Parkinson's meds Flashcards
sxs of Parkinson’s result from loss of what in where?
dopamine-secreting (dopaminergic) cells in the pars compact region of the substantia nigra
primary defect in parkinson’s?
loss of dopamine in nigrostriatal pathway
4 pathways of dopamine?
nigrostriatal, mesocortical, mesolimbic, mtuberoinfundibular
disruption of dopamine along non-striatal pathways results in what ssxs?
depression, dementia, psychosis
major sxs of parkinsons? other sx?
tremor at rest
rigidity
bradykinesia and akinesia
postural instability - slow and reduced amplitude gait w/small, rapid, stutter-steps forward
stooped or flexed posture is common
can also impair nerve endings in the heart that regulate the release of NE which could cause an abrupt drop in BP (orthostatic hypotension and bradycardia)
masked facies/drooling
speech problems - vocal cords can be affected causing monotonous, whispery, soft speech qualities
difficulty swallowing
micrographia
urinary incontinence typically occurs late in dz progression
fatigue
depression
anxiety or panic attacks
dementia is a later development in 20-40% of all Parkinson’s pts
gravitational line and what does it encourage?
ear to acromion to greater trochanter to calcaneus which tilts us forward so its easier to walk
first MC sx of parkinson’s?
tremor
can start in one finger and spread over time to involve entire arm
often rhythmic, 4-5 cycles per second, frequently causes pill-rolling action
can occur when limb is at rest of when held in a stiff unsupported position
disappear during movement and do not occur during sleep
how does dementia present in Parkinsons?
typically starts w/slowing of mentation, progressing to difficulties w/abstract thought, memory and behavioral regulation
what can you see in the brain in Parkinson’s?
Lewy bodies = clusters of alpha-synuclein protein
accumulate inside the neurons
tremor usu begins where?
beings in upper extremities and are usu UL or asymmetrical at onset of dz
if metabolic cause of a tremor, how will it present?
will be BL, whereas Parkinson’s will be a UL tremor
cause of Parkinson’s?
idiopathic for the most part - not clear what causes the death of neurons and subsequent dopamine loss
small portion have an identifiable genetic defect
possible environmental role in Parkinson’s development?
environmental toxins, infxns and other triggers can provoke excessive production in the body of ROS and free radical damage which may lead to nerve cell death
what %age of dopamine has to be gone before usu see sxs?
75% of dopamine in substantia nigra and corpus striata have usu been lost before see sxs of Parkinson’s
main drug to tx Parkinson’s? long term complications?
levodopa - a dopamine precursor
long term complications: motor fluctuations, dyskinesias, mental status changes
why can’t you just give dopamine?
b/c it can’t cross the BBB
main SE of levodopa? what do you combine it with to avoid that SE?
levodopa + carbidopa to prevent the nausea that comes with levodopa tx
chief SEs of levodopa/l-dopa? via what MOA? secondary SEs are from what?
chief: N/V, anorexia induced by stimulation of dopamine receptors in the GI tract and chemotrigger receptor zone in the brain
secondary SEs from drug not working anymore - hypotension, choreiform movements, insomnia, anxiety
what is levodopa usu co-administered with?
combined w/peripheral dopa-decarboxylase inhibitor such as carbidopa or benserazide in order to prevent it from being broken down prematurely and converted into dopamine in the adrenal glands or other peripheral tissues = more levodopa for the brain
3 MC used meds which contain levodopa w/a peripheral dopa-decarboxylase inhibitor?
levodopa + carbidopa/sinemet
levodopa + benserazie/prolopa
levodopa + carbidopa and entacapone/stalevo
(entacaopne is a COMT inhibitor)
2 benefits of entacapone?
when administered in conjunction w/L-dopa the bioavailability of L-dope is increased and it’s passage across the BBB is increased
most common SE of entacapone?
dyskinesia
also N/V, diarrhea, abd pn