Pharmacological Management of Parkinson's Disease

Question 1

Common characteristics of Parkinson’s disease

Answer 1

Resting tremor
Bradykinesia
Rigidity
Postural Instability

Question 2

What causes Parkinson’s Disease?

Answer 2

Slow progressive degeneration of Dopamine-Secreting neurons in the Basal Ganglia.
Combination of genetic & environmental factors.
One of the most prevalent neurological disorders.

Question 3

What is the main purpose of Parkinson’s medication?

Answer 3

Normalize dopamine activity in the basal ganglia

Question 4

Genetic factors in Parkinson’s Disease

Answer 4

Mutated genes, formation of Lewy bodies in neuronal tissues, abnormal protein accumulation, & free radicals (unpaired electron)

Question 5

Primary drug used to treat Parkinson’s Disease

Answer 5

Levodopa

Question 6

Levodopa

Answer 6

Precursor to dopamine. Crosses BBB and is transformed into dopamine by an enzyme. Dose is slowly increased until symptoms occur; 2-3 doses per day.
Improves bradykinesia & rigidity

Question 7

What happens when Levodopa & Dopa Decarboxylase meet in the periphery?

Answer 7

Conversion within the periphery into dopamine, but it becomes useless because dopamine cannot cross the BBB

Question 8

Carbidopa

Answer 8

Peripheral decarboxylase inhibitor - Allows more levodopa to reach the brain before conversion into dopamine

Question 9

Levodopa + Carbidopa

Answer 9

Sinemet

Question 10

Side Effects of Levodopa

Answer 10

GI distress, cardiac problems, dyskinesias, behavioral changes

Question 11

Effects of prolonged Levodopa

Answer 11

Less effective over time (3-4 years)
Due to drug tolerance and progression of disease

Question 12

End of Dose Akinesia

Answer 12

Effectiveness of Levodopa wears off prior to next dose

Question 13

On-Off Phenomenon

Answer 13

Effectiveness of Levodopa spontaneously decreases resulting in worse Parkinsonian symptoms. Can occur repeatedly throughout the day

Question 14

Freezing

Answer 14

Patients stop walking and appear to be frozen due to fluctuating levodopa levels, variations in cerebral blood flow, or disruption in symmetric motor control

Question 15

Drug Holiday

Answer 15

Gradual removal of anti-Parkinson medication for 3 days - 3 weeks after meds begin losing effectiveness. Allows body to recover from drug toxicity or tolerance due to prolonged Levodopa use
50-70% of people benefit

Question 16

What is the greatest risk associated with Drug Holidays?

Answer 16

Severe immobility - Can lead to DVTs, PEs, pneumonia, and other impairments

Question 17

Dopamine Agonists

Answer 17

Mimic dopamine. Used with levodopa when it becomes less effective

Example: Pramipexole & Ropinirole

Question 18

Anticholinergic Drugs for Parkinsons

Answer 18

Alleviate ACh to assist in decreasing tremors and rigidity. Best when used with Levodopa. Often ACh levels are elevated when dopamine levels are low, which is why reducing these levels can help balance motor function

Question 19

Amantadine

Answer 19

Originally developed as an antiviral
Taken with Levodopa to reduce dyskinesias and other motor symptoms

Question 20

Side Effects of Amantadine

Answer 20

Orthostatic hypotension, CNS disturbances, & patches of skin discoloration

Question 21

Monoamine Oxidase B Inhibitors (MAO-B)

Answer 21

Inhibit the enzyme that breaks down dopamine - Results in dopamine having increased time to elicit its effects on the brain.
Can prolong taking Levodopa and slow the progression

Examples: Selegiline & Rasagiline

Question 22

Side effects of MAO-B Inhibitors

Answer 22

Dizziness, sedation, GI distress, & headache

Question 23

Catechol-O-Methyltransferase Inhibitors

Answer 23

Inhibit the COMT enzyme in order to prevent premature conversion of levodopa in the periphery. Allows more levodopa to reach the brain

Question 24

Levodopa + Carbidopa + COMT Inhibitor

Answer 24

Stalevo

Question 25

Drug Guidelines

Answer 25

Use dopamine agonists or MAO-B inhibitors initially to prolong need for Levodopa. Once motor symptoms worsen, then begin Levodopa - Combine it with other drugs as well (amantadine, anticholinergics, and COMT inhibitors)

Question 26

Rehab Implications for Parkinson’s Medication

Answer 26

Coordinate sessions at peak therapeutic time (1 hour after administration)
Maintain mobility in those on drug holiday
Monitor for orthostatic hypotension - Vitals!

Question 27

What should rehab focus on in Parkinsons?

Answer 27

Aggressive balance, gait training, & strengthening exercises