Chapter 69: Parkinson's Disease Flashcards
(56 cards)
Parkinson’s Disease occurs when
neurons in the substantia nigra die or become impaired
The cells in the substantia nigra produce which NT?
Dopamine - which allows smooth, coordinated function of body muscles and movement
What are the TRAP major symptoms of PD (due to less dopamine)
Tremor - when resting
Rigidity - in legs, arms, trunk and face (mask-like face)
Akinesia/bradykinesia - lack of/slow start in movement
Postural instability - imbalance, falls
What can be used to measure involuntary movements (i.e., tardive dyskinesias) from medications
The Abnormal Involuntary Movement Scale (AIMS)
Which drugs can worsen PD
Any drugs that block DA such as:
- Phenothiazines (e.g., prochlorperazine) used for psychosis, nausea, agitation
- Butyrophenones (e.g., haloperidol, droperidol) used for psychosis and behavior disorders or nausea
- FGA and SGA (e.g., risperidone at higher doses, paliperidone); lowest risk with quetiapine
- Metoclopramine, a renally-cleared drug that can accumulate in elderly patients
Even with high doses of PD drugs and various combinations, the disease will progress, including extended periods of “off time.” What does this mean
When symptoms of the disease worsen before the next dose of medication is due
Patients with PD have a high incidence of ___
depression. SSRIs or SNRIs are commonly used for treatment
Besides SSRIs and SNRIs, what other treatments can be used for depression in PD
TCAs (preferably secondary amines like desipramine and nortiptyline) and the DA agonist pramipexole
What is the preferred antipsychotic drug for PD psychosis & why
Quetiapine; low risk of movement disorders, but it can cause metabolic complications, including increased cholesterol and BG
What is the most effective treatment for PD
Levodopa (a prodrug of DA)
What medication is given with Levodopa & what is the combination called (brand name)
Carbidopa
Sinemet
Why is carbidopa given with levodopa
To prevent the peripheral metabolism of levodopa, which would destroy much of the drug before it crosses the BBB
Which drug class is used commonly for initial treatment in younger patients
DA agonists
Tremor-predominant disease in younger patients can be treated with a ______
Centrally-acting anticholinergic
Which drug is a precursor of dopamine
levodopa
What is the MOA of carbidopa
Inhibits dopa decarboxylate enzyme, preventing peripheral metabolism of levodopa
What is the starting dose for Sinemet IR
25/100 mg PO TID
T/F: Sinemet CR tablet CAN be cut in half
True
T/F: Rytary (carbidopa/levodopa ER capsule) can be sprinkled on a small amount of applesauce
True
What is a CI for Sinemet
Non-selective MAO inhibitors within 14 days, narrow angle glaucoma
Side effects of Sinemet
Nausea, dizziness, orthostasis, dyskinesias, hallucinations, psychosis
Can cause brown, black, or dark discoloring of urine, saliva or sweat and can discolor clothing; positive Coombs test: discontinue drug (hemolysis risk); unusual sexual urges, priapism
How many mg/day of carbidopa is required to inhibit dopa decarboxylate
70-100
Long-term use of Sinemet can lead to
fluctuations in response and dyskinesias
MOA of COMT inhibitors
increase the duration of action of levodopa; inhibit the enzyme COMT to prevent peripheral conversion of levodopa
