Anticonvulsants Flashcards
what is a seizure?
sudden change in behavior dt abn synchronization and excessive electrical activity in the brain
during, neurons may fire as many times at 500 times a second (much faster than regular rate of 80x’s a sec)
definition of epilepsy?
recurrent, unprovoked seizures BUT there are multiple causes for a seizure to occur in individuals who do not have epilepsy
ssxs most seizures cause? other ssxs?
LOC, notable facial grimacing, jerking or shaking of body
others may present only w/staring spells, visual disturbances, disruption of smell or taste, some will experience an aura before onset of seizure
first aid for seizures?
cushion head remove any eyewear loosen tight clothing turn on side time seizure with a watch don't put anything in mouth look for ID don't hold down as seizure ends, offer help
environmental factors that can lead to increased likelihood of seizures?
flashing lights sleep deprivation EtOH consumption stress or anxiety illness
causes of non-epileptic seizures?
SOL in the brain head trauma drug SEs, toxicity, withdrawal fever meningitis, encephalitis metabolic/electrolyte abnormalities
classifications of seizures?
simple (no change in level of consciousness) or complex (change in level of consciousness)
partial/focal (one part or side of the body is affected) or generalized (entire body is affected)
can be further divided into simple partial, complex partial, generalized absence, generalized tonic, generalized clonic, generalized tonic-clonic, status epilepticus
60% of ppl w/epilepsy have what kind of seizure?
focal seizures
what will someone experience with a simple partial seizure?
will remain conscious but experience unusual feelings or sensations that can take many forms (fear, joy, anger, sadness out of context; hallucinations involving sight, sound, smell, taste, skin sensation)
what will someone experience in a complex partial seizure?
has a change in or loss of consciousness
may display strange, repetitious behaviors such as blinks, twitches, mouth movements, motions such as walking in a circle = automatisms
these seizures usu only last a few seconds
what will someone experience in absence seizures?
interruption in consciousness where person experiencing the seizure seems to become vacant and unresponsive for a short period of time
slight muscle twitching may also occur
sometimes referred to as petit mal seizures
what do tonic-clonic seizures produce as far as sxs?
stiffening of the body, repeated jerks of arms and/or legs as well as LOC
grand mal seizures
involve initial contraction of muscles (tonic phase) which may involve tongue biting, urinary incontinence and absence of breathing
followed by rhythmic muscle contractions (clonic phase)
“epileptic fit”
what is status epilepticus? when is a seizure considered an emergency?
refers to continuous seizure activity w/no recovery btw successive seizures
considered a medical emergency if lasts beyond 5 mins (or 2 mins longer than regular seizure length)
main 4 MOAs of antiepileptics?
sodium channel blockade calcium channel (T-type) blockade potentiate GABA (inhibitory neurotransmission) decrease glutamate (excitatory neurotransmission)
is it possible to determine who will experience SEs from anticonvulsants or at what does?
NO
how do anticonvulsants affect electrical d/cs?
either block initiation of electrical d/c from focal area or prevent the further spread of the abn electrical d/c to adjacent brain areas
3 first line anticonvulsants? 3 second line drugs? 3 new antiepileptic meds?
1st line: carbamazepine, sodium valproate, lamotrigine
2nd line: levetiracetam, topiramate, pregabaline
new: zonisamide, eslicarbazepine, retigabine
initial drug tx is meant to accomplish what two things? usu based on what?
meant to suppress or reduce the incidence of seizures
determine what type to use based on the seizures the individual is experiencing
basic rules for anticonvulsant therapy?
tx should be simple, consisting of monotherapy
“start low, increase slow”
6 drugs that are potentially effective against partial seizures?
carbamazepine/tegretol phenytoin/dilantin diazepam/valium primidone/mysoline valproic acid/depakote lamotrigine/lamactil
3 drugs that are potentially effective against abscene seizures (petit mal)
ethosuximide/zarontin
valproic acid/depakote
clonazepam/klonapin
what drug is used to tx epilepsy in children and adults? also approved for tx’ing what?
topiramate
also approved for prevention of migraines, bipolar d/o or to counteract wt gain associated w/numerous antidepressants
can also, also tx tremor, bulimia, OCD, alcoholism, smoking cessation, neuropathic pain, cluster h/a, cocaine dependence, borderline personality d/o
4 drugs potentially effective for tx’ing status epilepticus?
diazepam/valium
lrazepam/ativan
midazolam/versed
phenobarbital/phenobarb
what do you give to a pt who is having a status epilepticus episode? then what?
give benzodiazepine then restart on anti-seizure drug they have been on or start on phenytoin/dilantin
class of phenobarbital/phenobarb? indications? MOA? how to give? onset and half-life? initial drug of choice in what population? metabolism?
class: barbiturate anticonvulsant
indication: generalized seizures
MOA: enhanced GABA activity
give IV/PO
relatively slow onset and very long half-life
may be initial drug of choice in children w/seizures
metabolized by P450 enzymes in liver
rarely used since the development of phenytoin/dilantin
phenobarbital sodium injection can be used to tx what?
can be used to stop acute convulsions or status epilepticus but benzo such as lorazepam or diazepam usu tried first
SEs of phenobarbital/phenobarb? stimulation of what system causes increased metabolism?
