Parkinsons + movement disorders Flashcards
Normal function/balance between dopamine and ach
Dopamine inhibits the release of GABA in the striatum. This allows movement to occur
Ach excites the release of GABA in the striatum. This slows down movement.
Parkinson’s pathology
Dopamine neuron death changes the balance between dopamine and Ach. Leads to more Ach exciting the release of GABA= decreased movement. Reduction of excitation of the motor neurons in the spinal cord.
Problems with using L dopa
Taken up by all brain dopaminergic neurons. May induce other behavioral changes- psychotic.
Adverse effects of Levoopa
Anorexia, tachycardia, psychiatric problems, nausea, hypotension.
Carbidopa
Antagonist of the enzyme that converts levodopa to dopamine in the peripheral tissues. = more to CNS! Basically makes levodopa more bioavailable.
Co admin with levodopa. Does not cross BBB.
COMT inhibition
- MOA
- Adverse effects
This transferase interferes with levodopa uptake. Entacapone inhibits this enzyme and increases bioavailability of levodopa.
adverse effects: GI, abdomen pain, orthostatic hypotension, sleep disturbances
Amantadine MOA
MOA in parkinsons is unknown, but it is an antiviral that inhibits uncaring.
Somehow enhances release of dopamine.
What type of Parkinson’s tx is effective beyond point at which other treatments fail?
DA agonists. The dopamine receptors persist even long after loss of nigrostriatal neurons.
What drug group is contraindicated in patients treated for psychosis?
Dopamine receptor agonists
Side effects of dopamine receptor agonists
Anorexia
GI
orthostatic hypotension
psychiatric reactions- contra in pts treated for psychosis
How do the anti-muscarinic drugs tx parkinsosn?
Decrease Ach levels to restore balance between Ach and dopamine.
Useful in early stages.
Can cause blurry vision and contraindicated in glaucoma.
What drug class can cause blurry vision and is contraindicated in patients with glaucoma?
Anti-muscarinic
Wilson’s disease
Disorder of copper metabolism.
Increased copper concentrations can cause neuro dysfunctions- tremor, rigid, dysphagia.
Watch the K for kayser fletcher ring.
Can use penicillamine, a chelating agent to remove the copper.
