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