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27 Cards in this Set
- Front
- Back
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MOA of Levodopa?
used to tx? |
immediate precursor of dopamine which will cross the blood brain barrier
conversion of l-dopa to dopamine in CNS, thus increasing dopamine in the basal ganglia tx-->Parkinson's |
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what limits the use of levodopa?
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need to have dopamine neurons to convert L dopa to dopamine
over time these neurons are dying |
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what are the clinical changes you will see in pts who take in levodopa?
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Bradykinesia and rigidity are reversed quickly; reversal of tremor requires continued therapy
Changes in mood associated with PD are reversed; patients more alert and interested in environment. Dementia may not reverse |
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what are the cardiovascular and endocrine effects of L-dopa
(not sure how important this is but here you go anyways) |
Cardiovascular
Asymptomatic (usually) orthostatic hypotension Dopamine stimulates both alpha and beta receptors Cardiac stimulation Endocrine Dopamine important in regulation of anterior pituitary function Prolactin secretion inhibited Little change in growth hormone secretion |
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what are the short and long term side effects of L-Dopa? 2 big ones here
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Early side effects
Dose dependent; tolerance may develop GI – nausea, vomiting (80%) CVS – orthostatic hypotension (30%), cardiac arrhythmias Long term effects – severity correlates with the degree of clinical improvement, duration of therapy and dose. No tolerance develops. ***Abnormal involuntary movements (dyskinesia)*** (80% after 1 year). Reduction in dosage required Psychiatric and behavioral disturbances (15%) ***“On-Off” syndrome – oscillations in performance involving rapid changes from akinesia to dyskinesia (different from “end of dose”). ** |
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antipsychotic drugs have what effect on L-dopa?
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Typical” antipsychotic drugs are dopaminergic antagonists and thus counteract the effects of dopa
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MAOi interact how with L-dopa?
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MAO inhibitors increase the effects of dopa, may lead to hypertensive crises
note: Tricyclic antidepressants – may aggravate hypotensive symptoms |
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Carbidopa MOA?
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prevents PERIPHERAL conversion of Dopa to Dopamine
allows more L-dopa to get to the brain to be converted allows for lower dose of L-dopa to be used decreases peripheral side effects of L-dopa (less CV, NV) |
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what are the side effects of Carbidopa?
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remember, it decreases L-dopa side effect peripherally BUT
increased central side effects of dopa Early development of long term side effects possible Activation of COMT pathway --so in a way it may progress the disease more quickly (Parkinsons) |
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What kind of drug is Tolcapone?
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COMT inhibitor
thereby increasing the duration of action of l-dopa and dopamine (COMT inactivates l-dopa and dopamine). Works in CNS and periphery |
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What kind of drug is Entacapone?
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COMT inhibitor
thereby increasing the duration of action of l-dopa and dopamine (COMT inactivates l-dopa and dopamine). only works in the periphery |
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major tox of tolcapone? is this a problem in entacapone?
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Hepatotox
NO |
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Ropinirole is what kind of drug?
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non-ergot DA agonists
Direct stimulation of DA receptors in striatum |
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pramipexole is what kind of drug?
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non-ergot DA agonists
Direct stimulation of DA receptors in striatum |
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what is one of the few drugs that may slow the progression of Parkinsons?
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pramipexole
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impulse control problems is a side effect of what drugs?
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Non-ergot DA agonists
pramipexole/Ropinirole |
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what is a unique side effect of pramipexole?
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Pramipexole can cause sudden onset of sleep with no warning
MOA:Non-ergot DA agonist |
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Use for Apomorphine?
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non-ergot DA agonist recently approved for rescue treatment of PD patients with “off” episodes (freezing).
Adverse effects include vomiting, orthostatic hypotension and syncope. |
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How is Amantadine used in Parkinson's?
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An antiviral agent found to be effective against PD
. Apparently acts by increasing dopamine release from intact dopaminergic neurons. Also blocks NMDA receptors. Is effective quickly but for short time (6-8 weeks). Also used to control dyskinesias occurring with l-dopa therapy late in progression of disease. |
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Hallucinations, confusion, and nightmares
Insomnia, dizziness, lethergy, slurred speech Long term use may result in livido reticularis (net like discoloration of the skin) are adverse rxns of what drug? |
Amantadine
Apparently acts by increasing dopamine release from intact dopaminergic neurons. Also blocks NMDA receptors. |
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Trihexyphenidyl is what kind of drug? how does it help with PD?
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Anticholinergic drugs - used as adjunct to l-dopa therapy
Decrease tremor Little effect on rigidity and bradykinesia Generally have little peripheral effect, but may reduce some autonomic symptoms |
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benztropine is what kind of drug? how does it help with PD?
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Anticholinergic drugs - used as adjunct to l-dopa therapy
Decrease tremor Little effect on rigidity and bradykinesia Generally have little peripheral effect, but may reduce some autonomic symptoms |
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adverse effects of anticholinergic drugs used for PD?
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CNS – confusion, delerium, somnolence, hallucinations (try to avoid them in old people)
Peripheral – may produce cycloplegia, constipation, and urinary retention in certain patients |
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MOA of Selegiline?
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MAO B Inhibitors
MAO B metabolizes dopamine--prevents this NEUROPROTECTIVE in Parkinson's dz (1st line) |
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MOA of Rasagiline?
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MAO B Inhibitors
MAO B metabolizes dopamine--prevents this |
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Pt has Parkinson's, what should you use first? second? third?
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Selagilline for neuroprotection
Dopamine Agonists (pramipexole) Levodopa COMT inhibitor (one of the capones) All others |
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Tetrabenazine is used to treat what?
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approved for treatment of chorea associated with Huntington's Dz
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