Anticonvulsants Flashcards
anticonvulsants
Phenytoin (dilantin)- Hydantoins carbamazepine (tegretol) oxcarbazepine (trileptal) valproic acid (depakote) lamotigrine (lamictal)
Phenytoin (dilantin)
indications & pharmacodynamics
indications : tonic clonic and partial complex seizures
pharmacodynamics: inhibit and stabilize electrical discharges in the motor cortex of the brain affecting the influx of sodium ions during generation of nerve impulses
Phenytoin (dilantin)
drug to drug interactions
CYP 450 system.
levels will increase with CIMETIDINE, diazepm, alcohol intake, valproic acid, allopurionol.
levels decrease with barbituates, ANTACIDS, calcium.
CARBAMAZEPINE, ESTROGEN, acetaminophen, corticosteroids, levodopa, sulfonylurea, DIGOXIN.
Phenytoin (dilantin)
caution and contraindications
What form of this med cannot be given in primary care setting and why.
- avoid in sinus bradycardia, 2nd and 3rd degree AV heart block, stocks-adams syndrome,
- hypotension, myocardial insufficiency,
- renal and hepatic impairment
- elderly,
- avoid in pregnancy and lactation
- approved in pediatrics
narrow therapeutic range.
do not give IV and IM in primary care setting d/t cardiac side effects from influx of calcium which leads to influx of potassium.
Phenytoin (dilantin) ADRs..
** s/s are most important
agitation, ataxia, confusion*, Dizziness*, drowsiness, headache, nystagmus, hypotension*, tachycardia*, n/v/ anorexia*, altered taste, gingival hyperplasia*.
Phenytoin (dilantin)
patient education
discolored urine, avoid alcohol
suicidal ideation, risk factors for seizures(decrease caffeine), no driving if not seizure free for 1 year, oral hygiene (rinse mouth, brush teeth), report ADRS, hypersensitivity of fever and skin rash that occurs 3-8 weeks of treatment.
phenyotin (dilantin)
monitoring
suicidal ideation,
blood dyscrasias,
baseline dilantin level. NEVER abruptly stop medication
TSH level due to increased metabolism that can happen from the medication ( ie tachycardia and hypotension from overdriven metabolism).
monitor use of ibuprofen and antacids because these can decrease effect of the phenytoin
carbamazepine ( tegretol)
indicated for focal and generalized onset of seizures
MOA: unclear. thought to affect sodium channels, slowing influx of sodium into cortical neaurons and slowing the spread of abnomal activity
carbamazepine ( tegretol)
BBW
steven johnsons’s syndrome and toxic epidermal necrolysis in chinese patinets
strong association in HLA-B 1202 allele variant in developing these conditions.
blood dyscrasias (lower WBC) bone marrow depression leading to pancytopenia and aplastic anemia
carbamazepine ( tegretol)
monitoring
baseline CBC (for blood count), CMP, TSH prior to initiating, liver enzymes (because it is metabolized and damaged by liver)
carbamazepine ( tegretol) caution and contraindication
renal and hepatic impairment,
avoid in pregnancy and lactation,
caution in elderly (can induce confusion and agitation).
approved in pediatrics.
carbamazepine ( tegretol) ADRs
drowsiness, dizziness, ataxia, nausea, vomiting, skin rash, pruritus, constipation, tremor, rare behavior changes, rare suicidal ideations, multiorgan hypersensitivities, which are rare, and hepatotoxicity, which is rare
narrow therapeutic range: toxicity can present as HTN, tachycardia, stupor, agitation, respiratory depression, nystagmus, urinary retention, seizures, coma.
carbamazepine (tegretol) patient education
report if there’s any new onset of skin lesions, bruising, fever, or sore throat.
avoid grapefruit juice
Lamotigrine
indications and pharmacodynamics
partial seizures, and generalized tonic clonic seizures.
affects voltage sensitive sodium channels and inhibit presynoptic release of glutamate and asparate in the neuron.
Lamotigrine
BBW
serious skin reactions.
rebound status epilepticus with sudden withdrawal
Lamotigrine caution and contraindications
- renal and hepatic impairment,
- avoid in pregnancy and lactation
- ok for children >2 y/o. children are at increased risk for skin reaction
Lamotigrine ADRs
dizziness, headahce, gi upset, diplopia, ataxia, insomnia, skin rash,
and rare- suicidal ideations, blood dycrasias, multiorgan hypersensitivities
Lamotigrine patient education
immediately report new onset rash.
oral interaction with oral contraceptives (decreased level of the lamotrigine)
zonisamide indications and pharmacodynamics
partial seizures in adults
MOA: unknown, thought to block voltage dependednt sodium channel.
zonisamide ADRs
somnolence, anorexia, dizziness, headache, agitation, memory difficulties, aplastic anemia, and agranulocytosis.
can decrease sweating and lead to hyperthermia.
rebound seizure with sudden withdrawal
zonisamide caution and contraindications
hypersensitivity to sulfonamides, avoid with sulfa allergy, renal and hepatic impairment, avoid in pregnancy and lactation approved for peds >16 y/o
Succinimides (thosuximide)
indications and pharmacodynamics
absent seizures
MOA: decrease nerve impulses and transmission in the motor cortex.
