1 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Chapter 23 DRUGS FOR NEUROLOGIC DISORDERS: PARKINSONISM AND ALZHEIMER’S DISEASE

2 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Parkinsonism  Pathophysiology  Chronic neurologic disorder  Degeneration of dopaminergic neurons  Imbalance of the neurotransmitters Less dopamine

3 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Parkinsonism (cont’d)  Characteristics  Tremors of head and neck  Rigidity (increased muscle tone)  Bradykinesia (slow movement)  Postural changes Head and chest thrown forward  Shuffling walk  Lack of facial expression  Pill-rolling motion of hands

4 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Parkinsonism (cont’d)  Treatment regimen  Anticholinergics Block cholinergic receptors  Dopaminergics Convert to dopamine  Dopamine agonists Stimulate dopamine receptors  MAO-B inhibitors Inhibit MAO-B enzyme that interferes with dopamine  COMT inhibitors Inhibit COMT enzyme that inactivates dopamine

5 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antiparkinsonism Drugs  Anticholinergics  Parasympatholytic Benztropine (Cogentin) Trihexyphenidyl HCl (Artane)  Action: inhibit release of acetylcholine Decrease tremors and rigidity

6 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antiparkinsonism Drugs (cont’d)  Anticholinergics  Nursing Interventions Monitor vital signs for increased P. Monitor urine output for early detection of urinary retention. Increase fluid intake, fiber, and exercise to avoid constipation. Observe for involuntary movements. Advise client to avoid alcohol, cigarettes, caffeine, and aspirin to decrease gastric acidity. Encourage client to relieve dry mouth with ice chips, hard candy, or sugarless chewing gum. Suggest use of sunglasses for photophobia.

7 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antiparkinsonism Drugs (cont’d)  Dopaminergics  Carbidopa-levodopa (Sinemet)  Action: converted to dopamine Increases mobility  Side effects Fatigue, insomnia Dry mouth Blurred vision Orthostatic hypotension, palpitations, dysrhythmias Urinary retention Nausea, vomiting Dyskinesia, psychosis, severe depression

8 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Dopaminergics  Carbidopa-levodopa (Sinemet)  Drug interactions Decrease levodopa effect with:  Anticholinergics  Phenytoin  Tricyclic antidepressants  MAO inhibitors  Benzodiazepines  Phenothiazines  Vitamin B 6

9 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Dopaminergics (cont’d)  Carbidopa-levodopa  Function  Advantages A, When levodopa is used alone, only 1% reaches the brain because 99% converts to dopamine while in the peripheral nervous system. B, By combining carbidopa with levodopa, carbidopa can inhibit the enzyme decarboxylase in the periphery, thereby allowing more levodopa to reach the brain.

10 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Dopamine Agonists  Amantadine (Symmetrel)  Also antiviral drug for influenza A  Action Stimulates dopamine receptors  Taken alone or in combination with levodopa or anticholinergic  Use Early treatment of parkinsonism as drug tolerance develops Improvement of symptoms

11 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antiparkinsonism Drugs (cont’d)  Nursing interventions  Monitor for orthostatic hypotension.  Administer drug with low-protein foods.  Avoid vitamin B 6, alcohol, other depressants.  Do not abruptly discontinue.  Warn of harmless brown discoloration of urine and sweat.  Assess for suicidal tendencies.  Assess symptom status and “on-off” phenomenon.  Monitor blood cell counts, liver and kidney function.

12 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Alzheimer’s Disease  Pathophysiology  Progressive, degenerative disease  Neuritic plaques form  Neurofibrillary tangles are in neurons  Cholinergic neurotransmitter abnormality

13 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Alzheimer’s Disease (cont’d)  Pathophysiology  Histologic changes Histologic changes in Alzheimer’s disease. A, Healthy neuron. B, Neuron affected by Alzheimer’s disease showing characteristic neuritic plaques and cellular neurofibrillary tangles.

14 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Alzheimer’s Disease (cont’d)  Characteristics  Loss of memory, logical thinking, judgment  Time disorientation  Personality changes  Hyperactivity  Tendency to wander  Inability to express oneself  Later hostility, paranoia

15 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Acetylcholinesterase Inhibitors  Donepril (Aricept)  Rivastigmine (Exelon)  Action  Allow more acetylcholine in neuron receptors  Increase cognitive function  Use  Mild to moderate Alzheimer’s disease

16 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Acetylcholinesterase Inhibitors (cont’d)  Side effects  Headache, dizziness  Depression  GI distress  Dehydration, dry mouth, constipation  Blurred vision  Insomnia  Hypertension, hypotension, dysrhythmias  Hepatotoxicity

17 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Acetylcholinesterase Inhibitors (cont’d)  Nursing interventions  Monitor vital signs.  Maintain consistency in care.  Monitor behavioral changes.  Safety Provide safety when wandering. Arise slowly to avoid dizziness.  Monitor for GI bleeding.  Inform family of support groups.

18 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Case Study A client who has parkinsonism is taking carbidopa/levodopa (Sinemet). Critical Thinking 1. What laboratory values may be altered in a client who is taking carbidopa/levodopa? 2. Compare the different actions of the drugs used to treat parkinsonism and reduce symptoms.

19 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Practice Question #1 Which comment to the nurse indicates more teaching is needed for a client taking carbidopa/levodopa? A.“I know I need to take this drug once a day.” B.“I know I shouldn’t stop taking this drug abruptly.” C.“I understand my urine may become dark and discolored.” D.“I know it may take a few weeks or months to control my symptoms.”

20 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Practice Question #1 (cont’d) Answer: A Rationale: A statement from the client such as “I know I need to take this drug once a day” indicates that more teaching is needed because carbidopa/levodopa has a short half-life and must be taken 3 or 4 times per day. The other answers are true.

21 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Practice Question #2 Which side effect/adverse effect of carbidopa/levodopa does the nurse realize is most important to monitor? A. Dysphagia B. Increased libido C. Agranulocytosis D. Urinary retention

22 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Practice Question #2 (cont’d) Answer: C Rationale: It is most important for the nurse to monitor the client taking carbidopa/ levodopa for agranulocytosis (decreased white blood cells), which is life-threatening. Dysphagia, increased libido, and urinary retention are not life threatening.