NERVOUS SYSTEM: DOPAMINERGIC DRUGS FOR PARKINSONS Flashcards
1
Q
DOPAMINERGIC DRUGS FOR PARKINSONS: INDICATIONS
A
- Early Parkinson’s disease
- Later PD
- Secondary Parkisonisml
2
Q
DOPAMINERGIC DRUGS FOR PARKINSONS: MOA
A
- Def of dopamine in the NIGROSTRIATAL PATHWAY
- Via direct and indirect circuits, this causes the basal ganglia to exert greater inhibitory effects on the thalamus which, in turn, reduces excitatory input to the motor cortex.
- By contrast, levodopa (L-dopa) is a precursor of dopamine that can enter the brain via a membrane transporter. Ropinirole and pramipexol are relatively selective agonists for the D2 receptor, which predominates in the striatum
3
Q
DOPAMINERGIC DRUGS FOR PARKINSONS: ADVERSE EFFECTS
A
- Nausea
- Drowsiness
- Confusion
- Hallucinations
- Hypotension
- Wearing off effect
- Dyskinesias at the beginning of dosage interval
ON/OFF EFFECT
4
Q
DOPAMINERGIC DRUGS FOR PARKINSONS: WARNINGS
A
- Elderly
- Those with existing cognitive or psychiatric dx due to risk of causing confusion and hallucinations
- Used cautiously in those with CVD risk
5
Q
DOPAMINERGIC DRUGS FOR PARKINSONS: IMPORTANT INTERACTIONS
A
- Levodopa is always given with a peripheral dopa-decarboxylase inhibitor (e.g. carbidopa) to reduce its conversion to dopamine outside the brain
- This desirable interaction reduces nausea and lowers the dose needed for therapeutic effect.
- Dopaminergic agents should not usually be combined with antipsychotics (particularly first-generation) or metoclopramide because their effects on dopamine receptors are contradictory.
6
Q
DOPAMINERGIC DRUGS FOR PARKINSONS: EXAMPLES
A
- levodopa (as co-careldopa, co-beneldopa)
- ropinirole
- pramipexol