Pharm 15 - Seizure Flashcards
Inhibit electrical neurotransmission by use-dependent block of neuronal voltage-gated sodium channel. Strong treatment of focal and secondary generalized seizures.
Sodium Channel Inhibitor Mechanism
Sodium Channel Inhibitor: slows the rate of recovery, increasing the threshold for firing. Targets channels that open and close at high frequencies. Major drug of choice for focal and tonic-clonic seizures. Affected by p450 drugs.
Phenytoin
Sodium Channel Inhibitor: slows the rate of recovery. Used for focal seizures because it suppresses seizure foci and prevents spread. Metabolism is linear so is good for potential drug interactions. Number one for focal seizures.
Carbamazapine
Sodium Channel Inhibitor: Can be used for focal, tonic-clonic, and absence seizures (after valproic acid and ethosuximide).
Lamotrigine
inhibit the low-threshold T-type calcium channel
Ethosuximide and valproic acid
inhibits the high-voltage-activated (HVA) calcium channel
Gabapentin
Inhibit the low-threshold T-Type Calcium Channel at high concentrations and slows Sodium channel recovery at low concentrations. It also inhibits the activity of enzymes that degrade GABA.
Valproic Acid
Inhibit the low-threshold T-Type Calcium Channel: First line for Absence Seizures and NOT effective for Focal or Tonic-Clonic Seizures.
Ethosuximide
Inhibits the high-voltage-activated (HVA) calcium channel which results in decreased neurotransmitter release.
Gabapentin
Potentiate GABA-mediated inhibition to increase chloride current through the channel
GABA CHANNEL POTENTIATOR Mechanism
Potentiate GABA-mediated inhibition to increase chloride current through the channel: Focal and tonic-clonic seizures.
Benzodiazepines and Barbituates
Potentiate GABA-mediated inhibition to increase chloride current through the channel: increases duration of Cl- channel opening. Used for focal and tonic-clonic seizures because it can make absence seizures worse.
Barbituate: Phenobarbital
prevents GABA mediated hyperpolarization of the thalamus and thereby indirectly inactivates the T-type Ca2+ channel.
Clonazepam
Benzodiazepines
Diazepam
Lorazepam
Midazolam
Clonazepam:
Glutamate Receptor Inhibitor: inhibits glycine binding site of NMDA receptor-ionophore complex, resulting in suppression of seizure activity. Has a lack of sedative effects.
Felbamate