Comprehensive Overview of Parkinson's Disease and Pharmacological Treatments

What is Parkinson's disease?

- degeneration of dopaminergic neurons in substantia nigra

- dec dopamine results in inc ACH

What are Parkinson's disease s/s?

- rigidity

- resting tremor

- bradykinesia

- postural instability

What is levodopa therapy used for?

- inc dopamine content in basal ganglia

- direct administration of dopamine ineffective because of blood-brain barrier

- must use L-DOPA

What is used together w L-DOPA?

carbidopa: prevents premature conversion of L-DOPA

Oral administration of dopamine is ineffective because...

dopamine is unable to pass from the blood stream to the brain

What are side effects of L-DOPA therapy?

- GI irritation

- hypotension

- psychiatric/behavioral effects

- dyskinesias

- "freezing" of gait

What is end-of-dose akinesia?

- wearing off or fading effect of levodopa therapy

- dec response toward end of dose cycle

- responses fluctuate within dose cycle

When is inhaled L-DOPA used?

to treat "off" episodes

What happens w long term use of L-DOPA therapy?

- benefits may be lost (after 4-5 years)

- dyskinesias become intolerable

- disease progresses and causes changes in the brain

What are other types of antiparkinson drugs?

- dopamine agonists (cross BBB)

- COMT inhibitors (inc L-DOPA in brain)

- anticholinergic agents (dec ACH)

- MAO-B inhibitors (prolong dopamine effects in brain)

- amantadine (dec influence of excitatory amino acids)

What are side effects of the other antiparkinson drugs?

- dopamine agonists: hallucinations, postural hypotension

- COMT inhibitors: OH, inc dyskinesia, diarrhea

- anticholinergic agents: anticholingeric effects

- MAO-B inhibitors: no major concerns

- amantadine: OH, psychotropic effects, skin discoloration

What are rehab concerns w antiparkinson drugs?

- recognize synergist effects of rehab and drug therapy

- coordinate rehab & drug therapy: PT 30-60 min after meds