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27 Cards in this Set
- Front
- Back
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Causes of Parkinson's
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Degeneration of DA in Basal Ganaglia in the extrapyramidal tract.
Antipsychotic drugs. BG inhibits cholinergic neurons Ach increases. |
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Mechanism of Levadopa (l-dopa)
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Crosses BBB.
Converts to DA in brain by dopa decarboxylase (DDC) which restores DA/Ach balance. |
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Indications of Levadopa (l-dopa)
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-Best of available agents
-In US, levodopa is given only as a combination pack |
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Advantages of Levadopa (l-dopa)
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Improves movement velocity
-Reduces tremor and rigidity |
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Disadvantages of Levadopa (l-dopa)
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Due to formation of DA in periphery (nausea/vomiting, cardiac problems, OH)
-Dyskinesias (after 3 months to several years of therapy) -Behavorial changes (psychotic symptoms, depression) -Diminished response after 3-4 years of therapy -On-off and wearing-off phenomenon (associated with low levels of levadopa) - Unpredictable |
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Indications of Sinemet = Carbidopa + Levodopa
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- Carbidopa given in combination with levodopa
-Prevents conversion of levodopa to DA in the periphery (preserves more levodopa for conversion to DA in CNS, ↓ peripheral side effects, ↓ levodopa dose by 75-80%) |
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Mechanism of Sinemet = Carbidopa + Levodopa
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Peripheral DDC inhibitors. So less of the DA is lost in the perihpery.
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Advantages of Sinemet = Carbidopa + Levodopa
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Not lost as much in perihpery
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Disadvantages of Sinemet = Carbidopa + Levodopa
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Still have CNS side effects
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Mechanism of Ropinirole (Requip), Pergolide (Permax)
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Stimulates DA receptors, restores DA/Ach
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Indications of Ropinirole (Requip), Pergolide (Permax)
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Often used in combination.
Used for restless leg syndrome. |
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Advantages of Ropinirole (Requip), Pergolide (Permax)
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Improves movement velocity
-Reduces tremor and rigidity |
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Disadvantages of Ropinirole (Requip), Pergolide (Permax)
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Peripheral and behavioral effects similar to levadopa
Due to formation of DA in periphery (nausea/vomiting, cardiac problems, OH) -Dyskinesias (after 3 months to several years of therapy) -Behavorial changes (psychotic symptoms, depression) -Diminished response after 3-4 years of therapy -On-off and wearing-off phenomenon (associated with low levels of levadopa) - Unpredictable |
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Mechanism of Benztropine (Cogentin)
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Anticholinergic Drug.
Inhibits choinergic activity in the corpus striatum and restores the DA/Ach balance. |
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Indications of Benztropine (Cogentin)
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Often used in combination
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Advantages of Benztropine (Cogentin)
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Effective for antipsychotic drugs that are induced Parkinson's
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Disadvantages of Benztropine (Cogentin)
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Anticholinergic side effects such as memory failure, decrease in secretions, and constipation.
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Mechanism of Amantadine (Symmetrel)
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Inhibits NMDA receptor: may restrict neuronal patterns
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Disadvantages of Amantadine (Symmetrel)
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Patches of skin discoloration
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Mechanism of Selegiline (Deprenyl, Eldepryl)
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Inhibits MAOB and thus DA breakdown
-↑ DA at synapse, restores DA/Ach balance -Enhances and prolongs levodopa effects (reduces peripheral metabolism) |
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Indications of Selegiline (Deprenyl, Eldepryl)
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In early stages, may slow disease progression
-In later stages, administered with levodopa, may reduce on-off wearing-off phenomena |
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Advantages of Selegiline (Deprenyl, Eldepryl)
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-Less drug and food intearactions than MAO antidepressant inhibitors
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Disadvantages of Selegiline (Deprenyl, Eldepryl)
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-At higher doses, loses specificity
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Mechanism of Selegiline (Deprenyl, Eldepryl)
COMT Inhibitors – Tolcapone (Tasmar), Entacapone (Comtan) |
Inhibit catechol-O-methyl-transferase
-↑ DA at synapse -Enhance and prolong levodopa effects |
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Indications of Selegiline (Deprenyl, Eldepryl)
COMT Inhibitors – Tolcapone (Tasmar), Entacapone (Comtan) |
Primarily in combination
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Advantages of Selegiline (Deprenyl, Eldepryl)
COMT Inhibitors – Tolcapone (Tasmar), Entacapone (Comtan) |
May reduce levadopa on-off
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Disadvantages of Selegiline (Deprenyl, Eldepryl)
COMT Inhibitors – Tolcapone (Tasmar), Entacapone (Comtan) |
Similar to levadopa
Due to formation of DA in periphery (nausea/vomiting, cardiac problems, OH) -Dyskinesias (after 3 months to several years of therapy) -Behavorial changes (psychotic symptoms, depression) -Diminished response after 3-4 years of therapy -On-off and wearing-off phenomenon (associated with low levels of levadopa) - Unpredictable |
