Parkinson drugs Flashcards
what is Levodopa typically used for in Parkinson Disease
to control bradkinetic symptoms
MOA of Levodopa
converted to dopamine by DOPA decarboxylase at the presynaptic neuron to stimulate D2 receptors
Side effects of Levodopa (alone)
- GI: Anorexia, N/V
- CVS: Arrhythmias. tachycardia, postural hypotension
- Behavior: depression, anxiety, agitation, insomnia, confusion, hallucinations, nightmares, euphoria
- choreoathetosis of the face and distal extremities
- wearing off/ off and on phenomena
- mydriasis may precipitate glaucoma, gout, and taste abnormalities
- brown secretions
- peripheral neuropathies
contraindications of Levodopa(alone)
Psych patients (may exacerbate psychosis)
Angle closure glaucoma (may exacerbate mydriasis)
Peptic ulcer disease
melanoma
interactions of Levodopa
antacids decrease bioavailability
ACh drugs and antipsych drugs may decrease serum levels/ effects
combination with MAOIs can cause HTN crisis and hyperpyrexia
B6 increases metabolism
can be antagonized by phenothiazines when not used with carbidopa
MOA of carbidopa
reduces peripheral conversion of Levodopa to dopamine and inhibits aromatic amino acid decarboxylase
does Carbidopa cross the BBB
no
AChR antagonists used in Parkinson Disease
Benztropine
Trihexyphenidyl
When are AChR antagonists used for Parkinson Disease?
patients who are 65 or younger and have a disturbing tremor, but no gait disturbance or bradykinesia
MOA of AChR antagonists
inhibits excitatory cholinergic neurons to decrease the concentration of ACh
Side effects of Benztropine and Trihexyphenidyl
Agitation
confusion
Constipation
Delerium
Dry mouth
Memory loss
urinary retention
tachycardia
Cautions and contraindications of using AChR antagonists
Caution: patients with closed-angle glaucoma
Contraindications: memory impaired, confused, hallucinating patients
Interactions with AChR antagonists
has additive anticholinergic effects with antihistamines and phenothiazines
What are the MAO-B Inhibitors and what are they used for
Selegiline, Rasagiline, Safinamide
Reduces mild on-off/ wearing off phenomena
for patients with declining or fluctuating response to Levodopa
Decreases free radicals and inhibits disease progression
MOA of MAOI-B Inhibitors
selectively and irreversibly inhibits MAO-B to increase dopamine in basal ganglia