Dopaminergic Drugs for Parkinson's (Madopar and Sinemet) Flashcards
When are dopaminergic drugs used?
They are used early in parkinson’s disease when dopamine agonists may be preffered over L-dopa
When does levodopa become an integral part of parkinson’s management?
later in the disease
What is the pathology of parkinson’s disease?
loss of dopamine releasing neurons in the nigrostriatal pathway leads to dopamine deficiency. This causes the basal ganglia to inhibit the thalamus. The thalamus reduces excitatory input to the motor cortex —->bradykinesia + rigidity.
Why can pure dopamine not be given in the treatment of parkinson’s disease?
Dopamine cannot cross the blood brain barrier
How does Levadopa work?
Ldopa is a precursor of dopamine. It can enter the brain via a membrane transporter.
What are the adverse effects of dopaminergic drugs?
- nausea
- drowsiness
- confusion
- hallucinations
- hypotension
- “wearing off affect”
Why should dopaminergic drugs be used cautiously with the elderly?
-risk of confusion and hallucinations
Why is L-dopa always given with a peripheral dopa-decarboxylase inhibitor (such as carbidopa)
To reduce its conversion to dopamine outside of the brain
What drugs should not be used with dopaminergic agents?
1) Antipsychotics
2) Metoclopramide
*the effects of these drugs on dopamine receptors are contradictory.
What is Madopar?
Madopar AKA Co-Beneldopa
A mixture of benserazide hydrochloride and levodopa
What are the drug interactions of Madopar?
- Antihypertensive drugs e.g. ACEi, Betab, Ca2+CB
- Antipsychotics
- Metoclopramide
What is sinemet?
Carbidopa and Levadopa
