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19 Cards in this Set
- Front
- Back
Parkinson's Disease is
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A progressive, chronic degenerative disorder involving brain regions that control all aspects of movement; results in degeneration of dopamine (DA) neurons in the SUBSTANTIA NIGRA
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Motor Symptoms of Parkinson's Disease
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1. Resting Tremor
2. Muscular Rigidity 3. Bradykinesia/akinesia- most disabling 4. Postural Instability 5. Gait and Posture- shuffling, decreased arm swing, neck and trunk rigid turning, Camtocormia 7. Dystonia 8. Speech and Swallowing Disturbances- hypophonia, festinating speech, drooling, decreased verbal fluency, dysphagia 9. Fatigue 10. Hypomimia 11. Impaired fine motor dexterity/coordination 12. Impaired gross motor coordination 13. Difficulty rolling in bed or rising frmo seat |
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Non-motor Symptoms of Parkinson's Disease
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1. Mood disturbances
2. Cognitive disturbances- slow reaction times, dementia, memory loss 3. Sleep disturbances- insomnia, somnolence (drowsiness) 4. Sensation disturbances- visual contrast, double vision, dizziness, pain, spatial reasoning 5. Autonomic disturbances- fainting due to OH, oily skin, urinary incontinence, constipation |
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Genetic Factors for Early Onset of Parkinson's Disease
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Defective genes mostly regulating alpha-synuclein and parkin
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Genetic Factors for Late Onset of Parkinson's Disease
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1. T-protein defect
2. Iron metabolism- have more iron deposits in the brain |
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Environmental Factors of Parkinson's Disease
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1. Toxins- excess production of free radicals damaging nerve cells
2. Infection- immune factors suggest a viral presence in Lewy bodies 3. Pesticides- high association of parkinsonism with rural areas |
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L-dopa (levodopa)
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1. Most reliable and effective oral treatment drug
2. Rapid onset of action, peak plasma levels 1-2 hours post dosing 3. Crosses the BBB via amino acid transporters 4. 90% peripheral metabolism 5. Metabolized by L-aromatic aa decarboxylase into DA in the presynaptic terminals of DA neurons in striatum 6. Must be combined with a peripherally acting dopadecarboxylase inhibitor that can't cross the BBB to prevent premature metabolism |
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Problems with L-dopa
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1. End-of-dose failure
2. On-off effect 3. Secondary L-dopa failure 4. Dyskinesias |
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L-dopa Peripheral Side Effects
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1. Nausea
2. Vomiting 3. Tachycardia 4. Orthostatic Hypotension 5. Cardiac arrhythmias 6. Anorexia |
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L-dopa Central Side Effects
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1. Hallucinations
2. Delusions 3. Motor fluctuations 4. Dyskinesias 5. Vivid dreams 6. Sleep disturbance |
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Dangerous Drug Combinations
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1. MAO inhibitors and L-dopa- results in life threatening hypertensive crisis and/or stroke
2. Adrenomimetic amines and L-dopa- used in asthma/emphysema treatment can lead to cardiac arrhythmias |
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Dopamine Receptor Agonists
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1. Bromocriptine (Parlodel)
2. Pergolide (Permax) 3. Pramipexole (Mirapex) 4. Ropinirol (Requip) |
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Dopamine Receptor Agonist Effects
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1. Stimulate the DA receptor sites directly
2. Long duration of activity, less effective than L-dopa 3. Used to delay initiation of L-dopa therapy 4. Side Effects: same as those for L-dopa with addition of somnolence, insomnia, and fatigue 5. Initially given at low dose that is increased as patient tolerance rises, therapeutic levels reached within a week |
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Amantadine
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1. Antiviral compound
2. Mech. of Action: unknown, thought to block uptake and enhance DA release 3. Works in early PD or in combination with L-dopa 4. Not effective in advanced PD when DA stores low 5. Side Effects: confusion, sedation, vivid dreams, hallucinations, OH, nausea/vomiting |
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COMT (Catechol-O-methyltransferase) Inhibitors
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1. Entacapone (Comtan)- short half life, taken with each dose of L-dopa/Carbidopa, ONLY inhibits peripheral COMT
2. Tolcapone (Tasmar)- longer duration of action, taken 3 times a day, inhibits BOTH peripheral and central COMT |
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COMT Inhibitors Effects
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1. Prevent metabolization of DA and L-dopa to inactive 3-O-methyl dopa
2. Prolongs effects of L-dopa, inhibits peripheral COMT increasing plasma half-life of L-dopa and fraction of L-dopa transported into the CNS 3. Helps with L-dopa "wearing off effect"- prolongs effectiveness of L-dopa 4. Side Effects: POSSIBLE FATAL HEPATOTOXICTY (tolcapone), confusion/ hallucinations, athoptosis |
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MAO-B (monoamine oxidase-B) Inhibitors: Selegiline
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1. Irreversible MAO-B Inhibitor
2. Inhibits DA metabolism (enhances endogenous DA levels) 3. Can delay L-dopa therapy/ reduce L-dopa doses 4. DONT administer with tricyclic antidepressants or selective serotonin uptake inhibitors--can be FATAL |
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The Anticholinergic Agents
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1. Benztropine
2. Procyclidine 3. Trihexyphenidyl 4. Diphenhydramine (Benadryl) |
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Anticholinergic Agent Effects
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1. Replaced belladona alkaloids (ex: atropine)
2. Inhibit Ach activity (trihexyphenidyl) 3. Block muscarinic receptors in striatum (benzotropine) 4. Effective for RELIEVING RIGIDITY and salivation (procyclidine) 5. Side Effects: constipation, urinary retention, confusion, hallucinations, etc 6. Benadryl (antihistamine diphenhydramine) has anticholinergic properties, APPEARS TO BLOCK DA REUPTAKE |