Anti-Parkinson Flashcards
concept: Why does increasing DOPA make sense
@ normal physiological context DOPA levels are negligilbe. since rate limiting step is tyrosine OHase above DOPA production, if you load up on substrate you can increased DA = good to go for parkinson hurrah.
Goal of therapy for Parkinson
want to decrease GABA – normally DA stimulates GABA neurons and Ach decreased GABA – so goal is to get more DA and less Ach so that GABA activity is increased
What happens when levidopa is decarboxylated in the periphery ie symptoms
nausea
vomiting
cardiac arrhtymias
hypotension
Why does food slow the appearance of levidopa in the plasma?
amino acids compete with absorption from gut and transport from blood to brain
Wearing Off Phenomenon VRS On-Off Phenomenon
wearing off - fluctuations due to timing of levodopa administration
On-off phenomenon - fluctautions not due to timing of levodopa administration
How to treat the Offs of the ON Off phenomenon
give apomorphine
What vitamin is contraindicated with levodopa and why
vitamin B6 because is a cofactor for DOPA decarboxylase and increases peripheral metabolism of levodopa
Why cant you use levodopa with a nonspecific MAO inhibitor
hypertensive crisis
What type of meds and patients shouldnt be given levodopa
healthy people and ppl on antipsychotics or with mental disturbances
What eye probelms contraindicated levodopa
angle closure glaucoma
What heart problems are significinat?
can cause arrhtymias in cardiac patients
Name the ergot D2 agonist
Bromocriptine
Name the nonergot D2 agonists
Pramipexole
Ropinirole (pin role = parkinson side effect ;))
Rotigotine
Which nonergo D2 agonist is available only transdermal
Rotigotine`
Ergot side effects please :) only the bolded ones
Bromocriptine: pulmonary infiltrates
plueral and retroperitoneal fibrosis
erythromelalgia (bouts of pain cuased by temperature, turns red, usually hands and feet)
Nonergot side effects bolded please
Pramipexole
Ropinirole (Ro-pin roll)
Rotigotine
SOMNOLENCE
~*~Contraindications and be careful pateints for DA agonists
psychotic illness
recent mi (causes arrhythmias)
periperal vascular disease (erytrmelalgia and vasospasm @ periphery)
puptic ulceration (makes em bleed)
Who cares about Apomorphine and why
rescue for OFF episodes of akinesia
emetogenic so give an antiemtic first
other effects i dont have time for- not bolded
Which MAO i are used as adjuncts for levodopa treatment?
selegiline - deprenyl
and
(new one, not listed in antidepressant lec) =
Rasagiline
GILINES
What is a concern about the metabolism of selegilin
metabolized to metamphetamine and amphetamine so can cause insomnia if take late in the day
Justify the use of Tolcapone (gangster) and Entacapone
Tolcapone and Entacapone inhibit COMT –> thus levodopa is not metabolized to 3-o-methyl dopa so there is no compeition for uptake of levodopa to the BBB or the intestine; when you use carbidopa it causes increase shunting of levodopa to its metabolite
Describe site of action of tolcapone and entacapone
tolcapone - in bbb and intestine
entacapone - periphery (enterocytes ie enta @ gut)
~*~A/se of tolcapone
fulminating hepatic necrosis; entacapone doesnt cause this so preferred.
~*~Antiviral with antiparkinsonism effects?
Amantadine
