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Flashcards in Pharm anticonvulsants Deck (69)
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1
Q
definition of epilepsy
A
at least 2 unprovoked seizures separated by 24 hours
2
Q
what single events can precipitate seizusres
A
withdrawal of CNS depressants
acute neuro illness or toxic systemic
fever
3
Q
what is a simple partial seizure
A
minimal spread of abnormal discharge, normal consciousness, preserved awareness
4
Q
what is a complex partial seizure
A
localized onset but discharge becomes widespread, almost always involves limbic system
5
Q
characterstics of complex partial seizure
A
lip smacking, swallowing fubmling, scratching, memory loss or aberrant behavior
6
Q
secondarily generalized seizure
A
partial that immediately precedes a generalized tonic clonic seizure
7
Q
what is a generalized seixure
A
without evidence of localized onset, both brain hemispheres involved
8
Q
what is a grand mal seizure
A
generalized tonic clonic
sudden, sharp tonic contraction followed by rigidity and clonic movements
patient may cry, moan, lose sphincter control, bite tongue or develop cyanosis
9
Q
after grand mal seizure, patient may have
A
altered consciousness, drowsiness or confusion
10
Q
postictal Sx of seizure
A
grand mal
generalized tonic clonic
11
Q
what is an absence seizure
A
sudden onset and abrupt cessation, altered consciousness,
a blank stare
usually young children through adolescence
12
Q
myoclonic jerking
A
brief shock like muscle contractions
occur in wide variety of seizures
13
Q
atonic seizures
A
sudden loss of postural tone, head drop, fall to floor, slumping
many patients wear helmets to prevent head injury
14
Q
AED treatments
A
suppress seizures but do not cure of prevent epilepsy
15
Q
how do you switch AED Tx monotherapy
A
taper off initial AED after second AED is titrated to therapeutic level
16
Q
MOA AED
A
affect ion channel kinetics
augmenting inhibitory neurotransmission
modulating excitatory neurotransmission
17
Q
which AEDs are highly protein bound
A
phenytoin
tigabine
valproic acid
18
Q
how are AEDs cleared
A
hepatic metabolism
19
Q
Adverse effects AEDs
A
sedation, dizziness, blurred or double vision, difficulty concentrating and ataxia
20
Q
MOA phenytoin
A
blocks sustained high frequency firing action potentials due to preferential binding to and prolongation of inactivated state of Na channel
also dec glutamate and enhances GABA release
21
Q
PK phenytoin
A
not IM
erratic absorption
highly protein bound
low dose first order kinetics
high dose disproprotionate elimination
22
Q
use of phenytoin
A
partial seizures, generalized tonic-clonic seizures
23
Q
adverse effects phenytoin
A
diplopia, ataxia, nystagmus, sedation, gingival hyperplasia, hirsutism
24
Q
long term adverse effects phenytoin
A
worsening facial features, mild peripheral neuropathy
abnormalities in vit D metabolism causing osteomalacia
25
Q
cardiac effects of phenytoin
A
hypotension, bradycardia, cardaic arrhythmia, CV collapse, venous irritation and pain, thrombophlebitis
26
Q
DDI phenytoin
A
related to protein binding
sulfonamides by dispalce phenytoin from site increasing the amount of free drug!
CYP2C9, increased warfarin!!!
