Theory - Parkinsons 03 Flashcards
Where is MAO-A found and what does it metabolize?
Liver and brain
Metabolizes norepinephrine, dopamine, serotonin
Where is MAO-B found and what does it metabolize?
Brain only
Metabolizes dopamine
Which agent is the most effective against all four symptoms of Parkinson’s?
Levodopa
What is the endocrine effect of levodopa?
Dopamine produced from levodopa inhibits prolactin release from the anterior pituitary gland so a side effect of levodopa is hypoprolactemia
What is dyskinesia?
Voluntary movements begin to occur even when they are not wanted
What is akinesia?
The patient loses the ability to initiate voluntary movements
Dyskinesias occur in approximately 80% of Parkinson’s patients treated for five years with what drug?
Levodopa
Chorea (a dancing movement) occurs more commonly in patients receiving what drug?
Levodopa combined with carbidopa
Is a drug holiday helpful in the management of the on off phenomenon?
No. They are no longer recommended.
What percent of levodopa actually reaches the dopamine neurons of the substantia nigra?
1% (80% destroyed in the gut, 30% in the liver)
When levodopa is combined with carbidopa what percentage of levodopa reaches the dopamine neurons of the substantia nigra?
About 10%
What are the three mechanisms of amantadine?
1 - increased release of dopamine
2 - mild anticholinergic activity
3 - block NMDA receptor
What drug must you give an anti-emetic along with but it cannot be a 5HT3 receptor antagonist?
Apomorphine
What is the trouble with MAO-A?
It causes the cheese affect (selective MAOB does not cause the cheese effect)
What is the trouble with MAO-B?
It metabolizes to amphetamine and methamphetamine
