AEDs Flashcards
what is the protocol for weaning people off AEDs?
SLOWLY + if person is on more than one AED, discontinue one at a time
what are the 4 traditional AED prototypes?
- phenytoin
- fosphenytoin
- carbamezepine
- valproic acid
what are the 2 newer agents for AEDs?
- gabapentin
2. pregabalin
compare and contrast traditional AEDs and newer agents
EQUAL job of preventing SE
ACUTE (1st starting drug) side effects are equal
newer agents better tolerated, less drug drug interactions, safer with pregnancy
newer agents MORE EXPENSIVE (“the one con”)
what is the most widely used traditional agent + mainstay of epilepsy tx?
phenytoin (dilantin)
what is the therapeutic index for phenytoin?
KNOW THIS; NCLEX question
10-20 mcg/mL
“PHEN = 10”
VERY narrow
describe what “saturation kinetics” is with phenytoin therapy?
liver easily gets overwhelmed –> doesn’t take much for someone to get toxic
what are the s+s of phenytoin toxicity? (5)
- nystagmus
- sedation
- ataxia
- diplopia
- blurred vision
too much phenytoin = lookin’ like you drunk
(the usual s+s…just amplified!!)
SE of phenytoin (3)
+ which one is worse @ start of therapy, but improves over time?
- drowsiness worse @ start; improves over time
- gingival hyperplasia
- GI
how can we educate pts on prevention/management of gingival hyperplasia with phenytoin therapy?
massage gums, flossing, brushing teeth, regular dental care, folic acid supplements
ORAL HYGIENE
how can we combat the GI upset with AED use?
give with food
what are the rare but serious AE of phenytoin? (2)
RASH:
- toxic epidermal necrolysis
- SJS
PHENY is always getting RASHES
can preggos use phenytoin?
NOOOO - teratogenic
what are the administration parameters for IV phenytoin?
- SLOW
how can we avoid purple glove syndrome in IV phenytoin?
NO subcutaneous or IM
NOT in hand veins (only large)
what is the AED that’s the prodrug? what is it converted to in the body?
prodrug: fosphenytoin
converted to phenytoin
“fosphenytoin is the foster brother to phenytoin, they’re similar but VERY different”
what is the dosing for fosphenytoin?
DIFFERENT than phenytoin - dosed in phenytoin equivalents (PE)!!!!
what are the SE of IV fosphenytoin?
temporary paresthesia + itching in groin
(resolves ~ 10 mins after dose)
“the foster brother has crabs, but they get better in 10 mins”
what CV SE can we see with fosphenytoin if given too quickly via IV?
severe hypotension + arrhythmias
what are the SE of carbamezepine?
the usual
CNS (HA, ataxia, nystagmus, blurred vision, sedation)
what are the rare AE of carbamezepine? + based on this, what should we educate patients to report?
- bone marrow suppression
=leukopenia, anemia, thrombocytopenia
- report sore throat, fever, bruising*
2. life threatening rashes: SJS + TEN
what genetic screening should certain patient populations undergo for carbamezepine therapy? why?
asian patients for HLA-B*1502
for increased risk of toxic epidermal necrolysis + SJS
what are the severe AEs of carbamezepine
rash (TEN + SJS) + blood dyscrasisas
what is the unique characteristic of carbamezepine re: half life?
this drug increases its own metabolism –> decreased half life over time
what drug food interactions occur with carbamezepine?
grapefruit
+ LOTS of drug-drug interaxns
what is most common SE of valproic acid?
GI upset
“acid burns the stomach!!”
what are the (3) rare but serious AE of valproic acid?
- hepatotoxicity
- pancreatitis
- blood dyscrasias (leukopenia, anemia + thrombocytopenia)
which AED is the MOST teratogenic?
valproic acid
“you shouldn’t give acid to babies”
what is important teaching point for valproic acid (PO admin)?
don’t crush or chew tablets - swallow whole
can open + sprinkle capsules if if difficulty swallowing
what is dosing like for gabapentin therapy for seizure tx?
HIGHER doses
what are SE of gabapentin? what’s unique about them?
(CNS)
sedation, somnolence, dizziness, ataxia, fatigue, nystagmus
*especially pronounced when starting drug, like traditional AEDs, but IMPROVE OVER TIME ◡̈ *
what are the SE of pregabalin?
2 are unique and different
(CNS)
sedation, dizziness, somnolence, blurred vision, WEIGHT GAIN + EUPHORIA
pregabalin (Lyrica) is what schedule drug?
schedule 5 (due to euphoria)
if someone is in active seizure, what drug therapy would you expect to give?
BENZOS (“calming down GABA”)
ex: lorazepam, diazepam, midazolam
what is IV admin rate for lorazepam?
2mg/min
“LOrazepam = LO + SLO”
what is IV admin rate for diazepam?
5mg/min
“DI = FIve”
which SE of AEDs is common when starting, but generally improves over time?
Sedation
AEDs shouldn’t be taken with what other drug classes + why?
other CNS depressants (ETOH, opioids, antidepressants)
= SAFETY RISK
what should be considered with pregnancy and AED therapy?
risk ratio - is it more harmful for person carrying fetus to have seizure? or is drug more harmful to fetus?
what’s important teaching point to patients on AEDs re: oral contraceptives?
AEDs decrease the effectiveness of OCPs!!!