CYP3A4, increased risk pregnancy on oral contraceptives
27
Q
MOA carbamazepine
A
acts on Na Ch resulting in inhibition of high frequency repetitive firing
also acts presynaptically to decrease synaptic release of glutamate
28
Q
PK carbamezepine
A
autounduction, increased expression of CYPs and UGT
29
Q
use of carbamezapine
A
partial seizures, generalized tonic-clonic seizures, trigeminal neuralgia, mania in bipolar disorder
30
Q
adverse effects carbamazepine
A
diplopia, ataxia, mild GI upset, unsteadiness, drowsiness
hyponatremia and water intoxication
idiosyncratic blood dyscrasias
rash, sometimes stevens johnson
31
Q
what patients at higher risk stevens johnson syndrome reaction from carbamazepine
A
asians with HLA B*1502
32
Q
DDI carbamazepine
A
hepatic enzyme induction leading to increased metabolism of other drugs
33
Q
what drug inhibits carbamazepine clearance (increased levels)
A
valproic acid
34
Q
what drug has fewer DDI than carbamazepine
A
oxcarbazepine
35
Q
MOA phenobarbital
A
binds GABA and enhances GABA mediated current by prolonging Cl Ch
36
Q
MOA gabapentin
A
analogs of GABA
bind 2alphadelta on vNtype Ca Ch decreasing Ca, decreasing release of glutamate
37
Q
use of gabapentin
A
partial seizures, generalized tonic-clonic seizures, neuropathic pain
post herpetic neuralgia
38
Q
adverse to gabapentin
A
somnolence, dizziness, ataxia, HA, tremor
39
Q
MOA lamotrigine
A
like pheytoin suprres neurons through inactivation Na Ch
inhibits vCa Ch
40
Q
uses of lamotrigine
A
> 2y.o with partial seizures or generalized
also used for monotherpay partial seizures
adjunct in primary generalized tonic clonic
absence
bipolar
41
Q
adverse effects lamotrigine
A
dizziness, HA, diplopia, ataxia, nausea, somnolence, skin rash
42
Q
DDI lamotrigine
A
concentrations decrease with use oral contraceptives (E component)
may lead to contraceptive failure in P only pill
43
Q
MOA levetiracetam
A
binds to synaptic vesicular protein SV2A modifies synaptic release of glutamate and GABA through action on vesicular function
44
Q
use of levetiracetam
A
adjunct for partial seizures in adults and children
primary generalized tonic clonix
myoclonic seizures of jevenile epilipsy
45
Q
adverse effects levetiracetam
A
somnolence, asthenia, ataxia dizziness
46
Q
adverse effect tigabine
A
cause seizures in some patients who take tiagabine for bipolar disorder, anxiety and neuropathic pain
47
Q
MOA ethosuximide
A
reduce threshold Ca T type which are pacemaker for thalamic neurons
48
Q
use of ethosuximide
A
absence seizures
49
Q
adverse effects ethosuximide
A
gastric distress, pain , nausea and vomiting
50
Q
DDI ethosuximide
A
valproic acid can inhibit metabolism of ethosuximide
51
Q
MOA valproic acid and Na valporate
A
blocks firing of neurons through Na currents
blocks NMDA R mediated excitation
increased levels GABA in brain
52
Q
use of valproic acid
A
absence seizures
myoclonic seizures
generalized tonic clonic seizures
partial seizures
status epilepticus (IV
bipolar disorder
migraine prophylaxis
53
Q
adverse effects valproic acid
A
nausea, vomiting, abdominal pain, heartburn
fine tremor
weight gain, hair loss
hepatotoxicity and thrombocytopenia
54
Q
what must you monitor if put patient on valproic acid
A
liver function because of hepatotoxicity
55
Q
MOA diazepam
A
bind GABAa R
increase GABA Cl Ch to increase inhibitory membrane potentials
56
Q
PK diazepam
A
lipophilic, goes to CNS in sec when IV
redistributes to fat quickly
57
Q
why do you give a longer acting AED after giving diazepam
A
prevent seizure recurrence
58
Q
therapeutic use diazepam
A
status epilepticus, adjunct, myoclonic, partial, and generalized tonic clonic seizures
59
Q
adverse effects to diazepam
A
sedative
drowsiness
ataxia
behavior disorders
60
Q
first DOC for partial seizures and secondarily generalized
A
carbamazepine
or lamotrigrine
or oxcarbazepine
or levetiracetam
61
Q
second line of drugs for partial seizures or secondarily generalized
A
topiramate, gabapentin, pheytoin
62
Q
first DOC for primary generalized tonic clonic or grand mal
A
valporate
lamotrigine
levetiracetam
63
Q
second line for grand mal seizure
A
carbamazepine, phenytoin
64
Q
first DOC for absence seizures
A
ethosuximide
or valproate
65
Q
second DOC for absence seizures
A
lamotrigine
levetiracetam
66
Q
first DOC for atypical absence of myoclonic or atonic seizures
A
valproate
lamotrigine
levetiracetam
67
Q
teratogenicity of AED
A
increased risk congenital malformations
68
Q
phenytoin teratogenicity
A
fetal hydantoin syndrome (abnormal skull, facial features, growth deficiency, underdeveloped nails or mild developmental delays)
69
Q
what AED indicated in spina bifida
A
valproate