Chapter 52 Drug Therapy for Seizure Disorders and Spasticity

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Chapter 52

Drug Therapy for Seizure

Disorders and Spasticity


Seizure DisordersSeizure 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


QuestionQuestion

• Is the following statement True or False?

• Seizure and convulsion are different terms for the same disorder.


AnswerAnswer

• 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.


EpilepsyEpilepsy

• 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


Epilepsy (cont.)Epilepsy (cont.)

• Classifications

– Idiopathic

– Attributable to secondary cause

• Developmental defects

• Metabolic disease, birth injury

• Fever, acquired neurologic disorder

• Alcohol or other drug effects


QuestionQuestion


• Epilepsy can be classified as either idiopathic or attributable to secondary causes.


AnswerAnswer

• True

• Rationale: Epilepsy can be classified as either idiopathic or attributable to secondary causes.


Seizure ClassificationsSeizure Classifications

• Partial seizures

– Begin in a specific area of the brain

– Often indicate a localized brain lesion

• Birth injury

• Trauma

• Stroke

• Tumor


Seizure Classifications (cont.)Seizure Classifications (cont.)

• Partial seizures (cont.)

– Symptoms range from

• Simple motor and sensory effects

– To

• More complex abnormal movements and bizarre behavior




– Movements are usually

• Automatic

• Repetitive

• Inappropriate to the situation

• Chewing, swallowing

• Aversive movements




– Simple partial seizures

• Consciousness not impaired

– Complex partial seizures

• Level of consciousness is decreased.


QuestionQuestion


• Partial seizures have no discernible origin in the brain.


AnswerAnswer

• False

• Rationale: Generalized seizures have no discernible origin in the brain. Partial seizures begin in a specific area of the brain.



• Generalized seizures

– Bilateral

– Symmetric

– No discernible point of origin in the brain

– Most common type

• Tonic–clonic


Seizure Classifications (cont.)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



• 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



• 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



• Status epilepticus (cont.)

– Causes

• Abruptly stopping AEDs in diagnosed seizure disorders

• Brain trauma or tumors

• Systemic or CNS infections

• Alcohol withdrawal, drug overdose


Generalized Characteristics of Antiseizure DrugsGeneralized Characteristics of Antiseizure Drugs

• Usually control seizure activity

• Do not cure underlying disorder

• Difficulties

– Trials of different drugs

– Monotherapy versus combination therapy

– Titrating dosage


Generalized Characteristics of Antiseizure Drugs (cont.)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


PhenobarbitalPhenobarbital

• 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.


Adverse Effects Adverse Effects

• CNS depression

• Cognitive impairment with sedation

• Somnolence, agitation, confusion, vertigo, and nightmares

• Stevens-Johnson syndrome

• Black box warning


Benzodiazepines 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


NeurontinNeurontin

• Used in treatment of partial seizures

• It has the ability to inhibit postsynaptic responses and block post-tetanic potentiation.

• Patient teaching


DilantinDilantin

• 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


Adverse Effects Adverse Effects

• Ataxia, drowsiness, lethargy

• Nausea and vomiting

• Gingival hyperplasia

• Increased risk of osteoporosis

• Patient teaching


Monitoring Antiepileptic Drug Therapy 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


Monitoring Antiepileptic Drug Therapy (cont.)Monitoring Antiepileptic Drug Therapy (cont.)

– Assess (cont.)

• Drug malabsorption

• Patient noncompliance

– Guide dosage adjustments.

– Evaluate possible drug-related adverse effects.


Drug Therapy FailureDrug 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


Use in Special PopulationsUse in Special Populations

• Children

• Older adults

• Patients with renal impairment

• Patients with hepatic impairment

• Patients with critical illness

• Home care


DefinitionsDefinitions

• 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


QuestionQuestion


• Spasticity is a sudden, involuntary, painful muscle contraction.


AnswerAnswer

• False

• Rationale: Spasticity is increased muscle tone or contraction and stiff, awkward movements. Muscle spasm is a sudden, involuntary, painful muscle contraction.


General Characteristics of Skeletal Muscle RelaxantsGeneral 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


General Characteristics of Skeletal Muscle Relaxants (cont.)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


Principles of Skeletal Muscle Relaxant TherapyPrinciples 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.


Principles of Skeletal Muscle Relaxant Therapy (cont.)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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Chapter 52 Drug Therapy for Seizure Disorders and Spasticity