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Chapter 52
Drug Therapy for Seizure
Disorders and Spasticity
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Seizure Disorders
• Seizure: brief episode of abnormal electrical activity in
the brain’s nerve cells
– May occur as single events
– May occur in a chronic, recurrent pattern
• Disorder known as epilepsy
• Convulsion: tonic–clonic type of seizure characterized by
spasmodic contractions of involuntary muscles
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Question
• Is the following statement True or False?
• Seizure and convulsion are different terms for the same
disorder.
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Answer
• False
• Rationale: A seizure is a brief episode of abnormal
electrical activity in the brain’s nerve cells. A convulsion
is a tonic–clonic type of seizure characterized by
spasmodic contractions of involuntary muscles.
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Epilepsy
• Usually requires long-term therapy
• Characterized by sudden, abnormal, hypersynchronous
firing of neurons
• Diagnosed by
– Clinical signs and symptoms of seizure activity
– Presence of abnormal brain wave patterns on EEG
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Epilepsy (cont.)
• Classifications
– Idiopathic
– Attributable to secondary cause
• Developmental defects
• Metabolic disease, birth injury
• Fever, acquired neurologic disorder
• Alcohol or other drug effects
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Question
• Is the following statement True or False?
• Epilepsy can be classified as either idiopathic or
attributable to secondary causes.
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Answer
• True
• Rationale: Epilepsy can be classified as either idiopathic
or attributable to secondary causes.
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Seizure Classifications
• Partial seizures
– Begin in a specific area of the brain
– Often indicate a localized brain lesion
• Birth injury
• Trauma
• Stroke
• Tumor
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Seizure Classifications (cont.)
• Partial seizures (cont.)
– Symptoms range from
• Simple motor and sensory effects
– To
• More complex abnormal movements and bizarre
behavior
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Seizure Classifications (cont.)
• Partial seizures (cont.)
– Movements are usually
• Automatic
• Repetitive
• Inappropriate to the situation
• Chewing, swallowing
• Aversive movements
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Seizure Classifications (cont.)
• Partial seizures (cont.)
– Simple partial seizures
• Consciousness not impaired
– Complex partial seizures
• Level of consciousness is decreased.
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Question
• Is the following statement True or False?
• Partial seizures have no discernible origin in the brain.
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
• False
• Rationale: Generalized seizures have no discernible origin
in the brain. Partial seizures begin in a specific area of
the brain.
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Seizure Classifications (cont.)
• Generalized seizures
– Bilateral
– Symmetric
– No discernible point of origin in the brain
– Most common type
• Tonic–clonic
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Seizure Classifications (cont.)
• Generalized seizures (cont.)
– Absence seizure
• Alteration in consciousness that lasts only a few
seconds
– Myoclonic
• Contraction of muscle or group of muscles
– Akinetic
• Absence of movement
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Seizure Classifications (cont.)
• Status epilepticus
– Life-threatening emergency
– Characteristics include
• Generalized tonic–clonic convulsions lasting for
several minutes
• Generalized tonic–clonic convulsions occurring at
close intervals during which consciousness is not
regained
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Seizure Classifications (cont.)
• Status epilepticus (cont.)
– Characteristics include (cont.)
• Hypotension, hypoxia, and cardiac dysrhythmias
• High risk of permanent brain damage and death
• Unless prompt, appropriate treatment is
instituted
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Seizure Classifications (cont.)
• Status epilepticus (cont.)
– Causes
• Abruptly stopping AEDs in diagnosed seizure
disorders
• Brain trauma or tumors
• Systemic or CNS infections
• Alcohol withdrawal, drug overdose
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Generalized Characteristics of
Antiseizure Drugs
• Usually control seizure activity
• Do not cure underlying disorder
• Difficulties
– Trials of different drugs
– Monotherapy versus combination therapy
– Titrating dosage
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Generalized Characteristics of
Antiseizure Drugs (cont.)
