Parkinson's Disease Flashcards
Symptoms of Parkinson’s?
Tremors
Rigidity (arms, legs, trunk)
Bradykinesia
Akathesia
Postural instability
Cause behind Parkinson’s?
Loss of balance between dopamine and Ach in substantia nigra.
High Ach and low dopamine
Antiparkinsonism drugs
- Levodopa + Carbidopa
- Amantadine
- Dopamine receptor agonists: ropinirole, pramipexole, rotigotine, bromocriptine, apomorphine
- MAO B inhibitor: selegline and rasagline
- COMT inhibitors: entecapone and tolcapone
What are levodopa’s problems?
- Must be used in the early stages of disease where at least 20% of dopaminergic neurons are functioning
- Lots of peripheral side effects
- Must be given in high doses 80% of it is converted peripherally to dopamine.
- Wearing off effect
Advantages of combining levodopa and carbidopa?
- decreasing peripheral side effects
- lowering the dose of levodopa by 4 or 5 fold
Solution when levodopa starts wearing off?
Lower the dose increase the frequency and administer COMT inhibitors
Administer dopamine receptor agonists
CNS actions of dopamine?
- Mesolimbic/mesocortical
High dopamine ➡️ psychosis
- Substantia nigra
High dopamine ➡️ antiparkinsonism
- Chemoreceptor trigger zone
High dopamine ➡️ emesis
- Pituitary gland
High dopamine ➡️ low prolactin
Peripheral effects of dopamine?
- Beta 1 on heart ➡️ high inotropic, high chronotropic, high dromotropic
- Alpha 1 in eyes ➡️ mydriasis
- D1 and D2 in blood vessels ➡️ vasodilation
Peripheral adverse effects of levodopa and carbidopa?
CTZ: N&V, anorexia
B1: cardiac arrhythmias, tachycardia
Alpha 1: mydriasis
D1 and D2: hypotension
Blood dyscriasis (hemolytic anemia) and positive coombs test
Brownish color of salive and urine
CNS adverse effects of levodopa and carbidopa?
Visual and auditory hallucinations
Dyskinesia
Mood changes
Depression
Anxiety
Interactions of levodopa?
Vitamin B6 increases the breakdown of levodopa and decreases its effectiveness
Contraindicated with antipsychotic drugs
Increases symptoms in psychotic patients
Don’t administer with MAO inhibitors: hypertensive crisis
Glaucoma
Cardiac arrythmias
Mao b inhibitors?
Selegline
Rasagline
Mao b inhibitors moa?
Selectively inhibit mao b responsible for breaking down dopamine
It loses its selectivity at high doses
COMT inhibitors?
Entacapone
Tolcapone
COMT inhibitors adverse effects?
Tolcapone: fulminating hepatic necrosis
Postural hypotension
Nausea
Anorexia
Hallucinations
Dopamine receptor agonists?
Bromocriptine
Ropinirole
Pramipexole
Rotigotine
Apomorphine
Is bromocriptine used for parkinsons?
No, it has very strong side effects
Its used for galactorrhea
In what stage of parkinsons is apomorphine used?
In severe and advanced stages as an injectable dopamine agonist
Side effect of apomorphine
Severe nausea and vomiting
Antidote of apomorphine
Trimethobenzamide
Side effects of bromocriptine
Worsening of ulcer
Peripheral vasoconstriction
Cardiac issues
Nausea and vomiting
Hallucinations
Orthostatic hypotension
When are dopamine receptor agonist used?
When levodopa starts wearing off
Which dopamine receptor agonist is available as a patch
Rotigotine
Restless leg syndrome drugs?
Ropinirole
Pramipexole
Rotigotine
