Parkinsons Disesae Flashcards
What’s the role of substantia nigra that dies or becomes impair in PD?
Dopamine (that’s why there’s a dopamine shortage in PD)
Primary s/sx of PD?
TRAP
Tremor - seen during rest, usually worsened by anxiety
Rigidity - arms, legs, trunk and face (mask-like face)
Akinesia/bradykinesia - lack of movement or slow initiation of
movement
Postural instability - poor balance, which may lead to freq falls
Other signs of PD?
Small, cramped handwriting (micrographia)
Shuffling walk
Stiff facial expression, reduced eye blinking
Muffled speech, drooling, dysphagia
Depression, anxiety (psychosis in advanced dx)
Constipation, incontinence
What’s frustrating and challenging about PD complications?
Eventually, even with high doses of the 2 most effective classes of drugs (Carbidopa/Levodopa and dopamine agonists) the “off” periods will increase
What has the highest efficacy for tx in PD pts with depression?
Tricyclic antidepressants-preferably secondary amines (desipramine and nortriptyline)
SSRIs or SNRIs commonly used but some concern they may contribute to tremor or increased serotonin syndrome risk in patients taking other serotonergic drugs
Whats preferred antipsychotic in PD pts (psychosis can present with advanced dx)?
Quetiapine (low risk of movement disorders, but will require monitoring due to metabolic complications, including blood glucose & cholesterol)
clozapine has low risk of worsening movement but high risk for agranulocytosis, seizures and other serious complications
List drugs that may worsen PD (drug-induced PD)?
Phenothiazines (Prochlorperazine, etc)-used for psychosis, nausea & agitation
FGAs-butyrophenones (esp, haloperidol-used for psychosis and behavior disorders) or droperidol used for nausea
SGAs Risperidone (Risperdal) at higher doses and paliperidone
Metoclopramide (Reglan) - dopamine blocking agent that is really cleared and can accumulate in elderly patients
Which agent is most commonly used and most effective and is sometimes better tolerated for initial tx in elderly?
Carbidopa-Levodopa (Sinemet)
What could be used for initial tremor in younger pts?
centrally acting anticholinergic-Beers criteria recommends to avoid these in elderly
Amantadine-useful for dyskinesia
MOA of Carbidopa/Levodopa?
Carbidopa Inhibits dopa decarboxylase, preventing peripheral metabolism of levodopa
(Levodopa is a precursor of dopamine-dopamine prodrug that’s converted to dopamine in the brain)
Brand name of Carbidopa/Levodopa
Sinemet
Sinemet CR
Rytary ER capsule
Duopa (enteral J-tube suspension)
T/F? Sinemet can be cut into half?
True-the CR tab can be cut in half at thescore line
BUT don’t crush or chew
ER (Rytary)-take whole or sprinkle on applesauce
How much Carbidopa is required to inhibit peripheral conversion (dopa decarboxylase) and to reduce nausea?
70-100mg of Carbidopa
SEs of Sinemet (Carbidopa/Levodopa)?
Nausea
Dizziness
Orthostasis
Dyskinesia (abnormal movement)
Brown, black or dark urine, saliva or sweat and discolor clothing
Sinemet (Carbidopa/Levodopa) and unusual sexual urges?
Sinemet (Carbidopa/Levodopa) may cause unusual sexual urges, priapism
Effect of Long-term use of Sinemet (Carbidopa/Levodopa)?
Response may fluctuate after long-term use and lead to dyskinesias
What does Sinemet (Carbidopa/Levodopa) need to be separated from?
Iron
May be protein
MOA of COMT-INHIBITOR?
Inhibit enzyme COMT to prevent peripheral and central conversion of levodopa
Role of COMT-inhibitor in therapy?
Used only with levodopa to increase levodopa duration of action- take 200mg PO with each dose of carbidopa/levodopa-max 1600mg/d
COMT-inhibitor agents?
Entacapone (Comtan)
Entacapone+Carbidopa/Levodopa (Stalevo)