40: Antiparkinson's Drugs Flashcards Preview

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Flashcards in 40: Antiparkinson's Drugs Deck (32):
1

loss of dopaminergic neurons in the basal ganglia leads to altered movement control

parkinson's and huntington's disease

2

what prtns accumulate with parkinson's disease?

intracytoplasmic aggregates
alpha-synuclein

3

"lewy bodies"

indicator of parkinson's disease

4

pathology of parkinsons

progressive loss of DA containing neurons in the basal ganglia, eventually leads to total loss of motor function and muscle control

5

what are some "non-motor" effects of PD?

other brain structures are also affected (brainstem, hippocampus, and cerebral cortex)

cognitive decline
affective disorders
sleep disorders
sensory complaints or pain

6

4 cardinal symptoms of PD

1. bradykinesia
2. muscular rigidity
3. resting tremor
4. postural instability

7

degeneration of ____ neurons in ________ (part of basal ganglia) that project to ______ (putamen and caudate nucleus)

dopaminergic
substantia nigra
striatrum

8

decreasing DA --> increasing __

Ach

loss of dopaminergic input into striatum is also accompained by increased activity of the cholinergic pathways in the basal ganglia

9

alpha synuclein accumulation, formation of Lewy bodies, and increased production of free radicals --->

interference with neuronal function that leads to neuronal atrophy and death

10

5 treatment strategies for PD

1. DA replacement
2. DA receptor agonists
3. L-DOPA degradation inhibitors
4. increase in DA release
5. Anticholinergic agents

11

most common drug used to treat PD

L-DOPA (levodopa)

can't give straight DA because it does not cross BBB

12

Why use carbidopa and L-DOPA together?

carbidopa is an inhibitor of DA decarboxylase in the periphery --> inhibits premature breakdown of levodopa in the periphery and therfore increases fraction L-DOPA that actually reaches the brain

13

adverse effects of L-DOPA

-dyskinesia (involuntary movements similar to tics and tremors)
- response fluctuations
-GI disturbance
-Postural hypotension and Tachycardia
- Behavioral disturbances

14

"drug holiday"

stop taking L-DOPA for a period of time to improve response fluctuation problems

15

What drugs interact with L-DOPA?

**pyridoxine* (vitamin B6)
- will enhance peripheral conversion of LDOPA

also interacts iwth MAOai, antipsychotics, prtn rich meals, and anticholinergics

16

name three DA receptor agonists

pramipexole
ropinirole
apomorphine

17

rescue treatment for LDOPA induced dyskinesia

apomorphine

subQ route for temporary relief

18

clinical uses for DA receptor agonists

-first line or initial therapy for PD; effective as monotherapy for mild parkinsonism

19

associated with lower incidence of response fluctuations and dyskinesias

DA receptor agonists

LDOPA has worse side effects

DA receptor agonists can be helpful in pts with advanced PD that allows for reduction in LDOPA dose and improvement of response fluctuations

20

interesting adverse effect of DA receptor agonists

potential problems with impulse control disorders

GI (anorexia, nausea, vomiting, constipation) are more common adverse effects

21

MOA rasagiline and selegiline

MAO-B inhibitors --> DA degradation blockers


inhibits MAO-B selectively at lower doses and decreases breakdown of DA

22

clinical use MAO-B inhibitors

adjunctive to levodopa primarily in pts with declining or fluctuating response to levodopa

23

adverse effects Rasagiline and Selegiline

GI upset
Serotonin syndrome

does not display wine and cheese interaction

24

MOA entacapone and tolcapone

COMT inhibitors

25

preferred COMTi for PD

entacapone

because it has not been associated with hepatotoxicity (tolcapone)

26

what drug causes increased DA release?

amantadine

antiviral agent that has antiparkinsonism properties discovered by chance

short duration of action and effectiveness (12mo)

27

observe blotchy reddened pattern on legs on PD patient. what drug might be causing this and what is it called?

livedo reticularis caused by amantadine

clears w/i 1 mo after stoppage

28

MOA benztropine and trihexyphenidly

antagonist at muscarinic receptors in basal ganglia

29

what are the clinical effects of anticholinergic agents for PD?

reduces tremor and rigidity -- little effect on bradykinesia

30

what are the adverse effects of anticholinergic agents?

drying up - the opposite of SLUDGE

urinary retention
dry mouth
mydriasis and blurred vision
constipation
sedation
confusion
toxic psychosis

31

advanced PD and drugs aren't working...

ablative surgical procedures or high-frequency deep brain stimulation may provide beneficial effects or transplantation of dopaminergic fetal tissue

32

pt is receiving bilateral stimulation of the subthalamic nucleus -- should they also be taking meds?

nope

actually do better with this treatment if off meds