Parkinsons Meds

Question 1

Levodopa

L-Dopa

CLass
MOA
IND

Answer 1

Dopamine precursor
Parkinson’s
Transformed into DA by dopa-decarboxylase in basal ganglia & other tissues

Question 2

Levodopa

L-Dopa

SE

Answer 2

Severe protracted nausea, vomiting, anorexia
Hypotension, choreiform movements (involuntary abN movement of extremities, body, head, neck), insomnia, anxiety

Nausea, sleepiness, dizziness, involuntary writhing movements, visual hallucinations – most of these disappear/diminish as tx continues

Question 3

Levodopa /L-dopa

Charcteristics

Answer 3

Rapidly metabolized in peripheral tissues – 1% administered dose reaches CNS

Not used by itself anymore
Usually combined w/ peripheral dopa-decarboxylase inhibitor to prevent L-dope from being prematurely converted into DA in adrenal glands or peripheral tissues

Wearing off phenomenon: tx only lasts 5 years
On-off phenomenon: unpredictable fluctuations between mobility & immobility

CI: MAO-I hypertensive crisis, schizophrenia (worsening of sx), DA-blocking antipsychotic

Question 4

Entacapone
CLass
ind
MOa
SE

Answer 4

COMT inhibitor

Parkinson’s

Increase L-dopa bioavailbility, facilitates passage of L-dopa across BBB

Dyskinesia (at beginning of tx, then diminishes)
N/V/D, Abd pain

Question 5

L-dopa with Carbidopa

Sinemet

Answer 5

Dopamine precursor (L-dopa)
Peripheral DA decarboxylase inhibitor (Carbidopa)
Parkinson’s
Increases DA levels in brain, especially in substantia nigra
N/V, fainting
Hallucinations, nightmares, dyskinesias, serpentine-like movement (chorea)
PO, TID-QID
DA cannot cross BBB, but L-dopa can

Combination improves action of L-dopa & reduces many SE, particularly nausea

Question 6

Bromocriptine/Parlodel

Class
INd
MOA

Answer 6

Dopamine agonist
Parkinson’s
Prolactin-secreting adenomas
Acromegaly

Mimics DA in stimulation of DA receptor sites

Potent agonist at D2 receptors & various 5HT receptors

Question 7

Bromocriptine/Parlodel

SE

Answer 7

Nausea, hypertension or hypotension, confusion, hallucinations, HA, depression, dyskinesia, possible seizures

Uncommon: pulmonary fibrosis (w/ extremely high doses)

At initiation: severe HA, hypertension, seizures, stroke, MI

Question 8

Bromocriptine/Parlodel

CHar

Answer 8

PO
Crosses BBB
Used to delay need for L-dopa tx or audment L-dopa therapy

Inhibits GLT1 transporter release of glutamate
Monitor BP at initiation of tx

Must titrate up slowly to prevent adverse effects

Question 9

Benzotropine

Cogentin

Class
ind
moa
se

Answer 9

Anticholinergic
Parkinson’s (esp. when tremor/drooling are predominant sx)
Anticholinergic antagonist at muscarinic receptor sites
Dry mouth, blurred vision, urinary retention, constipation, confusion, drowsiness, disorientation, memory impairment, visual hallucinations, possible exacerbation of pre-existing psychotic sx

Question 10

Benzotropine

Cogentin

Char

Answer 10

PO – used as single therapy or in adjunct to other Rx

Tx tremor/drooling, less useful in tx bradykinesia & rigidity
Appears to help w/ cognitive sx
Used to diminish SE of antipsychotic drugs

Toxic psychosis – may look like atropine poisoning or antihistamine OD – tx w/ Physostigmine

Question 11

Amantadine

Symmetrel

Answer 11

Anti-Parkinson’s
Anti-viral

Parkinson’s
Influenza A

Unclear – probable NMDA receptor antagonism

Light headedness, confusion, drowsiness, nightmares, dry mouth, constipation, urinary retention, nausea, vomiting

PO
Used in attempt to delay onset of initiating L-Dopa therapy – improves bradykinesia, tremor & rigidity

Diminished/absent response w/in 6 months