3.3 Anti-Parkinson Drugs Flashcards
What environmental factor causes parkinson-like syndrome?
MPTP (dopamine neurotoxin)
A balance between what activity controls voluntary movements?
Dopaminergic + Cholinergic Activity
What was the first drug used to tx Parkinson’s?
Levodopa (L-dopa)
What does the drug interaction of Levodopa with sympathomimetic drugs (b-agonists) cause?
Cardiac stimulation
What does the drug interaction of Levodopa with Pyridoxine (vit B6) cause?
Dec efficacy of Levodopa
What does the drug interaction of Levodopa with antipsychotic drugs cause?
Dec efficacy of levodopa
What does the drug interaction of Levodopa with MAOI’s cause?
Hypertensive crisis
What is the peripheral decarboxylase inhibitor?
Carbidopa
Usually given as Sinemet = levodopa + carbidopa
What are the advantages of Carbidopa (Sinemet)?
- Inc 1/2 life of levodopa
- Dec peripheral side effects
- Diminished CNS (dopamine) fluctuations
What are the disadvantages of Carbidopa (Sinemet)?
Increased CNS side effects
What drug increases the synaptic [dopamine]?
Amantadine
What are the dopamine receptor agonists?
Bromocriptine + Pergolide
(ergot alkaloids)
Why is pergolide no longer available?
Assoc with valvular heart disease
What drug is a D3 agonist?
Pramipexole
What drug is a D2 agonist?
Ropinirole
What drugs are synthetic and sometimes used alone in early stage disease?
Pramipexole + Ropinirole
What drug can have an adverse interaction with ropinirole?
Ciprofloxacin
- Can inhibit CYP1A2 (metabolizes ropinirole)
- Dec metabolism + inc blood [ropinirole] = inc side effects
What drugs are linked to the rare side effect of compulsive gambling?
Pramipexole + Ropinirole
What are pramipexole + ropinirole also Rx for?
Restless leg syndrome
What drug is used for rescue of akinesia in “off” periods (when pt is unable to move)?
Apomorphine
How is Apomorphine delivered?
Subcutaneously, fast action
What should you pretreat Apomorphine with to prevent nausea?
trimethobenzamide
What is the function of Selegiline the MAO-B inhibitor?
- Dec “on-off” fluctuations
- Prolong usefullness of levodopa (# of yrs overwhich DOPA will be effective)
What is a newer MAO-B inhibitor?
Rasagiline
What are the COMT Inhibitors?
Entacapone + Tolcapone
What is the MOA of COMT inhibitors, Entacapone, Tolcapone?
- Inhibit peripheral metab of levodopa to 3-O-methyldopa (inhibits uptake of levodopa)
- Enhance uptake of levodopa
What are the anticholinergic drugs used to tx Parkinsonism?
Benztropine + Trihexyphenidyl
What are the potential drug interactions with anti-parkinson drugs?
- MAOI
- Catecholamines
- Anti-muscarinics
