Parkinson 2- SG Flashcards
What is the precursor of Dopamine?
Levodopa/Carbidopa/L-dopa
- What is the best tx of a pt who is 65 yrs or older?
- Is useful if tremor is not controlled by an anticholinergic
- Most effective drug for symptomatic tx of PD
Levodopa / Carbidopa
Ultimately all pts w/ PD will require what med?
Levodopa / Carbidopa / l-dopa
Why is Carbidopa added to Levodopa?
It prevents the breakdown of Levodopa
Carbidopa inhibits peripheral metabolism of Levodopa via ___ ______.
Dopa decarboxylase
Ultimately leads to an increase in the fraction of the dose that reaches the brain.
Role of adding Carbidopa to Levodopa (prevents breakdown of Levodopa)
What 2 drugs interact w/ Levodopa/Carbidopa resulting in:
- diminished doses
- prolonged action
What would pt experience w/ this interaction?
COMT (peripheral & brain, prevent dopamine degredation)
MAO B inhibitors
Excess dopamine (hallucinations/schizophrenia) and EPS - extra priamital ability
Adverse effects of what drug?
- Drowsiness
- Dyskinesias
- **Motor Complications**
Levodopa / Carbidopa
MOA of what drug?
- Blocks the conversion of L-dopa into the inactive form of 3-O-Methyldopa (3-OMD)
- Prevents conversion of Dopamine to 3-methoxtyramine (3-MT)
- Provides greater % of l-dopa to cross BBB & Dopamine in brain
COMT inhibitor
(Entacapone & Tolcapone)
Which drug?
- Attenuate motor fluctuations in carbidopa/l-dopa treated pts
- Modest symptomatic benefit as monotherapy
- Benefit may be from neuroprotective effect
- NO benefit as a monotherapy as it may not get more levodopa into the brain
COMT inhibitors (catechol-O-methyl-transferase)
(Entacapone & Tolcapone)
Adverse effects of which drug?
- Relates to increased levels of L-dopa
- Dyskinesias
- Confusion
- Liver toxicity *
- Orthostatic hypotension
COMT inhibitors
(Entacapone & Tolcapone)
Tolcapone specifically toxic to liver**
Which drug has these drug interactions?
- L-dopa reduces dose
- Antidiarrheals reduce dose
COMT inhibitors
(Entacapone & Tolcapone)
What should you monitor in a patient taking COMT inhibitors (Entacapone & Tolcapone)?
LFTs
Which drug?
- MOA: stimulates dopamine activity on the nerves in the subtantia nigra and striatum
- Pramipexole is the “prototype”
- Causes doing things in excess like spending money / gambling
Dopamine Agonists
(Amantadine)
Adverse Effects of which drug?
- **Postural hypotension**
- Pulmonary fibrosis
- Confusion
- Hallucinations
- Sedation
- Vivid dreaming
- **Impulsive Behaviors**
(Underlined = Psychosis)
Dopamine Agonists
(Amantadine)
When should you consider giving pt Amantadine?
If pt is older and doesn’t want to go on l-dopa
Which drug?
- Enhances dopamine release
- Blocks glutamatergic N-methyl-D-aspartate (NMDA) receptors
Amantadine (Dopamine Agonist)
What 3 things does Amantadine (Dopamine Agonist) improve in PD pts?
- Tremors
- Rigidity
- Bradykinesia
Adverse effects of which drug?
- Dizziness
- Dry mouth
- Hallucinations
- Livedo reticularis
Amantadine (dopamine agonist)
- Which drug has adverse reactions similar to anticholinergics?
- What are the 5 effects?
Amantadine (dopamine agonist)
- Mad as a hatter
- Blind as a bat
- Dry as a bone
- Red as a beet
- Hot as a hair
- What drug provides “symptomatic benefit,”
- but less than that of dopamine agonists or carbidopa/l-dopa
- Useful add-on agent to attenuate dyskinesias
Amantadine
- An aporphine alkaloid originally derived from morphine, but lacks narcotic properties
- Bc of poor oral bioavailability due to extensive hepatic 1st pass metabolism
- Is administered subcutaneously
- Indicated for pts w/ advanced PD who are experiencing intermittent off episodes despite optimized therapy
Apomorphine
- Upon subcutaneous administration, apomorphine produces an “on” response within ___ minutes.
- Sites of injection (abd, UE, upper thigh) should be rotated to avoid development of ____ ____.
- Apomorphine elimination half life is approximately ___ minutes and duration of benefit can be up to ____ minutes.
- 20 mins
- Subcutaneous nodules
- 40 minutes
- 100 minutes
What should patients be “premedicated” w/ before receiving Apomorphine?
Trimethobenzamide
(antiemetic)
If drug overdose, give what med? Which causes nausea and vomiting.
Apomorphine
Tx of what effect?
- Increase frequency of carbidopa/L-dopa doses
- Add either COMT inhibitor or MAO-B inhibitor or dopamine agonist
End-of-dose “wearing off”
(motor fluctuation)
Tx of what effect?
- Give carbidopa / L-dopa on empty stomach
- Use carbidopa/L-dopa ODT
- Avoid carbidopa/L-dopa CR (long acting)
- Use apomorphine subcutaneous
“Delayed on”
“no on” response
Tx of what effect?
- Increase carbidopa/L-dopa dose
- Add a dopamine agonist or MAO-B inhibitor
- Utilize physical therapy along w/ assistive walking devices or sensory cues
- (rhythmic commands, stepping over objects)
Start hesistation (freezing)
Tx of what effect?
- Provide smaller doses of carbidopa/L-dopa
- Add amantadine
Peak-dose dyskinesia
A form of carbidopa / levodopa delivered in gel form, called enteral suspension
Duopa
- Used to treat the motor sxs of PD
- Surgical placement of enteral tube in stomach wall to place a tube in your intestine
- Pump then delivers ____ directly to the intestine
Duopa
Duopa uses the same active ingredients as orally administered ____ _____, but is designed to improve absorption and reduce off times by delivering the drug directly to the small intestine.
Carbidopa / Levodopa
What drug do you give on empty stomach?
L-lopa/Carbidopa
Surgery should be considered an adjunct to pharmacotherapy when pts are experiencing _____ or ______ or ______ despite an optimized medical regimen.
- frequent motor fluctuations
- disabling dyskinesia
- tremor
____ DBS (Deep Brain Stimulation) is very effective for suppressing tremor specifically ___ tremor, but it does not significantly improve the other parkinsonian features (bradykinesia, rigidity, motor functions, or dyskinesias)
- Thalamic
- arm
Both ____ and ____ are associated w/ improvements in tremor, rigidity, bradykinesia, motor fluctuations, dyskinesia, and activities of daily living, however, _____ allows for greater reduction in medications.
- STN and GPi DBS
- STN DBS
As with pharmacotherapy, DBS uncommonly improves ____ or _____.
Gait or postural instability
- Excess dopamine results in ______ sxs
- When we tx _____, it looks like Parkinsons
- schizophrenia