SE: CNS depression, drowsiness, assoc w/lower IQ scores in kids undergoing chronic tx
stimulation of P450 enzymes can increase metabolism of other drugs and concurrent phenobarb use can lower serum concentration of multiple drugs
class of primidone/mysoline? MOA? indications?
class: barbiturate anticonvulsant
MOA: exact MOA unknown but pheno is a known metabolite of primidone so GABA mediated inhibition is considered as chief MOA
indication: all types of seizure d/os except absence seizures
how to give primidone/mysoline? plasma half life? SEs? category?
give PO
metabolized in liver
10-12 hrs is plasma half life but half life of metabolites if greater than 48 hrs
SEs: nausea, anorexia, H/A, vertigo, ataxia
category D (do not use in PG)
class of diazepam/valium? MOA? indications?
class: benzodiazepine anticonvulsant
MOA: increased sensitivity to GABA receptor sites w/subsequent increased chloride influx which serves to inhibit CNS synaptic transmission
indications: grand mal seizures, status epilepticus, seldom if ever used as a chronic tx choice for seizures, anxiety, panic d/o
how does diazepam effect GABA levels and glutamate decarboxylase activity?
has NO effect on GABA levels and no effect on glutamate decarboxylase activity but has slight effect on gamma-aminobutyric acid transaminase activity
MOA of benzodiazepines?
act via benzodiazepine binding sites as Ca2+ channel blockers and significantly inhibit depolarization-sensitive Ca uptake in rat nerve cell preparations
class of clonazepam/klonopin? MOA? indications? how to give? duration of action? SEs?
class: benzodiazepine anticonvulsant
MOA: increased sensitivity to GABA receptor sites w/subsequent increased chloride influx which serves to inhibit CNS synaptic transmission
indications: alt to ethosuximide or valproic acid for absence seizures, status epilepticus
give PO, long acting
SEs: drowsiness, altered mentation, additive w/CNS depressants, marked abuse potential, tolerance develops
class of phenytoin/dilantin? MOA? indications? how to give? onset? half life? what do you need to monitor?
class: anticonvulsant MOA: reduces Na and Ca currents across neuronal membranes indications: prophylaxis for all types of seizures except absence seizures give PO/IV/IM slow onset long half life tolerance can develop need to monitor drug levels, CBC, LFTs
SEs of phenytoin/dilantin? phenytoin adverse effects?
SEs: nystagmus, ataxia, gingival hyperplasia, possible hepatotoxicity, possibly bone marrow suppression, IV admin may cause hypotension and arrhythmias P-450 interactions Hirsutism Enlarged gums Nystagmus Yellow-browning of skin Teratogenicity Osteomalacia Interference w/B12 metabolism (anemia) Neuropathies (vertigo, ataxia, H/A)
class of carbamazepine/tegretol? MOA? indications?
class: anticonvulsant
MOA: reduction of Na and Ca currents across neuronal membranes
indications: prophylaxis against all types of seizures except absence seizures, chronic pain such as trigeminal neuralgia, post-herpetic neuralgia, schizophrenia, bipolar d/o
how to give carbamazepine/tegretol? SEs? what pt population can not be given carbamazepine/tegretol? what do you need to monitor?
give PO
SE: vertigo, N/V, possible bone marrow suppression and aplastic anemia
should never be given to pts on monoamine oxidase inhibitors as combo increases risk for all associated SEs and increases risk for hypertensive crisis
need to monitor CBCs, LFTs
class of valproic acid/depakote? MOA? indications? how to give? seizure effect when combined w/other anticonvulsants?
class: anticonvulsant
MOA: unknown, enhancement of GABA transmission has been postulated
indications: all seizure types, particularly in absence seizures and combined seizure conditions, bipolar d/o, chronic pn syndromes
one of the drugs you can add to monotherapy if one drug doesn’t work
give PO/IV
additive anti-seizure effects when combined w/other anticonvulsants
how can valproate tx bipolar d/o instead of lithium?
affects fxn of GABA, by enhancing transmission, making it an alternative to lithium salts in the tx of bipolar d/o
MOA of valproic acid/depakote?
blocks the voltage-gated sodium channels and T-type calcium channels –> make it a broad-spectrum anticonvulsant drug
SEs of valproic acid/depakote? what vitamin does it effect? effects on PG women and babies?
