Blocks sustained high-frequency repetitive firing of action potentials by binding to and prolonging the inactivated state of the Na+ channel

↓ Ca2+ permeability, inhibiting release of hormones & NT’s

↓ Glutamate release,↑ GABA release

Diplopia, ataxia, coarsening of facial features, peripheral neuropathy

Fetal abnormalities, gingival hyperplasia, hirsutism

Highly bound to plasma protein,

drugs can displace it, causing a

transient increase.

Induces P450

Suppresses high-frequency repetitive firingby blocking VG Na+ channels.

Block some Ca2+ currents.

Binds to allosteric site on GABA_A receptor and prolongs opening of Cl^- channels

↓ Glutamate excitation

Selectively suppress abnormal neurons

Sedation, cognitive issues, ataxia, hyperactivity
(See CH 22 barbiturates)

Induces P450

Respiratory depression

Tried for virtually every seizure type, especially when attacks are difficult to control

Strong sedative effects – drug of choice only for infants

Blocks high-frequency firing of neurons through action on VG Na⁺ channels

Acts pre-synaptically to decreases release of glutamate

Agranulocytosis

Aplastic anemia

Fetal abnormalities

Induces CYP450

Tricyclic used for bipolar depression

Prolongs inactivation of VG-Na⁺ channels

Acts presynaptically on VG Ca⁺² channels, ↓ glutamate release by blocking AMPA receptor

Dizziness, headache, diplopia, nausea, somnolence, skin rash;

Steven-Johnson syndrome
potentially life-threatening dermatitis in 1-2% of pediatric pts

Focal epilepsy, partial seizures,
absence and myoclonic seizures in children

bipolar disorder

Bind avidly to the α₂δ subunit of VG Ca⁺² channels, decreasing Ca⁺² entry = ↓ synaptic release of glutamate

↑ in brain GABA concentration

Somnolence, dizziness, ataxia, headache, tremor

Neuropathic pain

GABA analog

Blocks NMDA receptor

Potentiates GABA_A receptor response

Aplastic anemia and severe hepatitis at unexpectedly high rates

3^rd line drug for refractory cases of partial seizures
Lennox-Gastaut syndrome seizures

Enhances slow inactivation of voltage-gated Na⁺ channels

Binds to collapsing-response mediator protein, CRMP-2, thereby blocking the effect of neurotrophic factors on axonal/dendritic growth

Dizziness, headache, nausea, diplopia

Partial-onset seizures in patients with epilepsy 16 years or older

Binds selectively to the synaptic vesicular protein SV₂A; modifies synaptic release of glutamate and GABA through vesicular function

Somnolence, asthenia, ataxia, dizziness

myoclonic seizures of juvenile epilepsy

Inhibits reuptake of GABA by blocking the GAT-1 transporter in forebrain and hippocampus, prolongs inhibitory action of GABA

potentiation of tonic inhibition

Nervousness, dizziness, tremor, difficulty in concentrating, depression
Excessive confusion, somnolence, or ataxia; rarely psychosis

May cause seizures in some

patients (those who are taking it

for other reasons)

Blocks repetitive firing by blocking voltage gated Na+ channels; Potentiates GABA's inhibitory effect.

Block AMPA receptors
Multiple actions on synaptic function, probably via action on phosphorylation of VG and ligand-gated ion channels

Somnolence, fatigue, dizziness, cognitive slowing, paresthesias, nervousness, confusion

acute myopia, glaucoma

Lennox-Gastaut syndrome, West’s syndrome, absence seizures, migraine headaches

Blocks the Na+ and Ca2+ channels

Steven-Johnson syndrome

Infantile spasms and certain myoclonias

Reduces low threshold Ca⁺² currents (T-type). This removes the pacemaker current in neurons that generate the rhythmic cortical discharge of an absence attack.

Gastric distress – pain, nausea, vomiting
lethargy

Absence seizures

Blocks high-frequency repetitive firing (Na+ currents) and NMDA receptor mediated excitation.

↓ GABA

↓ Histone deacetylase (changes genetranscription)

GI complaints, fine tremor, pancreatitis

hepatotoxicity (may be fatal, especially for patients <2 or on multiple meds)

Spina bifida & other fetotoxicities

Absence seizures, very effective in controlling myoclonic seizures, generalized tonic-clonic, partial

Bipolar disorder, migraine prophylaxis

↑ threshold for seizure discharges after repetitive thalamic stimulation.

↓ the Ca2+ current and inhibits the pacemaker action of thalamic neurons (like ethosuxamide)

Sedation

*Teratogenic*

Absence

do NOT use in pregnancy

Potentiates GABA_A responses

Sedation, tolerance
children may have paradoxical hyperacitivtity (like barbituates)

Diplopia, nystagmus

IV or rectally to stop continuous seizures, especially generalized tonic-clonic status epilepticus

Inhibits carbonic anhydrase; causes mild acidosis in the brain, lowers depolarizing action of bicarbonate ions moving out of neurons via GABA ion channels.

Tolerance

Altered taste

seizure exacerbations during

menses