Transcript Chapter 15 - The Red Zone

CHAPTER 15
Antiepileptic Drugs
Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Epilepsy
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Seizure
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Convulsion
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Brief episode of abnormal electrical activity in
nerve cells of the brain
Involuntary spasmodic contractions of any or all
voluntary muscles throughout the body, including
skeletal and facial muscles
Epilepsy
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Chronic, recurrent pattern of seizures
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Epilepsy (cont’d)
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Primary (idiopathic)
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Cause cannot be determined
More than 50% of epilepsy cases
Secondary (symptomatic)
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Distinct cause is identified
• Trauma, infection, cerebrovascular disorder
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Classification of Epilepsy
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Partial-onset seizures
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Generalized-onset seizures
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Simple (formerly known as petit mal seizures)
Complex
Secondary generalized tonic-clonic
Formerly known as grand mal seizures
Unclassified seizures
Status epilepticus
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Antiepileptic Drugs (AEDs)
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Also known as anticonvulsants
Goals of therapy
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To control or prevent seizures while maintaining a
reasonable quality of life
To minimize adverse effects and drug-induced
toxicity
AED therapy is usually lifelong
Combination of drugs may be used
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Antiepileptic Drugs (cont’d)
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Single-drug therapy started before
multiple-drug therapy is tried
Serum drug concentrations must be
measured
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Therapeutic drug monitoring
Patients who are seizure free for 1 to 2 years
may be able to discontinue antiepileptic
therapy
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Mechanism of Action
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AED therapy must:
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Prevent generation and spread of excessive
electrical discharge from abnormally functioning
nerve cells
Protect surrounding normal cells
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Mechanism of Action (cont’d)
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Exact mechanism of action is not known
AEDs are thought to alter movement of
sodium, potassium, and calcium ions across
nerve cells in the brain
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Reduce nerve’s ability to be stimulated
Suppress transmission of impulses from one
nerve to the next
Decrease speed of nerve impulse conduction
within a neuron
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Mechanism of Action (cont’d)
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Overall effect
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Neurons are stabilized
Neuron hyperexcitability is decreased
Spread of excessive nerve impulses is decreased
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Antiepileptic Drugs:
Indications
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Prevention or control of seizure activity
Long-term maintenance therapy for chronic,
recurring seizures
Acute treatment of convulsions and status
epilepticus
Other uses
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Antiepileptic Drugs
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Numerous adverse effects—vary per drug
Adverse effects often necessitate a change in
medication
Black box warning as of 2008
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Suicidal thoughts and behavior
Long-term therapy with phenytoin may cause
gingival hyperplasia, acne, hirsutism, and
Dilantin facies
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Antiepileptic Drugs (cont’d)
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Barbiturates, such as phenobarbital (Luminal)
carbamazepine (Tegretol)
valproic acid (Depakene)
felbamate (Felbatol)
Hydantoins, such as phenytoin (Dilantin) and
fosphenytoin
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Antiepileptic Drugs (cont’d)
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Succinimides, such as ethosuximide
(Zarontin)
Benzodiazepines (clonazepam and
clorazepate)
gabapentin (Neurontin)
lamotrigine (Lamictal)
pregabalin (Lyrica)
levetiracetam (Keppra)
topiramate (Topamax)
tiagabine (Gabitril)
Others
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Nursing Implications
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Assessment
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Health history, including current medications
Drug allergies
Liver function studies, CBC
Baseline vital signs
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Nursing Implications (cont’d)
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Oral drugs
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Take regularly, same time each day
Take with meals to reduce GI upset
Do not crush, chew, or open extended-release
forms
If patient is NPO for a procedure, contact
physician regarding AED dosage
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Nursing Implications (cont’d)
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Intravenous forms
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Follow manufacturer’s recommendations for IV
delivery—usually given slowly
Monitor vital signs during administration
Avoid extravasation of fluids
Use only normal saline with IV phenytoin
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Nursing Implications (cont’d)
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Teach patients to keep a journal to monitor:
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Response to AED
Seizure occurrence and descriptions
Adverse effects
Instruct patients to wear a medical alert tag or
ID
AEDs should not be discontinued abruptly
Driving may be impaired until drug levels
stabilize
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Nursing Implications (cont’d)
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Teach patients that therapy is long term and
possibly lifelong (not a cure)
Monitor for therapeutic effects
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Decreased or absent seizure activity
Monitor for adverse effects
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Mental status changes, mood changes, changes
in level of consciousness or sensorium
Eye problems, visual disorders
Sore throat, fever (blood dyscrasias may occur
with hydantoins)
Many others
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