Parkinson's disease IRAT Dr. Thomason Flashcards
Why is levodopa-carbidopa reserved for later treatment if at all possible?
Mainly to prevent the development of dyskinesias to as late in therapy as possible.
Levodopa remains the most potent and effective treatment for the motor symptoms of Parkinson’s disease, such as bradykinesia (slowness of movement), rigidity, and tremor -> but associated with dyskinesia with long-term use
What is amantadine usually used for? What is the unusual adverse effect of amantadine?
It is mostly commonly used as an adjunct to help manage L-dopa-induced dyskinesia. An unusual side effect of amantadine is livedo reticularis (red-blueish skin discoloration)
Why do we need to pretreat with a certain medication before giving apomorphine and what is that medication?
-N/V are common adverse effects for sublingual and subq dosage forms,
-trimethobenzamide (antiemetic) should be administered prior to initiation of apomorphine
Key warnings associated with dopamine agonists?
-serious side effects: impulsive and compulsive behaviors, delusions/psychosis, and sleep attacks
-common adverse effects: nausea, confusion, drowsiness, hallucinations, lower-extremity edema, and orthostatic hypotension
-avoid in the elderly population
-slow dose titrations are required to minimize the development of these adverse effects, especially nausea.)
What is the first-line treatment for tremors?
-younger than 65: Anticholinergics (benztropine and trihexyphenidyl) or Levodopa-Carbidopa
-> Anticholinergics ADEs are better tolerated at younger age
-if older than 65: Levodopa-Carbidopa: but should be given late to prevent dyskinesia
-> not in patients younger than 65 because we need to increase the dose over time -> higher peak -> dyskenisia - we want to postpone dyskenisia as long as possible
How do we treat dyskinesia?
-provide smaller doses of carbidopa/L-dopa at the same or increased dosing frequency; reduce dose of adjunctive dopamine agonist; add amantadine
What are the main signs of idiopathic PD?
-bradykinesia (slowness of movement)
and at least one of these:
-tremor at rest
-ridigity
-postural instability (instability of balance)
-usually between 55 and 65
Which medication should be assessed to check for medication-induced PD?
-meds that block D2 receptor
-antipsychotics (haloperidol)
-metoclopramide
-phenothiazine antiemetics (prochlorperazine)
Non-motor symptoms of PD
-Anxiety, constipation, daytime sleepiness, depression, drooling (excess saliva), fatigue, overactive bladder
Which drug is FDA-approved for psychosis in PD?
Pimavanserin
What are adjunctives to carbidopa/l-dopa?
-COMT inhibitor
-MAO-B inhibitor
-A2AR antagonist
-dopamine agonist
-> Increase levels of dopamine
Why is L-Dopa combined with Carbidopa?
-L-dopa is the precursor of Dopamine and crosses the BBB
-Carbidopa is a L-amino acid decarboxylase inhibitor (acting peripherally and preventing the conversion to dopamine peripherally -> to reduce peripheral side effects like nausea)
What is the initial maintenance dose of Carbidopa/L-Dopa?
25/100 mg 3x a day = 75 mg of L-Dopa
there is no max dose -> but usually it is maxed at 1000 - 1500 mg per day
if they don’t respond to 1000-1500 mg they probably don’t have PD
What are diet concerns with Levodopa?
Protein interacts with L-Dopa
-dietary protein competes with L-Dopa for absorption in the gut
-should be taken with meal due to nausea but don’t have a protein-heavy meal before taking L-dopa
What are the 3 selective MAO-B inhibitors used for PD?
-Rasagiline
-Safinamide
-Selegiline
CAUTION: serotonin syndrome when used with serotonergic agents, meperidine or other opioid analgesics or
