Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Is the following statement True or False? Seizure and convulsion are different terms for the same disorder.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Epilepsy (cont.) Classifications –Idiopathic –Attributable to secondary cause Developmental defects Metabolic disease, birth injury Fever, acquired neurologic disorder Alcohol or other drug effects

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Is the following statement True or False? Epilepsy can be classified as either idiopathic or attributable to secondary causes.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer True Rationale: Epilepsy can be classified as either idiopathic or attributable to secondary causes.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Seizure Classifications Partial seizures –Begin in a specific area of the brain –Often indicate a localized brain lesion Birth injury Trauma Stroke Tumor

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Seizure Classifications (cont.) Partial seizures (cont.) –Symptoms range from Simple motor and sensory effects –To More complex abnormal movements and bizarre behavior

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Seizure Classifications (cont.) Partial seizures (cont.) –Movements are usually Automatic Repetitive Inappropriate to the situation Chewing, swallowing Aversive movements

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Seizure Classifications (cont.) Partial seizures (cont.) –Simple partial seizures Consciousness not impaired –Complex partial seizures Level of consciousness is decreased.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Effects CNS depression Cognitive impairment with sedation Somnolence, agitation, confusion, vertigo, and nightmares Stevens-Johnson syndrome Black box warning

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Neurontin Used in treatment of partial seizures It has the ability to inhibit postsynaptic responses and block post-tetanic potentiation. Patient teaching

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Effects Ataxia, drowsiness, lethargy Nausea and vomiting Gingival hyperplasia Increased risk of osteoporosis Patient teaching

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Monitoring Antiepileptic Drug Therapy (cont.) –Assess (cont.) Drug malabsorption Patient noncompliance –Guide dosage adjustments. –Evaluate possible drug-related adverse effects.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Use in Special Populations Children Older adults Patients with renal impairment Patients with hepatic impairment Patients with critical illness Home care

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 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.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Principles of Skeletal Muscle Relaxant Therapy (cont.) Use in special populations –Children –Older adults –Impaired renal or hepatic function –Home care