Anticonvulsants and Antiparkinsonism Drugs

1. Anticonvulsants and Antiparkinsonism Drugs Chapter 5

2. Anticonvulsant Drugs • Prevent convulsions or seizure • Partial or focal seizure • Arise from a localized area in the brain and cause specific symptoms • Can spread to the entire brain and cause a generalized seizure • Generalized seizure • Absence • Myoclonic • Tonic-clonic

3. Psychomotor Seizures • Occur most often in children. • Aura may precede the event. • Most common motor symptom is drawing or jerking of the mouth and face.

4. Epilepsy • Permanent, recurrent seizure disorder

5. Actions of Anticonvulsants • Reduce the excitability of the neurons of the brain

6. Uses of Anticonvulsants • Used to control seizure activity, but often a patient will not respond well to one drug, and another drug or a combination will be tried • Dose adjustments often are needed to find the correct level of control

7. Adverse Reactions of Anticonvulsants • The most common adverse reaction is sedation. • Can range from drowsiness to somnolence • Agitation rather than sedation may occur in some patients. • Adverse reactions may be reduced or eliminated with therapy or a decrease in dose.

8. Adverse Reactions of Anticonvulsants • Benzodiazepines also can cause sedation • Adverse reactions can be dose dependent and include: • Anorexia • Constipation or diarrhea • A health care provider should be notified if: • Unusual bruising or bleeding • Fever • Sore throat • Rash • Mouth ulcers

9. Adverse Reactions of Anticonvulsants • Hydantoins (phenytoin) are the most commonly prescribed anticonvulsants, and adverse effects include: • Nystagmus • Ataxia • Slurred speech • Mental changes • Gingival hyperplasia • Blood dyscrasias

10. Adverse Reactions of Anticonvulsants • Succinimides often cause gastrointestinal symptoms • Other adverse reactions: • Mental confusion • Personality changes • Pruritus • Urticaria • Urinary frequency • Weight loss • Hematologic changes

11. Adverse Reactions of Anticonvulsants • Miscellaneous anticonvulsants • Lamotrigine – severe and potentially fatal rash

12. Contraindications, Precautions, and Interactions of Anticonvulsants • Care should be taken with barbiturate use in patients with liver, kidney, or neurologic disorders or pulmonary disease. • Barbiturates are used with caution in hyperactive children. • Barbiturates will have an additive effect if used with alcohol or other CNS depressants.

13. Contraindications, Precautions, and Interactions of Anticonvulsants • Care should be taken with benzodiazepine use in patients with psychoses, acute narrow angle glaucoma, liver or kidney disease, or neurologic disorders. • Benzodiazepines should be used with caution in elderly or debilitated patients. • Alcohol and other CNS depressants can also have an additive effect when used with benzodiazepine. • Benzodiazepines interact with a number of other medications.

14. Contraindications, Precautions, and Interactions of Anticonvulsants • Hydantoins are contraindicated in patients with: • Sinus bradycardia • Sinoatrial block • Second- and third-degree AV block • Adams-Stokes syndrome • Liver disease • Pregnancy and lactation

15. Contraindications, Precautions, and Interactions of Anticonvulsants • Hydantoins have an additive effect with alcohol and other CNS depressants. • Phenytoin should be used with caution in patients with: • Hypotension • Severe myocardial insufficiency • Hepatic impairment • Phenytoin interacts with many different drugs.

16. Contraindications, Precautions, and Interactions of Anticonvulsants • Succinimides are contraindicated in patients with bone marrow depression or hepatic or renal impairment and during lactation. • Additive effect with alcohol, antidepressants, and narcotics • Concurrent administration with other anticonvulsants may require a dosage adjustment.

17. Contraindications, Precautions, and Interactions of Anticonvulsants • Miscellaneous anticonvulsants are used cautiously in patients with: • Glaucoma or increased intraocular pressure • History of cardiac, renal, or liver dysfunction or psychiatric disorders • Carbamazepine • Contraindicated in patients with bone marrow suppression or hepatic or renal impairment • Interacts with several other drugs

18. Contraindications, Precautions, and Interactions of Anticonvulsants • Valproic acid • Contraindicated in patients with renal impairment • Oxcarbazepine • May exacerbate dementia • Lamotrigine • Interacts with valproic acid • Miscellaneous anticonvulsants have an additive effect when combined with CNS depressants and alcohol.

19. Patient Management Issues with Anticonvulsants • Dosage adjustments may be necessary during initial treatment. • Dosage adjustments are based on patient’s response and adverse reactions. • Medication must be taken as prescribed. • Do not omit or miss a dose. • Do not abruptly discontinue.

20. Educating the Patient and Family About Anticonvulsants • Family may be the first to witness seizures. • Keep a record of all seizures. • Anticonvulsants control, but do not cure, epilepsy. • Support groups may be available. • Safety concerns may need to be addressed, such as driving or working conditions.

21. Educating the Patient and Family About Anticonvulsants • Do not increase, decrease, or omit dose. • Blood levels may need to be monitored. • Do not abruptly discontinue. • These drugs may cause drowsiness or dizziness. • Avoid alcohol. • Carry identification indicating drug use and type of seizures. • Do not use other medications without consulting a health care provider.

22. Educating the Patient and Family About Anticonvulsants • Hydantoins • Brush and floss • Make regular dental appointments for oral examination and care • Take with food • Shake the suspension before use

23. Educating the Patient and Family About Anticonvulsants • Succinimides • Take with food or milk to avoid gastrointestinal upset.

