Drugs for movement disorders Flashcards
levodopa
D2 receptor agonist Adverse effects: - nausea, anorexia due to activation of chemoreceptor zone in brainstem - Postural hypotension - hypertension when given with MOA inhibitors - increases arrhythmias - dyskinesia - mental effects (depression, anxiety - on:off phenom
Carbidopa
DOPA decarboxylase inhibitor
doenst cross BBB
increases plasma levels and half life of levodopa
apomorphine
reduces on-off phenomenon experienced with levodopa therapy, sub-q injections
post-synaptic dopamine D2 agonist
Levodopa adverse effects
nausea, anorexia postural hypotension hypertension with non-selective MOA inhibitors increases chance of arrythmias dyskinesia mental effects on-off phenom
Drug interactions and contraindications of Levodopa
MOA inhibitors (hypertensive crisis) psychotic patients open angle glaucoma melanoma (levodopa is precursor of melanin) peptic ulcers
Bromocriptine
Ergot alkaloid D2 agonist
treats endocrine disorders too
Contraindicated in pts with peripheral vascular disease
Dopamine receptor agonists
lower incidence of fluctuations and dyskinesias that occur with long term levodopa
if pt doesn’t respond to levodopa then won’t respond to dopamine agonist
Pramipexole
D3 receptor agonist
Treats restless leg syndrome too
most excreted unchanged in urine (check kidney function)
Ropinirole
D2 receptor agonist
approved for RLS
met by CYP1A2
Adverse effects of Dopamine agonists
Anorexia, nausea, constipation, acid reflux
Postural hypotension
if peripheral edema and arrhythmias develop then discontinue
dyskinesias
mental disturbances (more severe than levodopa)
MOA inhibitors
Selegiline
Rasagiline
Both MAO-B inhibitors
Non-selective MAO inhibitors are avoided to prevent hypertensive crisis
Selegeline
Irreversible MOA-B inhibitor
reduces fluctuation response in those on levodopa
contraindicated in pts taking tricyclic antidepressants, SSRI’s
Rasagiline
Irreversible MAO-B inhibitor, more potent than selegeline
neuroprotective agent for early symptoms of PD
COMT inhibitors
Tolcapone, entacapone
inhibit peripheral metabolism of levodopa
Talcapone
peripheral and central inhibitor of COMT
Increases liver enzyme levels and can cause acute hepatic failure
orange discoloration of urine, diarrhea, abd pain
amantadine
antiviral agent
increase synthesis, release or reuptake of dopamine
may cause livedo reticularis (purplish mottled discoloration of skin on legs)
anticholinergic drugs
mAChR antagonists
improve tremor and rigidity but not bradykinesia
Benztropine
mAChR antagonist for PD
biperiden
mAChR antagonist for PD
orphenadrine
mAChR antagonist for PD
procyclidine
mAChR antagonist for PD
trihexyphenidyl
mAChR antagonist for PD
Tremor tx
metoprolol or propranolol primidone (symptomatic) topirimate alprazolam Botulinum toxin A
tx or huntington chorea
reserpine
tetrabenazine
both block vesicular monoamine transporter and deplete cerebral dopamine stores
tetrabenazine has less peripheral activity
