Block 2 Lecture 5 -- ASDs Flashcards by Drew Spargo | Brainscape

Q

Indications for phenytoin:

A

1) focal seizures
2) generalized tonic-clonic
3) emergency status epilepticus

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Q

Indications for carbamazepine:

A

1) temporal lobe epilepsy

2) all others except absence

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Q

Indications for oxcarbazepine:

A

1) temporal lobe epilepsy

2) all others except absence

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Q

Indications for valproic acid:

A

1) absence

2) most others

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Q

Indications for lamotrigine:

A

all seizure types

– including generalized w/ absence attacks in children

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Q

Indications for topiramate:

A

1) focal seizures

2) generalized tonic-clonic

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Q

Indications for zonisamide:

A

1) focal seizures

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Q

Indications for lacosamide:

A

adjunct for focal-onset

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Q

Indications for gabapentin

A

focal seizures

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Q

Indications for pregabalin:

A

same as gabapentin

– focal seizures

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Q

Indications for ethosuximide:

A

absence seizures

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Q

Indications for retigabine:

A

adjunct for focal seizures

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Q

Indications for levetiracetam:

A

1) focal

2) generalized tonic-clonic

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Q

Indications for perampanel:

A

focal seizures

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Q

Indications for felbamate:

A

lennox-gastaut syndrome

retractable epilepsy with uncontrollable seizures

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Q

MoA of phenytoin

A

use-dependent Na+ channel blockade

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Q

MoA of carbamazepine

A

use-dependent Na+ channel blockade

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Q

MoA of oxcarbazepine

A

use-dependent Na+ channel blockade

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Q

MoA of lamotrigine

A

use-dependent Na+ channel blockade

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Q

MoA of lacosamide

A

use-dependent Na+ channel blockade

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Q

MoA of valproic acid

A

1) use-dependent Na+ channel blockade
2) stimulate GABA synthesis
3) inhibit GABA TA

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Q

MoA of topiramate

A

1) use-dependent Na+ channel blockade
2) augment GABA at GABAa
3) blockade of GluR (kainate and AMPA)

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Q

MoA of zonisamide

A

1) use-dependent Na+ channel blockade

2) t-type Ca channel blockade

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Q

MoA of Gabapentin

A

1) Ca channel blocker

2) GABAergic

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Q

MoA of pregabalin

A

Ca channel blocker

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Q

MoA of ethosuximide

A

Ca channel blocker

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Q

MoA of retigabine

A

K channel stabilizer

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Q

MoA of levetiracetam

A

SV2A binder

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Q

MoA of perampanel

A

AMPAr blocker (non-competitive)

Q

MoA of felbamate

A

NMDAr blocker

Q

Which ASDs exhibit PPB?

A

1) phenytoin (95%)
2) perampanel (95%)
3) valproic acid (90%)
4) levetiracetam (10%)

Q

Which ASDs are non-sedating?

A

1) phenytoin
2) lamotrigine
3) valproic acid
4) ethosuximide
5) felbamate

Q

What is the black box warning on felbamate?

A

1) aplastic anemia

2) acute hepatic failure

Q

Which ASDs are secreted as a glucuronide?

A

1) oxcarbazepine
2) lamotrigine
3) valproic acid

Q

Describe the metabolism of phenytoin.

A

1) non-linear (induces and saturates)
2) CYP2C9 + CYP2C19
3) t1/2 = 15-20h

Q

Describe the metabolism of carbamazepine.

A

1) CYP2C9, C19, 3A4
2) t1/2 = 12-30h
3) long-term t1/2 = 15hr

Q

Describe the metabolism of oxcarbazepine.

A

1) t1/2 = 1-2h

2) t1/2 (active mets) = 8-12h

Q

Describe the metabolism of lamotrigine.

A

t1/2 = 25h

Q

Describe the metabolism of lacosamide.

A

1) cyp2c19

2) t1/2 = 12-16h

Q

Describe the metabolism of valproic acid.

A

1) cyp2c19

2) t1/2 = 8-17h

Q

Describe the metabolism of topiramate?

A

t1/2 = 20-30h

Q

Describe the metabolism of zonisamide.

A

cyp3a4

t1/2 = 60+ hr

Q

Describe the metabolism of gabapentin.

A

hardly metabolized

t1/2 = 6h

Q

Describe the metabolism of pregabalin.

A

hardly metabolized

t1/2 = 6h

Q

Describe the metabolism of ethosuximide.

A

t1/2 = 60h

Q

Describe the metabolism of retigabine.

A

t1/2= 8-11h

Q

Describe the metabolism of levetiracetam.

A

hardly metabolized

t1/2 = 6-8h

Q

Describe the metabolism of perampanel.

A

1) cyp3a4

2) t1/2= 70 - 105h

Q

Describe the metabolism of felbamate

A

1) t1/2 = 20h

Q

Which ASDs are affected by CYP3A4 inducer and inhibitors?

A

1) perampanel
2) zonisamide
3) oxcarbazepine (less)
4) carbamazepine (more)
5) phenytoin

Q

Which ASDs are metabolized by CYP2C19?

A

phenytoin

lacosamide

Q

What are DDIs for lamotrigine?

A

hepatic inducers that increase glucuronidation and clearance

Q

What are DDIs of valproic acid?

A

1) PPB displacers

2) inhibits metabolism of phenobarb, phenytoin, carbamazepine

Q

What are DDIs for topiramate?

A

carbamazepine and phenytoin increase metabolism

Q

Which ASDs don’t have DDIs according to PK?

A

1) Ca channel blockers
2) K channel blockers (retigabine)
3) SV2a (keppra)
4) lacosamide

Q

What drugs are metabolized by CYP3A4?

A

1) ASDs
2) OCC
3) warfarin
4) corticosteroids

Q

What are CYP3A4 inhibitors?

A

1) valproic acid
2) cimetidine
3) erythromycin

Q

What are CYP3A4 inducers?

A

1) phenytoin
2) primidone
3) phenobarbitol

Q

What drugs displace PPB’ers?

A

1) valproate
2) phenytoin
3) salicylate

Q

What ASD has a serine residue?

A

lacosamide

Q

What drugs is cross-reactive to sulfonamide allergy?

A

zonisamide

Q

What drug is a monosaccharide derivative?

A

topiramate (fructopyranose)

Q

What drug has a triazine group?

A

lamotrigine

Q

What is phenytoin’s prodrug?

A

fosphenytoin

Q

How does retigabine work?

A

increases relative refractory period by binding to retigabine binding site on K+ channel

Q

What is the effect of SV2a modulation?

A

altered Glu and GABA release

Q

What drugs affect the AMPAr?

A

1) primary = perampanel

2) also: phenobarb, topiramate, lamotrigine

Q

What ASDs carry black box warnings?

A

1) perampanel: aggression, anger, homocidal
2) felbamate: aplastic anemia, acute hepatic failure
3) retigabine: retinal abnormalities and skin discoloration

Q

What is the intermediate in phenytoin metabolism?

A

reactive ARENE OXIDE

– probably causes the ADRs

Q

What ASDs act on CRMP2?

A

lacosamide has secondary activity