24. Antiparkinsonism Drugs • Parkinson disease – “paralysis agitans” is a degenerative disorder of the central nervous system • Caused by a deficiency of dopamine and an excess of acetylcholine within the central nervous system

25. Actions of Dopaminergic Drugs • Affect the dopamine content of the brain • Dopamine is not effective when given orally since it does not cross the blood-brain barrier. • Levodopa will cross the blood-brain barrier and then converts to dopamine.

26. Uses of Dopaminergic Drugs • Treat signs and symptoms of parkinsonism • Levodopa is the gold standard. • Carbidopa is always given with levodopa. • Amantadine is less effective than levodopa but more effective than anticholinergics.

27. Adverse Reactions of Dopaminergic Drugs • Choreiform movements • Dystonic movements • Mental changes: • Depression • Psychotic episodes • Paranoia • Suicidal tendencies

28. Off–On Phenomenon • Patient may suddenly alternate between improved clinical status and loss of therapeutic effect • Associated with long-term levodopa treatment • “Drug holiday” may be needed

29. Contraindications, Precautions, and Interactions of Dopaminergic Drugs • Levodopa is contraindicated in patients with narrow-angle glaucoma and taking MAOIs. • Levodopa interacts with many different drugs.

30. Contraindications, Precautions, and Interactions of Dopaminergic Drugs • Levodopa is used cautiously in patients with: • Cardiovascular disease • Bronchial asthma • Emphysema • Peptic ulcer disease • Renal or hepatic disease • Psychosis • Lactating patients

31. Contraindications, Precautions, and Interactions of Dopaminergic Drugs • Selegiline is used cautiously in patients with psychosis, dementia, or excessive tremor. • Selegiline increases the effectiveness of levodopa when they are taken together. • Selegiline interacts with fluoxetine.

32. Contraindications, Precautions, and Interactions of Dopaminergic Drugs • Amantadine is used cautiously in patients with: • Seizure disorders • Hepatic disease • Psychosis • Cardiac disease • Renal disease • Amantadine interacts with numerous other drugs.

33. Actions and Uses of Anticholinergic Drugs • Inhibit acetylcholine in the CNS • Used as adjunctive therapy in all forms of parkinsonism • Control drug-induced extrapyramidal disorders

34. Adverse Reactions of Anticholinergic Drugs • Dry mouth • Blurred vision • Dizziness • Mild nausea • Nervousness

35. Contraindications, Precautions, and Interactions of Anticholinergic Drugs • Contraindicated in patients with: • Glaucoma • Pyloric or duodenal obstruction • Peptic ulcers, prostatic hypertrophy • Achalasia • Myasthenia gravis • Megacolon

36. Contraindications, Precautions, and Interactions of Anticholinergic Drugs • Use with caution in: • Older adults • Cardiovascular disease (tachycardia, cardiac arrhythmias, hypertension, hypotension) • Urinary retention • Decreased liver or kidney function • Obstructive disease of the gastrointestinal tract

37. Actions and Uses of COMT Inhibitors • Catechol-O-methyltransferase (COMT) inhibitor • Thought to prolong the effect of levodopa by blocking the enzyme COMT, which would otherwise eliminate the dopamine • Used as an adjunct to levodopa/carbidopa • Easily crosses blood-brain barrier

38. Adverse Reactions of COMT Inhibitors • Disorientation and confusion • Light-headedness • Dizziness • Dyskinesias • Hyperkinesias • Nausea and vomiting • Hallucinations • Fever

39. Contraindications, Precautions, and Interactions of COMT Inhibitors • Contraindicated during lactation • Associated with liver damage and liver failure • Used with caution in patients with hypertension, hypotension, and decreased hepatic or renal function

40. Actions and Uses of Dopamine Receptor Agonists • Exact mechanism not understood • May mimic the effects of dopamine in the brain • Used for Parkinson disease

41. Adverse Reactions of Dopamine Receptor Agonists • Nausea • Dizziness • Postural hypotension • Hallucinations • Somnolence • Vomiting • Confusion • Visual disturbances • Abnormal involuntary movements • Headache

42. Contraindications, Precautions, and Interactions of Dopamine Receptor Agonists • Contraindicated in patients with severe ischemic heart disease or peripheral vascular disease • Use with caution in patients with: • Dyskinesia • Orthostatic hypotension • Hepatic or renal impairment • Cardiovascular disease • History of hallucinations or psychosis

43. Contraindications, Precautions, and Interactions of Dopamine Receptor Agonists • Increased risk of CNS depression • Increase the effects of levodopa when coadministered • Interact with ciprofloxacin and phenothiazines • Pramipexole interacts with a number of medication • Ropinirole interacts with estrogens

44. Patient Management Issues with Antiparkinsonism Drugs • History obtained from patient can be unreliable. • Baseline physical assessment needed. • Drug therapy needs careful monitoring. • Some patients communicate poorly. • Observe the patient for outward changes that may indicate adverse reactions. • Symptoms may be communicated through changes in posture and facial expression.

45. Educating the Patient and Family About Antiparkinsonism Drugs • The home environment must be examined to make it least likely to result in accidents or falls. • Medication should be taken as prescribed. • Sudden changes in behavior can indicate hallucinations, depression, or other psychotic episodes. • Observe the patient for adverse reactions.