- Conventional Medications

- 2nd most common prescribed anticonvulsant (partial)

- MoA: inhibits voltage-gated Na+ channels

- cytochrome p450, 90% bound to protein (albumin), 24 hr 1/2-life, 5 days to steady state

- disproportionate rise w/ small increase in dose

- IV rapid load (fosphenytoin)

- Acute SE: cerebellar/vestibular, drowsiness, arrhythmias, hypotension

- Chronic SE: Gingival growth, hirsutism, PN, osteomalacia

Phenytoin (Dilantin)

- Conventional Medication

- most prescribed anticonvulsant (partial)

- MoA: inhibit voltage-gated Na+ channels

 - 70% protein bound, p450 to 10,11-epoxy which has anti-epileptic properties

- SE: drowsiness, vertigo, diplopia, aplastic anemia, SIADH w/ hyponatremia

- Tx for Trigemincal neuralgia

Carbamazepine (Tegretol)

- Conventional Medication (partial seizures)

- MoA: increases GABA-A receptor (increased duration)

- p450, 1/2-life 96 hr, 3 weeks to steady state, 1x/day, IV for status epilepticus

- less effective than phenytoin/carbamazepine

- SE: sedation/slowed mentation, children the opposite, ataxia/nystagmus

Phenobarbital

- conventional medication

- metabolized to phenobarbital and PEMA

- used for essential tremor

Primidone (mysoline)

- Conventional medication (partial/generalized seizures)

- MoA: prolonged voltage-gated Na+ channels, reduces low-threshold Ca++ channels, results in elevated GABA (inhibits degradation)

- highly protein bound and displaces phenytoin --> toxicity w/o elevated bound phenytoin levels, 95% liver metabolism, 1/2-life 15 hr, IV available

- used for manic-depressive, migraines

- SE: GI, sedation, tremor, weight gain, fatal fulminate hepatitis (elevated liver enzymes), acute pancreatitis/hyperammonemia

Valproic acid (Depakote)

- Conventional Medications (status epilepticus)

- MoA: enhances GABA synaptic inhibition

- very short 1/2-life, calms anxiety, abruptly stopping --> withdrawl seizures, steady state in 1-4 hrs

- SE: sedation, death due to respiratory failure

Loraxepam (ativan) & diazepam (valium)

Benzodiazepines

- Newer Anticonvulsants (partial & generalized)

- MoA: inhibit voltage-gated Na+ channels, inhibit glutamate release

- metabolized by glucuronidation (VPA interaction), needs low dose start

- DoC for pregnancy

- 4 weeks to steady state

- SE: rash is rare but serious

Lamotrigine (Lamictal)

- newer anticonvulsant (partial & generalized)

- MoA: complex, inhibits burst firing and hypersynchronization of epileptiform activity

- p450 NOT involved

- IV form available, quick steady state

- SE: irritability and behavioral complaints, somnolence, dizziness, headache

Levitiracetam (Keppra)

- newer anticonvulsants (partial & generalized)

- MoA: inhibits voltage-gated Na+, enhances GABA, limits glutamate receptor (AMPA-kainate subtype)

- estradiol reduced --> higher doses of birth control needed

- SE: numbness and tingling, confusion, "dull thinking", weight loss, kidney stones

Topiramate (Topamax)

- newer anticonvulsants (PN pain and partial)

- MoA: GABA release promoters

- not metabolized, excreted unchanged, does not affect other meds

- SE: sedation, dizziness, fatigue, weight gain

- Tx for pain/paresthesias w/ PN

Gabapentin (Neurontin)