Parkinson's Flashcards
- tremor, rigidity, mask like expression
- idiopathic (most common in elderly)
- complication of influenza, certain meds, MPTP, Shy DRager syndrome, CJD
Parkinson’s disease
- Parkinson’s pathophys:
- loss of _______ dopamine neurons
- loss of innervation of basal ganglia
- side effects in mesolimbic, mesocortical, and tuberoinfundibula paths
nigrostriatal
____ like receptors appear to be most important therapeutically, as part of indirect pathway
D2 like
permissive and synergistic interactions occur between ____ like and ____ like receptors, balance important for greatest efficacy
D1, D2
- synthesized from tyrosine with L-dopa as an intermediate
- transported in the brain by the tyrosine transporter
- then decarboxylated
dopamine
- reverse rigidity, tremor, bradykinesia and reduced facial expression
- improved mental function and sense of well being
- adverse: n/v due to stimulation of D2 receptors in CTZ, orthostatic hypotension due to stimulation of dopamine receptors in kidney and vasculature
- decreased prolactin, mydriasis, sweating, insomnia
L-dopa
- fluctuates in efficacy (on/off, bradykinetic episodes, wearing off)
- abnormal involuntary movements
- hallucinations, paranoia, mania, anxiety, depression
L-dopa long term side effects
absorption dependent on GI transit time, longer transit leads to more degradation in the gut and less absorption
L-dopa
blocks AADC in periphery, does not cross BBB, decrease the dose and side effects of L-dopa
carbidopa
MAO-B inhibitors that block catabolism of dopamine, used as adjunt to L-dopa
selegiline, rasagiline
COMT inhibitors, block catabolism of dopamine and L-dopa, used as adjunct to L-dopa
tolcapone (more potent, hepatotoxic)
entacapone (peripheral)
abrupt discontinuation can result in symptoms resembling neuroleptic malignant syndrome including fever, muscle rigidity, tachycardia, mental status changes
L-dopa
- block actions of striatal cholinergic interneurons
- less effective than L-dopa
- tertiary amines, better CNS penetration
- constipation, urinary retention, mental confusion, hallucinations
anticholinergics: trihexyphenidyl, benztropine, procyclidine
- antiviral (influenza A) may release dopamine and/or have anticholinergic properties
- less efficacious than L-dopa
- monotherapy or L-dopa adjunct, effective for a few weeks
- adverse: livedo reticularis, peripheral edema, headache
amantadine
inverse agonist and antagonist activity at 5-HT receptors, PD psychosis?
pimavanserin
