Parkinson's Drug Flashcards
Cardinal signs of Parkinson’s disease
Resting tremor
Bradykinesia
Postural instability
Rigidity
Etiology of PD
degeneration of dopamine producing neurons in the substantia nigra compacta in the midbrain
imbalance of decrease in dopamine and increase in AcH
others: 5-HT, NE, Glutamate, GABA
Levodopa treatment
goal: increase dopamine in the basal ganglia
can’t directly administer dopamine due to BBB
precursor L-Dopa adminstered to eventually cross BBB and become dopamine
Carbidopa treatment
L-dopa becomes dopamine before reaching the brain
Carbidopa prevents premature conversion of L-dopa into dopamine by inhibiting the dopa decarboxylase enzyme
often used in conjunction with L-dopa
Synthesis of Dopamine
tyrosin through tyrosine hydroxylase becomes
dopa through dopa decarboxylase becomes
dopamine
L-dopa side effects
GI irritation, hypotension
Dyskinesia, freezing gait
psychotropic effect, others
L-dopa fluctuation
End of dosage fluctuation
decrease response due to end of dosing cycle
On-off fluctuation
fluctuation of response during the cycle of dosing
L-dopa tolerance
decrease in benefit is seen within 4-5 years due to tolerance
may postpone usage for more severe cases
may want to use immediately if case is progressed already
Dopamine agonist
can cross the BBB
longer half life=more stable response to drug
may be used as the initial tx of PD
neuroprotective?
Dopamine agonist associated side effects
naseua, vomitting
confusion, hallucination
postural hypotension, increase dyskinesia
COMT inhibitors
inhibits the enzyme that degrades dopamine
increases “on” time and decreases fluctuation
often used in conjunction with L-dopa and Carbidopa
COMT inhibitors associated side effects
GI irritation diarhhea
OH, increased dyskinesia
Anticholinergic agents
decrease AcH influence= decreased rigdity and tremor
limited use of these drugs due to the Anticholinergic package effects
MAO-B inhibitors
prolongs the effect of dopamine in the brain
combined with L-dopa= increase effect time
neuroprotective
no associated side effects
Amantadine
antiviral (discovered by chance)
NMDA blocker that decreases excitatory Glut activity
decreases chance of dyskinesia
