Chapter 52 Drug Therapy for Seizure Disorders and Spasticity

1. Chapter 52 Drug Therapy for Seizure Disorders and Spasticity

2. 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

3. Question • Is the following statement True or False? • Seizure and convulsion are different terms for the same disorder.

4. 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.

5. 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

6. Epilepsy (cont.) • Classifications • Idiopathic • Attributable to secondary cause • Developmental defects • Metabolic disease, birth injury • Fever, acquired neurologic disorder • Alcohol or other drug effects

7. Question • Is the following statement True or False? • Epilepsy can be classified as either idiopathic or attributable to secondary causes.

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

9. Seizure Classifications • Partial seizures • Begin in a specific area of the brain • Often indicate a localized brain lesion • Birth injury • Trauma • Stroke • Tumor

10. Seizure Classifications (cont.) • Partial seizures (cont.) • Symptoms range from • Simple motor and sensory effects • To • More complex abnormal movements and bizarre behavior

11. Seizure Classifications (cont.) • Partial seizures (cont.) • Movements are usually • Automatic • Repetitive • Inappropriate to the situation • Chewing, swallowing • Aversive movements

12. Seizure Classifications (cont.) • Partial seizures (cont.) • Simple partial seizures • Consciousness not impaired • Complex partial seizures • Level of consciousness is decreased.

13. Question • Is the following statement True or False? • Partial seizures have no discernible origin in the brain.

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

15. Seizure Classifications (cont.) • Generalized seizures • Bilateral • Symmetric • No discernible point of origin in the brain • Most common type • Tonic–clonic

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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.

23. Adverse Effects • CNS depression • Cognitive impairment with sedation • Somnolence, agitation, confusion, vertigo, and nightmares • Stevens-Johnson syndrome • Black box warning

24. 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

25. Neurontin • Used in treatment of partial seizures • It has the ability to inhibit postsynaptic responses and block post-tetanic potentiation. • Patient teaching

26. 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

27. Adverse Effects • Ataxia, drowsiness, lethargy • Nausea and vomiting • Gingival hyperplasia • Increased risk of osteoporosis • Patient teaching

28. 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

29. Monitoring Antiepileptic Drug Therapy (cont.) • Assess (cont.) • Drug malabsorption • Patient noncompliance • Guide dosage adjustments. • Evaluate possible drug-related adverse effects.

30. 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

31. Use in Special Populations • Children • Older adults • Patients with renal impairment • Patients with hepatic impairment • Patients with critical illness • Home care

32. 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

33. Question • Is the following statement True or False? • Spasticity is a sudden, involuntary, painful muscle contraction.

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

35. 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

36. 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

37. 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.

38. Principles of Skeletal Muscle Relaxant Therapy (cont.) • Use in special populations • Children • Older adults • Impaired renal or hepatic function • Home care