PD - Current Therapies Flashcards
What are the aims of the current PD therapies?
Increase endogenous DA
Mimic DA
Prevent DA breakdown
Antagonise cholinergic action
What is levodopa?
A precursor of DA which crosses the BBB to be converted to DA
What is levodopa given in combination with?
Carbidopa (a decarboxylase inhibitor)
Why the levodopa given with this other drug?
To minimise its conversion to DA outwith the brain
Where is levodopa absorbed from?
The small intestine
How is levodopa absorbed?
Through active transport
What is the plasma half life of levodopa?
Approx 2 hours
Why does levodopa effectiveness decrease over time?
Natural progression of disease leads to receptor downregulation
What are the acute adverse effects of levodopa?
Nausea
Anorexia
Hypotension
SZ symptoms (bc increasing DA)
What are the long term adverse effects of levodopa?
Dyskinesia (within 2 years)
Fluctuations in clinical state
How could the fluctuations a/w levodopa be improved?
Give continuous levodopa
But this is impractical so smaller doses close together it the realistic approach
What is Selegiline?
MAO-B inhibitor
How does Selegiline work?
Monoamine oxidase B metabolises DA
it inhibits this and then increases the amount of DA kicking about
What are the peripheral side effects of Selegiline?
None
bc its selective
Foods containing which compound should be avoided whilst on MOA-B inhibitors?
Tyrosine
