Parkinsons Flashcards
What are the six cardinal signs of Parkinson’s Disease?
Feathered and tarred - TAR FLUFF (TAR FLF)
Tremors
Akinesia
Rigidity
Flexed-neck posture
Loss of postural reflexes
Freezing phenomenon
Why do we need to give the DA precursor L-DOPA rather than just dopamine?
Dopamine can’t cross the BBB.
Degeneration is what structure is responsible for Parkinsons?
The substantia nigra
What is the name of the projection from the substantia nigra to the basal ganglia?
The nigrostriatal pathway.
What structure does this DA/ACh balance actually effect directly?
The striatum (the receiving end of the nigrostriatal pathway).
What’s the pharmacokinetic con of levodopa?
Very low bioavailability due to MAOa (1-5%)
What enzyme catalyses the conversion of levodopa to dopamine?
DOPA decarboxylase.
What is given to deal with the piss poor bioavailability of levodopa?
Hint: it also ends in -dopa.
Hint: automobile auction.
CARBIDOPA. It’s a DOPA decarboxylase inhibitor that decreases peripheral metabolism of L-dopa so more can reach the brain.
What does carbidopa inhibit?
DOPA decarboxylase.
What’s the THM for levodopa efficacy?
It doesn’t treat the underlying disease (but does increase life expectancy). The responsiveness to L-DOPA therapy over time decreases, but we’re not sure if that’s due to disease deterioration or something like receptor downregulation.
Why do patients love carbidopa?
Reduces the prevalence and severity of initial side effects since less dosing is necessary.
Bonus: Carbidopa allows for about a 75% dose reduction of levodopa.
Levodopa has a pretty short duration of action. What are two characteristic side effects of levodopa?
DYSKINESIA - possibly a consequence of fluctuations in plasma concentration.
The ON-OFF phenomenon - cycle of exacerbation and resolution of symptoms.
What unwanted effects of levodopa will the patient have to deal with initially? (Less important for the subject than dyskinesia and on-off cycles).
THINNING-ish symptoms - anorexia, vomiting, nausea.
PSYCHOLOGICAL DISTURBANCES.
Carbidopa increases availability to the brain from X to Y.
1-5% to about 90%.
What are the non-ergot derived DA receptor agonists? Which DA receptors do they target?
PrimapeX lol
How would you help an imprisoned primapeX absail out of prison?
Pramipexol
Ropinirol (smuggle a rope in a roll)
D2 and D3