Succinimides (thosuximide) ADRs
gi distress, sedation, ataxia, lethargy, headache, pruritus, mood changes, rash,
rare ADRS- suicidal ideation, blood dyscrasias, and skin reactions. Lupus
toxicity s/s: CNS depression, resp depression, n/v
Succinimides (thosuximide)
patient teaching
take with food.
do not take with alcohol
backup birth control (this med reduces effectiveness of birth control).
Succinimides (thosuximide)
caution and contraindications
close monitoring in pregnancy,
avoid in lactation,
rebound seizures with withdrawal, caution in renal and hepatic impairment,
approved in peds >3 y/o
valproic acid
focal, partial onset seizures, gereral onset seizures, focal onset impaired awareness and absence seizures.
MOA: increases GABA availability and enhances the action of GABA and mimics its action in the post synaptic sites.
blocks voltage dependent sodium channels, results in high frequency repetitive neural firing.
valproic acid ADRs
headache, drowsiness, dizziness, nausea, vomiting, tremor, visual disturbances, weight gain, behavioral changes
Rare ADRs- suicidal ideation, brain atrophy
toxic s/s: CNS depression, confusion, jaundice.
valproic acid BBW
hepatotoxicity in severe pancreatitis.
valproic acid caution and contraindications
elderly, avoid in pregnancy and lactation, avoid in children <2 y/o Beers list medication, rebound seizures with withdrawal.
gabapentin indications and pharmacodynamics
focal seizures, neuropathic pain, neuralgia
GABA analogue that binds to unknown receptors in the brain. does not bind to GABA receptors.
mist be titrated up to goal dose
gabapentin patient education
food increases absorption
gabapentin ADRs
Dizziness, drowsiness, fatigue, ataxia, peripheral edema, abnormal thinking, neuropsychiatric events have been reported with 3 to 12-year-olds, suicidal ideation is rare
gabapentin caution and contraindications
benefit outweighs risk in pregnancy and lactation
avoid in children <3 y/o,
caution in renal impairment. OK for the liver.
caution in elderly d/t somnolence,
caution in substance abuse patients,
rebound seizures can occur with withdrawal.
topirimate indications and pharmacodynamics
focal seizures, primary general tonic clonic seizures, migraines.
MOA: unclear, but may block sodium channels or potentiate GABA.
topirimate ADRs
ataxia, paresthesia, dizziness, somnolence, difficulty concentrating, mood changes, weight loss, depression.
hyperthermia due to decreased sweating (oligohydrosis)
rare- suicidal ideation
topirimate caution and contraindications
avoid in pregnancy, lactation benefit outweighhs risk, caution in children < 3 MONTHS old, elderly, renal and hepatic impairment, seizures occur with sudden withdrawal.
levetiractam (keppra) indications and pharmacodynamics
focal onset of seizures,general onset seizures.
adjunct therapy.
MOA: unclear, may inhibit first firing without affecting neuron excitability.
68% renal clearance
levetiractam (keppra) ADR
somnolence, dizziness, nervousness, mood distrubance,
RARE- suicidal ideation, blood dyscrasia, and skin reaction.
levetiractam (keppra) caution and contraindications
caution in pregnancy, avoid in lactatio, avoid in children < 1 month old, caution elderly, caution renal impairment****, rebound seizures can occur with sudden withdrawal
A 23-year-old patient who suffered from tonic-clonic seizures was recently discharged from an acute care hospital. The patient needs continued education regarding the daily administration of phenytoin (Dilantin). Which statement by the APN demonstrates the important education needed when phenytoin (Dilantin) is administered?
avoid alcohol
Topiramate (Topamax) is being prescribed to a school-aged child for partial seizures. As the summer approaches and temperatures rise, the nurse practitioner needs to include which of these in patient education?
stay hydrated and avoid high temperatures
anticonvulsant MOA
delay influx of sodium,
delay influx of calcium,
stimulating influx of chloride (that is associated with neurotransmitter gamma-amniobutyric acid)
carbamazepine drug interactions
increases affect: grapefruit juice, cimetidine, erythromycin,
clarithromycin, verapamil,
decreases effect :betablockers, warfarin, doxycycline, haldol
anticonvulsants: succinimides
theosuximide (zarotin)
methsuximaide (celontin)
theosuximide (zarotin)
methsuximaide (celontin) ADRS
gi, somnolence, fatigue ataxia, agranulocytosis, aplastic anemia, granulocytopenia
lamotigrine (lamictal)
used in concurrent sue with valproic acid and phenytoin for primary tonic clonic seizures
lamotigrine (lamictal) drug interactions
decreased by: barbituates, estrogens, phenytoin
increased by: alcohol, carbamazepine, CNS depressant, valproic acid
lamotigrine (lamictal) ADRs
gi (n/v/c), chest pain, peripheral enema,
somnolence, fatiggue, dizziness, anxiety, insomnia, headache, nystagmus, rash
lamotigrine (lamictal) education
adherance, avoid alcohol, avoid otc drugs, adequate hydration, no driving,
levetiractam (keppra) opatient education
when you start med, pt needs to know about balance issues
withdrawal seizures if drug is d/c abruptly.
