Transcript cns – antiepileptic drugs

CNS – ANTIEPILEPTIC DRUGS
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Compare and contrast the terms seizure, convulsion
and epilepsy.
Discuss the indications for antiepileptic therapy (AED).
Compare and contrast the first line drugs of choice for
AED.
Discuss the nursing process related to the care of the
patient receiving AEDs in acute and chronic situations.
CNS – ANTIEPILEPTIC DRUGS
INTERNATIONAL CLASSIFICATION OF
SEIZURES
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Partial Seizures – short alterations of consciousness; repetitive
unusual movements (chewing or swallowing); psychologic changes;
confusion
Simple Seizures – No impaired consciousness; motor symptoms of
face, arm or legs; hallucinations of sight, hearing, or taste; tingling
sensation; ANS changes; personality changes
Complex Seizures – Impaired consciousness; memory impairment;
behavioral effects; purposeless behaviors; aura, unreal feelings, bizarre
behavior
Generalized Seizures – Temporary lapses in consciousness; staring
off into space; rhythmic movements of eyes, head, or hands; may have
tonic, clonic, myoclonic, atonic, or tonic-clonic seizures; brief loss of
consciousness without confusion; head drop or falling down symptoms
CNS – ANTIEPILEPTIC DRUGS
SYNDROME OF CNS DYSFUNCTION
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Convulsion – Involuntary spasmodic
contractions of any or all voluntary muscles
throughout the body, including skeletal and facial
muscles. Postictal state
Seizures – Brief episode of abnormal electrical
activity in the nerve cells of the brain -- detected
on EEG
Epilepsy – Chronic, recurrent pattern of
seizures
CNS
ANTIEPILEPTIC DRUGS /ANTICONVULSANT DRUGS
Terms overlap and are used
interchangeably to achieve the goal of
maintaining a reasonable quality of life.
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Antiepileptic Drugs: management of all types
of epilepsy, not just convulsions (AED Therapy)
Anticonvulsant Drugs: used to prevent the
seizures typically associated with epilepsy.
CNS – ANTIEPILEPTIC DRUGS
MECHANISM OF ACTION
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ION Theory – movement of K+, Na+, Ca+, Mg+:
Stabilizes neurons:
from becoming hyperexcited
 prevents excessive impulses to adjacent neurons
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1. Increase threshold of activity in the motor cortex
Makes it more difficult to excite; reduces response
2. Depress the seizure discharge from its origin
Suppress transmission of impulses from one nerve to the next
3. Decrease the speed of nerve impulse conduction
within a given neuron
CNS – ANTIEPILEPTIC DRUGS
INDICATIONS
Prevention or control of seizure activity
 Long-term maintenance treatment of epilepsy
 Acute treatment of convulsions and status epilepticus
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Status epilepticus: common seizure disorder –
life-threatening emergency characterized by tonic-clonic convulsions
that occur in succession.
 Loss of consciousness, hypotension, hypoxia, cardiac dysrhythmias –
brain damage and death may quickly result
 Once controlled, long term therapy is begun to prevent future
seizures
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Brain Surgery - Head injuries = prophylactic AED
Therapy
CNS – ANTIEPILEPTIC DRUGS
CONTRAINDICATIONS
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Known drug allergy
Pregnancy – consider risks to mother & infant if
untreated
CNS – ANTIEPILEPTIC DRUGS
DRUGS OF FIRST CHOICE
AED Therapy
Therapeut
ic Level
(mcg/mL)
Adverse Effects
carbamazepine
(Tegretol)
3-14
N/V; drowsiness; dizziness; orthostatic
hypotension; hypertension; dyspnea;
edema; nephrotoxicity; hepatotoxicity;
blood dyscrasias; dermatologic reactions
phenytoin
(Dilantin)
10-20
Cardiac dysrhythmias; hypotension; N/V
indigestion; sedation, drowsiness, dizziness,
blurred vision, fatigue, lethargy; confusion;
gingival hyperplasia; hyperglycemia; blood
dyscrasias; hepatoxicity; dermatologic
reactions
primidone (Mysoline) 5-12
Sedation; drowsiness; dizziness; blurred vision;
blood dyscrasias; paradoxical excitability
valproic acid
(Depakote)
Drowsiness; N/V; tremor; weight gain;
transient hair loss; blood dyscrasias;
hepatotoxicity; pancreatitis
50-100
CNS – ANTIEPILEPTIC DRUGS
Treatment of Status Epilepticus
AED Therapy
Dose Onset
mg/kg
Adverse Effects
diazepam
(Valium)
0.3-0.5 3-10 mins
Apnea, hypotension, somnolence
Fosphenytoin
(Cerebyx)
15-20
15-30 mins Cardiac dysrhythmias,
hypotension
Lorazepam
(Ativan)
0.050.1
1-20 mins
Phenobarbital
15-20
10-30 mins Apnea, hypotension, somnolence
Phenytoin
(Dilantin)
15-20
5-30 mins
Apnea, hypotension, somnolence
Cardiac dysrhythmias,
hypotension
CNS – ANTIEPILEPTIC DRUGS
BENZODIAZEPINES
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Actions
 Not fully understood
 May enhance the inhibitory effects of GABA in postsynaptic
clefts between nerve cells
Uses
 Diazepam (Valium), clonazepam (Klonopin),
clorazepate (Tranxene), lorazepam (Ativan)
 Diazepam - drug of choice for status epilepticus
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must be given intravenously -- slowly
never mixed with any other medication
Therapeutic outcomes
 Reduced frequency of seizures, reduced injuries
 Minimal adverse effects from therapy
CNS – ANTIEPILEPTIC DRUGS
HYDANTOINS
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Actions – mechanism unknown
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phenytoin (Dilantin) – most commonly used
ethotoin (Peganone)
fosphenytoin (Cerebyx)
Uses
 Anticonvulsants used to control tonic-clonic seizures
 CAUTION:
Phenytoin must be administered slowly
 Do not mix with other medications in the same syringe
 Dilute only with 0.9% NaCl to avoid precipitation
 Infuse slowly <150mg/min
