased GABA = CNS depression)
- blockade of T-type Ca channels
valproic acid uses
all seizure states including absence!
mania of bipolar disorders
migraine prophylaxis
valproic acid pharmacokinetics
INHIBITS cytochrome p450
valproic acid side effects
- hepatotoxicity
- thrombocytopenia
- pancreatitis
- alopecia
- teratogenecity (spina bifida)
ethosuximide mechanism
blockade of T-type ca channels in thalamic neurons
what is the DOC for absence seizures?
ethosuximide
which drug is the best choice when taking oral contraceptives?
valproic acid
what are the drugs used for anticonvulsants?
carbamazepine, phenytoin, ethosuximide, valproic acid, diazepam, lorazepam
