Antiepileptic Drugs

Question 1

Antiepileptic drugs limit the excitability of what channels/receptors?

Answer 1

Voltage-gated Na and Ca channels and Glu receptors

Question 2

Antiepileptic drugs enhance the inhibition of what system?

Answer 2

GABA system

Question 3

Membrane ion channel involved in action potential generation, and
stabilizes inactive state inhibiting recurrent depolarization

Answer 3

Voltage-gated sodium channel

Question 4

What 4 drugs have primary activity against the VG-Na channel?

Answer 4

Phenytoin, carbamazepine, oxcarbamazepine, lamotrigine

Question 5

What 3 drugs have secondary activity against the VG-Na channel?

Answer 5

Valproate, felbamate, topiramate

Question 6

Presynaptic membrane channels
in which blocking the influx of the name’s ion leads to less excitatory neurotransmitter release? Blocking this is useful in treating what type of pain?

Answer 6

Voltage-gated calcium channel. Neuropathic pain

Question 7

What are the two primary [high-voltage type-] VG-Ca channel blocking drugs?

Answer 7

Gabapentin and pregabalin

Question 8

Blocker of the T-type VG-Ca channel in the thalamus

Answer 8

Ethosuximide

Question 9

Name the 5 drugs with secondary activity against the VG-Ca channel

Answer 9

Topiramate, Felbamate, Phenobarbitol, Lamotrigine, Levitiracetam

Question 10

Receptors that lie on the post synaptic membrane of excitatory synapses and are ligand-gated cation channels (Ca, Na)

Answer 10

Glutamate receptors (AMPA & kainate receptors or NMDA receptor)

Question 11

NMDA receptor blocker

Answer 11

Felbamate

Question 12

Partially active as AMPA and Kainate receptor blocker

Answer 12

Topiramate

Question 13

Receptors are found on post synaptic membranes of inhibitory synapses and are ligand-gated Cl channels

Answer 13

GABA-A

Question 14

What drug and other class of drug activate the GABA-A receptors?

Answer 14

Phenobarbital and benzos

Question 15

What 5 drugs have secondary activity for the GABA-A system?

Answer 15

Valproate, Topiramate, Gabapentin, Leviteracetam, Felbamate

Question 16

VG-Na blockers have similar efficacies, similar metabolism and toxicities. They’re all hepatic enz inducers, especially lamotrigine. This drug makes ppl metab steroids faster and can thus lower the efficacy of what drugs and create a problem in ppl already taking teratogens?

Answer 16

Birth-control pills

Question 17

Carbamazepine toxicity: colloquial phrase but also list them

Answer 17

“Dizzy, drunk, dbl vision” = sedation, ataxia, diplopia

Question 18

Carbamazepine AEs

Answer 18

Rash (15%), rarely Stevens-Johnson, mild hepatic enz elevation, mild myelosuppression

Question 19

Carbamazepine uses

Answer 19

More effective for Complex Partial Epilepsy than Primary Generalized (preferred to Phenobarbitol, Phenytoin, Valproate which are also effective), useful in BAD and in treating neuropathic pain

Question 20

Pharm considerations for what drug?:
Highly protein bound
Hepatic metabolism
Autoinduction and heteroinduction
Effects other hepatically metabolized meds
Can cause contraceptive failure
Short half-life, extended release preparations
Toxicity thought to be due to epoxide metabolite

Answer 20

Carbamazepine

Question 21

Toxicity of Phenytoin (dilantin)

Answer 21

Dizzy, drunk, dbl vision = Dizziness, Nystagmus, Ataxia, Incoordination.

Question 22

AEs of phenytoin

Answer 22

Mild hepatotoxicity and myelosuppression,
Gingival hyperplasia, rash, hirsutism, Lupus-like reaction
Long term: cerebellar degeneration, peripheral neuropathy, osteoporosis

Question 23

IV infusion of phenytoin is limited by what side effect?

Answer 23

Hypotension

Question 24

Effective against Tonic-Clonic seizures of Primary Generalized Epilepsy or Partial onset and Secondarily Generalized seizures. Effective for acute seizures, even those that may not be related to epilepsy. Less effective for Absence, Myoclonic or Atonic seizures

Answer 24

Phenytoin

Question 25

What is the IV route of phenytoin useful in?

Answer 25

Status Epilepticus

Question 26

Pharmacologic Considerations of what drug?: Highly protein bound Hepatic metabolism Enzyme inducer Effects other hepatically metabolized meds. Can be associated with contraceptive failure Variable but longer half-life, usually once daily dosing

Answer 26

Phenytoin

Question 27

Designed to bypass cabamazepine epoxide. Less protein bound, less autoinduction, fewer interactions, less toxic, and longer half life

Answer 27

Oxcarbazepine

Question 28

Oxcarbazepine has the same efficacy and indications as carbazepine, notably usefulness in treating what?

Answer 28

Neuropathic pain

Question 29

Lamotrigine toxicity

Answer 29

Dizziness, Sedation, Ataxia, Diplopia

Question 30

AEs of lamotrigine

Answer 30

Dose-related rash (3%) (slow initial titration is important)

Question 31

If you don't know by now, what is the toxicity of Na-channel blockers?

