Pharmacology - Drug Tx of Parkinson's (Exam 3) Flashcards
Tremor at rest, postural instability, dysphagia, drooling, bradykinesia, may progress to akinesia
Dyskinesias
Chronic, idiopathic neurodegeneration of extrapyramidal system causing loss of control of movement
Parkinson’s Disease
Dementia, depression, impaired memory
Psychological disturbances of PD
Parkinson’s like symptoms:
Drug side effects
Component of other disorders (Shy-Drager syndrome)
Less responsive to drug therapy used for PD
Parkinsonism
Idiopathic loss of nigrostriatal dopaminergic neurons
Parkinson’s Disease
Drug therapy increases _________ in striatum
dopamine
Levels of what neurotransmitter are reduced in PD?
Striatal dopamine
What are potential side effects, complications, and interactions of PD?
Facial movements
Hypotension
Nausea
Opioid interactions
Catecholamine interactions
Describe the neuropathophysiology of PD (4 things)
- Loss of cell bodies in substantia nigra
- Genetic risk factors
- Antipsychotic drugs/environmental agents can cause parkinson-like syndrome
- MPTP (dopamine neurotoxin) causes parkinson-like syndrome
What is involved in the extrapyramidal system? (4 things)
- Nigrostriatal dopaminergic pathway
- Striatal cholinergic neurons
- GABAergic neurons
- Balance between dopaminergic and cholinergic activity (controls voluntary movement)
Inhibitory neurons innervating striatum
Nigrostriatal dopaminergic pathway
What is the goal of drug therapy for PD?
Raise dopamine levels
What is the goal of drug therapy for parkinsonism?
Lower ACh levels
Disease where there is a defect in GABAergic neurons
Huntington’s Disease
Genetic disease caused by triplet nucleotide repeat
Huntington’s Disease
Mechanism of Levodopa (L-dopa)
Converted to dopamine in striatum
T/F dopamine crosses the blood brain barrier
FALSE
T/F DOPA crosses the blood brain barrier
True
Which enzyme converts Tyrosine to Dihydroxyphenylalanine (DOPA)?
Tyrosine hydroxylase
Which enzyme converts Dihydroxyphenylalanine (DOPA) to dopamine?
Aromatic L-amino acid decarboxylase
What are the symptoms of peripheral toxicity of Levodopa?
GI: nausea, vomiting
Heart: postural hypotension, arrhythmia
What are the symptoms of CNS toxicity of Levodopa?
Neurological: dyskinesias (abnormal mouth movements, tongue thrusting, chewing motions)
Behavioral: insomnia, anxiety, delirium, depression
Sympathomimetic drug (B agonist) + Levodopa
Cardiac stimulation
Pyridoxine (vitamin B6) + Levodopa
Decreased efficacy of Levodopa
Antipsychotic drugs + Levodopa
Decreased efficacy of Levodopa
Monoamine oxidase inhibitors (MAOIs) + Levodopa
Hypertensive crisis
What are the 2 fluctuations in therapeutic response of Levodopa?
- “Wearing off” phenomenon
- “On-off” phenomenon
What are the components of the “wearing off” phenomenon of Levodopa?
Related to timing
Nigrostriatal tract degeneration
What are the components of the “on-off” phenomenon of Levodopa?
Alterations in drug availability NOT related to timing
What is Sinemet a mix of?
Levodopa + Carbidopa