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CAUTION: toxicity may cause nystagmus
 CAUTION: infiltration causes sloughing of tissue
Therapeutic outcomes
 Reduced frequency of seizures, reduced injuries
 Minimal adverse effects from therapy
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CNS – ANTIEPILEPTIC DRUGS
CARBAMAZEPINE
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Actions -- carbamazepine (Tegretol)
Blocks up the reuptake of norepinephrine
 Decreases release of norepinephrine and rate of
dopamine and GABA turnover
 Mechanisms of action as anticonvulsant are unknown
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Uses
Used in combination with other anticonvulsants to
control tonic-clonic seizures
 Not effective for myoclonic or absence seizures
 Should not be given with grapefruit – increased levels
of the AED
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Therapeutic outcomes
Reduced frequency of seizures, reduced injuries
 Minimal adverse effects from therapy
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CNS – ANTIEPILEPTIC DRUGS
SUCCINIMIDES
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Actions ethosuximide (Zarontin),
methsuximide (Celontin)
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Uses
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Mechanism of action unknown
To control absence (petit mal) seizures
Therapeutic outcomes
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Reduced frequency of seizures, reduced injuries
Minimal adverse effects from therapy
CNS – ANTIEPILEPTIC DRUGS
TOPIRAMATE
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Actions topiramate (Topomax)
Mechanisms of action are unknown
 May prolong blockade of sodium channels, enhance
activity of GABA, and antagonize certain
neurotransmitter receptors
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Uses
Used in combination with other anticonvulsants to
control tonic-clonic seizures
 Prevention of migraine headaches
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Therapeutic outcomes
Reduced frequency of seizures and injuries
 Minimal adverse effects from therapy
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CNS – ANTIEPILEPTIC DRUGS
PRIMIDONE
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Actions primidone (Mysoline)
Metabolized into phenobarbital and PEMA - both
active anticonvulsants
 Exact anticonvulsant mechanism of action is
unknown
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Uses
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Used in combination with other anticonvulsants to
treat tonic-clonic seizures
Therapeutic outcomes
Reduced frequency of seizures and injuries
 Minimal adverse effects from therapy
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CNS – ANTIEPILEPTIC DRUGS
GABAPENTIN
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Actions gabapentin (Neurontin)
Mechanisms of action are unknown
 Does not appear to enhance GABA
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Uses
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Used in combination with other anticonvulsants to
control partial seizures
Therapeutic outcomes
Reduced frequency of seizures
 Minimal adverse effects from therapy
 Also used for pain reduction – shingles, peripheral
neuropathy – nerve pain
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CNS – ANTIEPILEPTIC DRUGS
NURSING IMPLICATIONS
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Nurses may play an important role in diagnosis and
treatment
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Comprehensive history – allergies/medication reconciliation
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Describe seizures – precipitating events, duration/frequency,
intensity of the seizure activity, postictal behavior – observe &
record
Safety – positioning – assist pt during seizure, proper supplies
 Medication administration guidelines – specific for IV meds
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Lab values – check therapeutic blood levels on admission
 Patient and family support: discuss lifestyle and feelings with
patient
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CNS – ANTIEPILEPTIC DRUGS
PATIENT EDUCATION
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Medication:
adherence to prescribe regimen
 Do not Stop Abruptly – Life Time Treatment - Rebound
Convulsions
 Medic Alert Bracelet
 Protective environment
 Driving – physician prescription/State laws
 Sedating effects of the drugs – may decrease with time
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Avoid alcohol & cigarettes
Photosensitivity with certain AEDs – sunscreen & protective
clothing
 Avoid stimulants
 Oral hygiene – hyperplasia
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CNS – ANTIEPILEPTIC DRUGS
REVIEW
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When caring for a patient with epilepsy who was
hospitalized and successfully treated for status
epilepticus, a precaution that the nurse institutes
includes:
a. placing oxygen and suction equipment at the bedside.
 b. assigning an assistant to stay with the patient at all times.
 c. keeping an airway available to insert as needed.
 d. instructing the patient to stay in bed and call for assistance
to go to the bathroom.
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CNS – ANTIEPILEPTIC DRUGS
REVIEW
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A nurse witnesses a patient with a seizure disorder as he
suddenly jerks his arms and legs with tonic-clonic type
movement, falls to the floor, temporary loss of
consciousness, which he regains immediately. The type
of seizure demonstrated by this patient and that the
nurse documents is:
a. atonic seizure
 b. myoclonic seizure
 c. complex partial seizure with automatisms
 d. generalized seizure
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