• Difficulties (cont.)
– Lack of seizure control during drug selection and
titration
– Social stigma
– Adverse medication effects
• Often leading to poor compliance
– Undesirable drug interactions
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Phenobarbital
• Depresses the CNS by inhibiting the conduction of
impulses in the ascending reticular activating system, thus
depressing the cerebral cortex and cerebellar function
• Used as a sedative and antiepileptic agent in the
treatment of generalized tonic–clonic and partial seizures
• Parenteral form is used to control acute seizures.
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Adverse Effects
• CNS depression
• Cognitive impairment with sedation
• Somnolence, agitation, confusion, vertigo, and
nightmares
• Stevens-Johnson syndrome
• Black box warning
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Benzodiazepines
• Used as antidepressants, antiepileptics, or skeletal
muscle relaxants
• Used for treatment of severe recurrent convulsive
seizures and status epilepticus
• Contraindications include acute narrow-angle glaucoma,
shock, coma, acute alcohol intoxication, and pregnancy
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Neurontin
• Used in treatment of partial seizures
• It has the ability to inhibit postsynaptic responses and
block post-tetanic potentiation.
• Patient teaching
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Dilantin
• Oldest and most widely used antiepileptic
• Stabilizes the neuronal membrane by delaying the influx
of sodium ions into the neurons and preventing the
excitability caused by excessive stimulation
• Used to control tonic–clonic seizures, psychomotor
seizures, and nonepileptic seizures
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Adverse Effects
• Ataxia, drowsiness, lethargy
• Nausea and vomiting
• Gingival hyperplasia
• Increased risk of osteoporosis
• Patient teaching
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Monitoring Antiepileptic Drug Therapy
• Periodic measurement of serum drug levels
– Document blood levels and connections with
• Drug dosages, seizure control, or adverse drug
effects
– Assess
• Therapeutic failures
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Monitoring Antiepileptic Drug Therapy
(cont.)
– Assess (cont.)
• Drug malabsorption
• Patient noncompliance
– Guide dosage adjustments.
– Evaluate possible drug-related adverse effects.
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Drug Therapy Failure
• Causes
– Noncompliance, inadequate drug dosage
– Incorrect diagnosis or medication for seizure type
– Too frequent changes or premature withdrawal
– Drug overdoses, use of alcohol or recreational drugs
– Severe electrolyte imbalance
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Use in Special Populations
• Children
• Older adults
• Patients with renal impairment
• Patients with hepatic impairment
• Patients with critical illness
• Home care
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Definitions
• Skeletal muscle relaxants are used to decrease muscle
spasms or spasticity that occurs within neurologic and
musculoskeletal disorders.
– Muscle spasm: sudden, involuntary, painful muscle
contraction
• May be clonic or tonic
– Spasticity: increased muscle tone or contraction and
stiff, awkward movements
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
• Is the following statement True or False?
• Spasticity is a sudden, involuntary, painful muscle
contraction.
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
• False
• Rationale: Spasticity is increased muscle tone or
contraction and stiff, awkward movements. Muscle
spasm is a sudden, involuntary, painful muscle
contraction.
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General Characteristics of Skeletal Muscle
Relaxants
• Mechanism of action
– General depression of the CNS
• Indications for use
– Primarily as adjuncts to other treatments
• Physical therapy
– Spastic disorders
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General Characteristics of Skeletal Muscle
Relaxants (cont.)
• Contraindications for use
– Impaired renal or hepatic function
– Respiratory depression
– Patients who must be alert for activities of daily living
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Principles of Skeletal Muscle Relaxant
Therapy
• Goal: relieve pain, muscle spasm, and muscle spasticity
without impairing the ability to perform self-care
activities
• Drug selection
– Medication used depends mainly on the disorder
being treated.
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Principles of Skeletal Muscle Relaxant
Therapy (cont.)
• Use in special populations
– Children
– Older adults
– Impaired renal or hepatic function
– Home care
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