11) Antiepileptics Flashcards
What is the class for Phenytoin (Dilantin)
Voltage-gated Na channel stabilizer
What is the mechanism for Phenytoin (Dilantin)
Stabilize inactive conformation of Na channel
What are the therapeutics for Phenytoin (Dilantin)
Less effective for absence (particular pediatric), myoclonic, atonic seizures
What are the important side effects for Phenytoin (Dilantin)
Rash, gingival hyperplasia, hirsutism, lupus-like reaction; can cause contraceptive failure
What are the other side effects for Phenytoin (Dilantin)
Mild myelosuppression, increased LFT; long-term: cerebellar degeneration, peripheral neuropathy, osteoporosis
What are the miscellaneous for Phenytoin (Dilantin)
IV infusion limited by hypotension; hepatic enzyme inducer (both auto- and hetero-inducer), highly protein bound
What is the class for Carbamazepine (Tegretol)
Voltage-gated Na channel stabilizer
What is the mechanism for Carbamazepine (Tegretol)
Stabilize inactive conformation of Na channel
What are the therapeutics for Carbamazepine (Tegretol)
More effective for complex partial seizure than primary generalized; bipolar disorder; neuropathic pain
What are the important side effects for Carbamazepine (Tegretol)
Rash (rarely, Stevens-Johnson), mild myelosuppression, mild increase in LFTs; can cause contraceptive failure
What are the miscellaneous for Carbamazepine (Tegretol)
Hepatic enzyme inducer (both auto- and hetero-inducer); highly protein bound; must increase dose in 1-2 wks due to autoinduction; side effects likely due to epoxide metabolite
What is the class for Oxcarbamazepine (Trileptal)
Voltage-gated Na channel stabilizer
What is the mechanism for Oxcarbamazepine (Trileptal)
Stabilize inactive conformation of Na channel
What are the therapeutics for Oxcarbamazepine (Trileptal)
More effective for complex partial seizure than primary generalized; bipolar disorder; neuropathic pain
What are the important side effects for Oxcarbamazepine (Trileptal)
Rash (rarely, Stevens-Johnson), mild myelosuppression, mild increase in LFTs; can cause contraceptive failure
What are the miscellaneous for Oxcarbamazepine (Trileptal)
Designed to bypass carbamazepine epoxide; less protein-bound, less autoinduction, fewer interactions, less toxic, longer half-life than carbamazepine
What is the class for Lamotrigine (Lamictal)
Voltage-gated Na channel stabilizer
What is the mechanism for Lamotrigine (Lamictal)
Stabilize inactive conformation of Na channel
What are the therapeutics for Lamotrigine (Lamictal)
Primary generalized epilepsies, absence seizures; indicated in children; bipolar disorder; neuropathic pain
What are the important side effects for Lamotrigine (Lamictal)
Rash, (rarely, Stevens-Johnson): slow initial titration important; may lead to contraceptive failure
What are the miscellaneous for Lamotrigine (Lamictal)
May exacerbate myoclonic seizures; competes with valproic acid for excretion (potential synergy); hepatic enzyme inducer; not very protein bound
What is the mechanism for Valproate (Depakote)
Unknown; likely affects Na-gated channels and GABA system
What are the therapeutics for Valproate (Depakote)
Broad spectrum: absence, myoclonic, tonic-clonic, primary generalized, partial onset, and secondary generalized seizures (but not absence seizures); IV for status epilepticus; bipolar treatment, migraine and long-term cluster headache prophylaxis
What are the important side effects for Valproate (Depakote)
Weight gain, hair turnover, hyperammonemia (which can be mitigated with oral carnitine), teratogenicity, blood dyscrasias
What are the other side effects for Valproate (Depakote)
Pancreatitus
What is the class for Vigabatrin (Sabril)
GABAergic anti-epileptic
What is the mechanism for Vigabatrin (Sabril)
GABA transaminase binder (slows down intracellular breakdown of GABA)
What are the therapeutics for Vigabatrin (Sabril)
Anti-epileptic
What are the miscellaneous for Vigabatrin (Sabril)