Answer 31

Dizzy, drunk, dbl vision

Question 32

The list of indications are for what drug Na-channel blocker?: Effective for Primary Generalized Epilepsy, Partial Complex Epilepsy and secondary generalization, Absence. Indication for use in children. Less effective for and may exacerbate Myoclonic seizures. Useful in Bipolar Affective disorder. Useful in treating in neuropathic pain

Answer 32

Lamotrigine

Question 33

``` Pharmacologic Considerations for what drug? Hepatic metabolism Less protein bound Hepatic enzyme inducer Can cause contraceptive failure ```

Answer 33

Lamotrigine

Question 34

Lamotrigine competes for excretion and has synergistic action with what drug?

Answer 34

Valproic acid (Depakote)

Question 35

GABA transaminase binder (GABA-T, or GABA transaminase, makes GABA inactive in the presyn neuron)

Answer 35

Vigabatrine

Question 36

GABA reuptake inhibitor

Answer 36

Tiagabine

Question 37

Class of drugs used in Status Epilepticus that act at the GABA-A receptors and are dose limited by sedation

Answer 37

Benzos

Question 38

Benzo used in anesthesia or refractory Status Epilepticus

Answer 38

Midazolam

Question 39

Na-channel blocker and GABA-system enhancer with sedation and tremor as its toxicity

Answer 39

Valproate

Question 40

AEs of valproate

Answer 40

Nausea, wt gain, hair loss, hyperammonemia, teratogenic (4-8%)

Question 41

Effective against Absence, Myoclonic and Tonic-Clonic seizures of Primary Generalized Epilepsy as well as Partial onset and secondarily generalized seizures. Used in treatment of Bipolar Affective disorder. Used in Migraine prophylaxis

Answer 41

Valproate

Question 42

Valproate in IV route is useful in?

Answer 42

Status Epilepticus

Question 43

``` Pharmacologic Considerations for what drug? Highly protein bound Hepatic metabolism Rapidly Absorbed and Metabolized Short half-life Extended release preparations ```

Answer 43

Valproate

Question 44

GABA analogs, inhibits Ca currents

Answer 44

Gabapentin and pregabalin

Question 45

Gabapentin and pregabalin used as adjunctive tx for what type of epilepsy? More commonly used for treating what?

Answer 45

Partial complex. Neuropathic pain

Question 46

Toxicity of gabapentin is related to what?

Answer 46

Sedation

Question 47

Pharmacologic Considerations for what drug? Absorption limited at amino acid transporter in the intestine Limited protein binding No evidence of metabolism in humans No interaction with other medications Eliminated unchanged in urine No serious organ toxicity

Answer 47

Gabapentin

Question 48

Effective against Absence Seizures only

Answer 48

Ethosuximide

Question 49

Drug with a 40-60 hr half-life and side effects of transient nausea, sedation, and irritability

Answer 49

Ethosuximide

Question 50

Effective against Partial onset and secondarily generalized seizures as well as Primary Generalized Epilepsy. Effective for Migraine prophylaxis

Answer 50

Topiramate

Question 51

Toxicity of topiramate

Answer 51

Sedation, cognitive = 'word-finding'

Question 52

Adverse rxns of what drug?: Mild Metabolic Acidosis >> Respiratory compensation >> Mild Alkalosis >> Calcium ionization >> tingling (can be mitigated with Vit C). Modest wt loss, kidney stones, and rare acute glaucoma

Answer 52

Topiramate

Question 53

Effective against Partial onset and secondarily generalized seizures. Some evidence of activity against Primary Generalized Epilepsy. Named Keppra

Answer 53

Levetiracetam

Question 54

Mech of action of Levetiracetam

Answer 54

Binds to synaptic vesicle protein 2 resulting in less neurotransmitter release (Glu)

Question 55

Levetiracetam is well-tolerated with one toxicity, what is it?

Answer 55

Sedation

Question 56

AEs of irritability, aphasia, and thrombocytopenia characterize what drug?

Answer 56

Leveitracetam

Question 57

Lithium is used as what kind of stabilizer to tx what? Also tx's what type of HA?

Answer 57

Mood-stabilizer used to tx BAD and Cluster Headache

Question 58

Alters Sodium transport. Inhibits Sodium re-absorption proximal tubule. Renal clearance related to serum concentration. What drug?

Answer 58

Lithium

Question 59

Given Lithium's S.E.s, where is it contra'd?

Answer 59

In those with a arrhythmia or prone to dehydration

Question 60

Lithium interacts with what 3 drug classes?

Answer 60

Diuretics, ARBs, NSAIDs

Question 61

Toxicity of what drug? Lower level: sedation, dizzy, thirst, inc. urination, fine tremor. Higher level: “Giddiness”, ataxia, blurred vision, large amt of dilute urine.

Answer 61

Lithium

Question 62

In addition to being aware of ppl with arrythmias, what syndrome can be unmasked by lithium?

Answer 62

Brugada syndrome