Antiseizure meds

Question 1

Tonic-clonic seizures

grand mal

Answer 1

• most common type
• generalized alternating muscle spasms and jerkiness

Question 2

Absent seizures

petit mal

Answer 2

• brief loss of consciousness (10s or less)
• most common in children

Question 3

Partial/psychomotor seizures

Answer 3

• repetitive behaviors like chewing or swallowing motions
• behavioral changes
• motor seizures

Question 4

Phenytoin

dilantin

Answer 4

• hydantoin
• contraindicated in pregnancy
• therapeutic serum level –> 10-20mcg/mL
• S/E: gingival hyperplasia, purple glove syndrome, vfib, suicidal ideation, pink urine, blood dyscrasias, SJS, nystagmus, ataxia, miosis
• interacts w/ sulfonamides, antineoplastics, antipsychotics, anticoags, oral contraceptives, corticosteroids
• advise alternative contraceptive methods

Question 5

Phenobarbital

Answer 5

• barbiturate
• enhances GABA activity
• used for tonic-clonic, partial, myoclonic seizures, status epilepticus, ETOH withdrawl, sedation
• therapeutic serum level –> 20-40mcg/mL
• S/E: sedation, tolerance, rebound seizures w/ withdrawl
• give on-time when scheduled, discontinue gradually

Question 6

Ethosuximide

Answer 6

• succinimide
• decreases calcium influx
• used for absent seizures
• therapeutic range –> 40-100mcg/mL
• S/E: blood dyscrasias, renal & liver impairment, systemic lupus erythematosus

Question 7

Benzodiazepines

Answer 7

• clonazepam treats absent, myoclonic seizures; tolerance may occur in 6mo
• clorazepate dipotassium treats partial seizures
• diazepam treats status epilepticus (give 1st, IV), short term-effect (give other drug immediately after)

Question 8

Carbamazepine

Answer 8

• iminostilbene
• used for tonic-clonic, partial seizures, bipolar, trigeminal neuralgia, ETOH withdrawl
• S/E: GI distress, ataxia, anemia, agranulocytosis, SJS
• may interact w/ grapefruit juice

Question 9

Valproic Acid

Answer 9

• valproate
• used for tonic-clonic, absent, mixed seizures, bipolar, migraine prophylaxis
• therapeutic range –> 50-100mcg/mL
• S/E: suicidal ideation, thrombocytopenia, hepatotoxicity
• pregnancy category D

Question 10

Gabapentin

Answer 10

• inhibit postsynaptic responses, block post-tetanic potentiation
• used for partial seizures, restless leg, neuropathy
• S/E: SJS, suicidal ideation
• rebound seizures if abruptly stopped
• pregnancy category C

Question 11

Levetiracetam

Keppra

Answer 11

• for partial, tonic clonic, myoclonic seizures
• preferred over phenytoin d/t pregnancy class & less interactions
• S/E: SJS, psychosis, suicidal ideation
• very few drug interactions –> commonly prescribed
• pregnancy category C

Question 12

Antiseizures drugs & pregnancy

Answer 12

• seizures increase 25% in pregnancy
• must stay on meds to protect mom and baby
• many antiseizure drugs are teratogenic
• tend to inhibit vitamin K –> give in last few days of pregnancy or to infant soon after birth
• increase loss of folate (esp phenytoin) in pregnant pts –> daily folate supplements throughout pregnancy

Question 13

Treatment schedule for status epilepticus

Answer 13

• diazepam
• lorazepam
• phenytoin or levetiracetam IV
• midazolam or propofol for continued seizures (sedation)
• slow IV administration to avoid resp depression