Works on GABA-A
What is the class for Tigabine (Gabitril)
GABAergic anti-epileptic
What is the mechanism for Tigabine (Gabitril)
GABA reuptake inhibitor
What are the therapeutics for Tigabine (Gabitril)
Anti-epileptic
What are the miscellaneous for Tigabine (Gabitril)
Works on GABA-A
What is the class for Benzodiazapines
GABAergic anti-epileptic
What is the mechanism for Benzodiazapines
Bind GABA-A
What are the therapeutics for Benzodiazapines
Status epilepticus (refractory); anesthesia
What are the important side effects for Benzodiazapines
Sedation
What are the miscellaneous for Benzodiazapines
Long-term usefulness limited by tolerance
What is the class for Gabapentin (Neurontin)
GABA analog
What is the mechanism for Gabapentin (Neurontin)
Block presynaptic influx of Ca
What are the therapeutics for Gabapentin (Neurontin)
Adjunct for partial complex epilepsy; more commonly used for neuropathic pain
What are the important side effects for Gabapentin (Neurontin)
Sedation
What are the miscellaneous for Gabapentin (Neurontin)
Absorption limited by intestinal AA transporter (there is a Tm); limited protein binding; no metabolism or drug interaction in humans (so few side effects)
What is the class for Pregabalin (Lyrica)
GABA analog
What is the mechanism for Pregabalin (Lyrica)
Block presynaptic influx of Ca
What are the therapeutics for Pregabalin (Lyrica)
Adjunct for partial complex epilepsy; more commonly used for neuropathic pain
What is the class for Topiramate (Topamax)
Glutamate Receptor Blockers
What is the mechanism for Topiramate (Topamax)
Partial AMPA, Kainate Ca receptor blocker; secondary effect at voltage-gated Na channel, GABA system
What are the therapeutics for Topiramate (Topamax)
Partial onset seizures, secondary generalized seizures, primary generalized epilepsy; migraine prevention, long-term prevention of cluster headaches
What are the important side effects for Topiramate (Topamax)
Mild metabolic acidosis, kidney stones (due to some carbonic anhydrase activity); modest weight loss; rare acute glaucoma; sedation
What are the other side effects for Topiramate (Topamax)
Word-finding problems
What are the miscellaneous for Topiramate (Topamax)
Carbonic anhydrase activity leads to mild metabolic acidosis, which leads to respiratory compensation, which leads to mild alkalosis, which leads to calcium ionization, which leads to tingling; treat with vitamin C (acidify urine)
What is the class for Felbamate (Felbatol)
Glutamate Receptor Blockers
What is the mechanism for Felbamate (Felbatol)
NMDA receptor blocker; secondary effect at voltage-gated Na and Ca channels, GABA system
What are the therapeutics for Felbamate (Felbatol)
Partial onset seizures with or without secondary generalization; medically refractory epilepsy
What are the important side effects for Felbamate (Felbatol)
Uncommon but potentially fatal. Aplastic anemia, acute hepatic failure. Requires monitoring.
What is the class for Levetiracetam (Keppra)
Synaptic vesicle binder
What is the mechanism for Levetiracetam (Keppra)
Binds synaptic vesicle protein 2, leading to less NT release
What are the therapeutics for Levetiracetam (Keppra)
Partial onset seizures, secondary generalized seizures; maybe primary generalized epilepsy
What are the important side effects for Levetiracetam (Keppra)
Well tolerated; sedation, mostly; rarely, irritability, aphasia, thrombocytopenia
What is the class for Ethosuximide (Zarontin)
Voltage-gated Ca channel blocker
What is the mechanism for Ethosuximide (Zarontin)
Blocks T-type Ca-channels in thalamo-cortical circuits
What are the therapeutics for Ethosuximide (Zarontin)
Absence seizures only (and neuropathic pain)
What are the important side effects for Ethosuximide (Zarontin)
Nausea (transient), sedation, irritability
What are the miscellaneous for Ethosuximide (Zarontin)
Readily absorbed, minimal first pass metabolism; not protein bound
