Antiepileptic Drugs

Front 1

Carbamazepine

Back 1

Mech: -Na channel block
-blocks catecholamine reuptake
- clonidine (alpha2 agonist) blocks anticonvulsant effects
use: all but absence seizures; trigeminal neuralgia, bipolar dep, neuropathic pain
toxicity: water retention / intoxication (inc. ADH)
side fx: less toxic; less sedative
notes: stimulates own metabolism, longer take, shorter 1/2 life

Front 2

Phenytoin

Back 2

Mech: Na channel block
use: tonic clonic, partial, and psychomotor
toxicity: severe skin, bone marrow, liver, gingival, hyperplasia, folic acid deficiency, Ca absorption
side fx:
notes: Dose dependent elimination; dont give to pregnant women

Front 3

Phenobarbitol

Back 3

Mech: enhance GABA effect by keeping GABA receptor open longer
- also blocks Ca channels (not T-type)
use: tonic-clonic, simple partial, complex partial
toxicity:
side fx: convulsions possible w/ withdrawal
notes: pH dependent excretion so make urine more alkaline to increase secretion; long 1/2 life - 4 days

Front 4

Valproic Acid

Back 4

Mech: Na and Ca (t-type) channel block inhibits GABA breakdown
use: absence, myoclonic, atonic, partial/secondary generalization
toxicity: idiosyncratic hepatotoxicity
side fx:
notes:

Front 5

Ethosuximide

Back 5

Mech:blocks t-type Ca channel
use: absence only
toxicity: aplastic anemia
side fx: LOW B/C DONT USE CYP450
notes:

Front 6

Diazepam (and other BZ's)

Back 6

Mech: allosteric modulator of GABA-A causing more frequent Cl- channel opening and hyperpolarization of cell
use:status epilepticus
toxicity:
side fx:tolerance, highly sedative, ataxia
notes: Lorazepam - longer duration for status epil.
Clonazepam - oral - for absence
Chlorazepate - complex partial

Front 7

Lamotrigine

Back 7

Mech: NA channel block
- also anti-folate activity
use: partial w/ secondary generalization
toxicity:
side fx:
notes: Group I

Front 8

Felbamate

Back 8

Mech: Na channel block
NMDA block
enhances GABA
use: partial
toxicity: aplastic anemia
side fx:
notes: Group I
- back on market now but must monitor carefully

Front 9

Topiramate

Back 9

Mech: Na channel block
inhibits AMPA
enhances GABA
use: intractable partial seizures and 2ndary agent for partial seizures
toxicity:
side fx: weight loss
notes: Group I
-weak carbonic anhydrase inhibitor

Front 10

Vigabatrin

Back 10

Mech: inhibits GABA-T
use: partial seizures
toxicity: sedation, agitation, weight gain, psychosis
side fx:
notes: Group II

Front 11

Tiagabine

Back 11

Mech: inhibits GABA-T
use: adjunctive partial seizures
toxicity: abnormal thinking - mental lethargy or difficulty concentrating
side fx:
notes: Group II

Front 12

Gabapentin

Back 12

Mech: controversial:
-binds to GABA B heterodimer linked to K and N-type VGCC
Ca channel: overexpressed in nerve injury; N, L, P/Q-type VGCC
-may interact at presynaptic NMDARs ( /)
-non-vesicular GABA
use: partial
toxicity:
side fx:
notes: Group II
NOT METABOLIZED by CYP450, NO INTERACTIONS

Front 13

Levetiracetam

Back 13

mech: selective blockade of n-type Ca channels
- reduction of voltage operated K current
- does not modulate neuronal Na and T-type Ca2+ currents
Use: refractory partial seizures
notes: Group II
NOT METABOLIZED BY CYP450, little side fx