SE: nausea, insomnia, anxiety, potential for severe hepatotoxicity
known to be antagonist of folic acid
in PG women irreversible birth defects are 3-10x’s higher than average
defects such as anencephaly
class of ethosuximide/zarontin? indications? MOA? give how? what other anticonvulsant drug does it increase? what line in therapy is it for absence seizures?
class: anticonvulsant
indications: absence seizures
MOA: unknown, possibly affects T-type Ca ion channels
give PO
ethosuximide increases phenytoin levels
considered first line drug fro treating absence seizures b/c less hepatotoxic than valproic acid
SEs of ethosuximide/zarontin?
SE: H/A, N/V, fatigue, ataxia, blurred vision, confusion, skin rashes, insomnia, gingival hyperplasia (mild), notable for possible hepatotoxicity and lupus-like syndrome, intractable hiccoughs
class of gabapentin/neurontin? MOA? indications? absorption is decreased by concurrent use with what?
class: anticonvulsant, atypical analgesic
MOA: potentiate GABA, affects N-type Ca channels, mimics chemical structure of GABA but doesn’t act on brain receptors, halts the formation of new synapses
indications: adjunctive tx of partial seizures, chronic pain syndromes such as post-herpetic neuralgia, migraine h/as
reduce dose w/renal dysfxn, absorption decreased by concurrent use of antacids
SEs of gabapentin/neurontin? special use for withdrawal tx?
SE: somnolence, dizziness, ataxia, H/A, other CNS effects
1200 mg at bedtime taken for 40-60 days has been effective in reducing withdrawal sxs and diminishing desire for methamphetamines and/or cocaine
tx for alcohol dependence?
flumazenil (IV), hydroxyzine, gabapentin
class of lamotrigine/lamactil? MOA? indications? SEs?
class: anticonvulsant
MOA: unknown, may stabilize neurons by decreasing sensitivity to excitatory effects of glutamate and aspartate
indications: tonic-clonic (grand mal) seizures, complex partial seizures and seizures resistant to other drug txs
give PO
SE: dizziness, H/A, rashes, diplopia, somnolence, ataxia
first drug approved by FDA for tx’ing type I bipolar d/o?
lamotrigine
class of levetiracetam/keppra? MOA? indications? other potential indications?
class: anticonvulsant
MOA: unknown, may stabilize neurons by inhibition of calcium movement through presynaptic Ca channels
indications: tonic-clonic seizures, complex partial seizures, seizures resistant to other drug txs, neuropathic pain
has potential benefits for other psychiatric conditions such as Tourette’s, Alzheimer’s, autism, bipolar
SEs of levetiracetam/keppra?
SE: generally well tolerated by can cause drowsiness, weakness, unsteady gait, coordination problems, H/A, mood changes, nervousness, loss of appetite, vomiting, diarrhea, constipation and rare reports of possible changes in skin pigmentation
two meds for partial seizures?
lamotrigine/lamictal
phenytoin/dilantin
4 meds for grand mal seizures?
valproic acid/depakote
lamotrigine/lamactil
levetiracetam/keppra
topiramate/topamax
med for absence seizures?
ethosuximide/zarontin
2 meds for myoclonic seizures?
valproic acid
clonazepam
med for febrile seizures?
anti-pyretic such as ibuprofen
two drugs for status epilepticus?
diazepam/valium
IV lorazepam/ativan
all current drugs, with the exception of what can be used in the tx of complex partial seizures?
ethosuximide
4 drugs for generalized/tonic clonic seizures?
valproate/depakote
lamotrigine/lamictal
levetiracetam/keppra
topiramate/topamax
drug for absence (petit mal) seizures?
ethosuximide/zarontin
for all anticonvulsants what does should you start at? what do you need to monitor? if initial monotherapy doesn’t work? tapering? discontinuing?
begin at low dose and titrate to desired effect or until limiting SEs develop
follow serum drug levels
switch to another drug if not effective at maximum dosing before you try 2 drug therapy
always try to taper the dosage
never discont abruptly or status epilepticus can be induced
other tx options for seizures that aren’t meds?
ketogenic diet vagus nerve stimulator brain neurostimulators surgery seizure responsive service pet
3 anticonvulsants that can be used in dual drug therapy?
valproic acid/depakote
gabapentin/neurontin
levetiracetam/keppra
