4a: Parkinson's

Question 1

purpose of parkinson’s medications

Answer 1

normalize dopamine activity in the basal ganglia

Question 2

mechanism of Levodopa

Answer 2

this can cross the blood-brain barrier and is transformed into dopamine by an enzyme, although a lot of it gets transformed in the periphery before it gets to the brain

Question 3

what happens when Levodopa is converted to dopamine in the periphery?

Answer 3

this causes GI and cardiovascular side effects, and does not allow sufficient dopamine to reach the brain

Question 4

what is Carbidopa’s effect on Levodopa?

Answer 4

prevents Levodopa from being metabolized in the periphery, thus allowing more dopamine to reach the brain, and allows a smaller dosage of Levodopa to be administered

Question 5

Sinemet

Answer 5

combination of Levodopa and Carbidopa

Question 6

side effects of Levodopa

Answer 6

nausea, vomiting, cardiac problems (arrhythmias, orthostatic hypotension), dyskinesias, behavioral changes (psychosis, depression, anxiety, confusion)

Question 7

changes to side effects with Levodopa and Carbidopa are taken together

Answer 7

decreased GI and cardiac symptoms, but exacerbation of psychotic and behavioral symptoms

Question 8

3 main responses to Levodopa

Answer 8

end of dose akinesia, on-off phenomenon, freezing

Question 9

end-of-dose akinesia

Answer 9

parkinson’s drug effectiveness wears off before the next dose, can be resolved by adjusting the timing and/or quantity

Question 10

on-off phenomenon

Answer 10

decreasing dopamine levels which occurs suddenly and spontaneously resulting in worse parkinson’s symptoms, can occur repeatedly throughout the day

Question 11

freezing

Answer 11

patients stop walking and appear to be frozen in the upright position

Question 12

drug holiday

Answer 12

when parkinson’s drugs are no longer effective or side effects become too severe, patients can be gradually reduced from all anti-parkinson medication for days or weeks while being supervised (goal of recovering from tolerance or toxicity)

Question 13

greatest risks with drug holidays

Answer 13

fall risk, severe immobility that leads to DVTs, PEs, pneumonia

Question 14

other Parkinson’s meds

Answer 14

anticholinergic drugs, amantadine, MAOB inhibitors, COMT inhibitors

Question 15

implications of drug interactions with Sinemet

Answer 15

has a variety of side effects based on drugs taken with it; need to know all other medications to prevent/limit side effects

Question 16

rehab implications for Parkinson’s medications

Answer 16

• coordinate therapy at peak time of meds (1 hr after Levodopa)
• if on drug holiday, goal is to maintain mobility
• monitor BP closely (most PD meds cause orthostatic hypotension)
• work on balance, gait training, and strengthening

Question 17

Levodopa and meals

Answer 17

• high protein foods will delay the response of Levodopa
• elderly patients: 1 hour after breakfast dose is best time for therapy