pharm of parkinson Flashcards
drugs used for parkinson
- L-dopa and carbidopa
- dopamine receptor agonists
- anticholinergic drugs
- monoamine oxidase inhibitors (MAOI)
- Carechol-o-methyl transferase inhibitors (COMTI)
- amantidine
amantidine function
- increases availability of endogenous dopamine in caudate and putamen
- glutamate receptor (NMDA) antagonist
COMTI function
inhibits COMT, part of pathway of L-DOPA and dopamine
L-DOPA
is an intermediate product in the synthesis of dopamine endogenously
Carbidopa function:
cannot cross the BBB but can inhibit degradation of L-DOPA in the gut and liver by blocking dopamine decarboxylase.
Give L-DOPA with carbidopa:
you deliver a high dose of L-DOPA to the brain where it can be converted to dopamine in the basal ganglia.
The D2 receptor is on the
indirect pathway and is Gi so it suppresses the indirect pathway, which is normally inhibitory to the thalamus.
L-DOPA in Parkinson’s
Parkinson’s is disease of too little dopamine synthesis, giving L-DOPA can help replenish some of the missing dopamine in the brain.
L-DOPA absorption
- orally
2. crosses the blood brain barrier.
dopamine receptor agonists function
- bind to D2 receptors
- agonize dopamine effects
- do not replace L-DOPA, so have longer half lives
anticholinergic drug function
- when there is a loss of dopamine, there is an overactivity of cholinergic interneurons in putamen and caudate (DA inhibits ACh)
- block muscarinic receptors
- less effective than L-DOPA
MAOI function in parkinson
- MAO is responsible for breaking down DA into DOPAC
- By inhibiting this action, the effects of DA can be potentiated
- MAO-A and B
L-DOPA (with carbidopa)
Class
Endogenous precursor to DA
L-DOPA (with carbidopa) SE
- Acute: Nausea, hypotension, depression and psychosis
2. Chronic: dyskinesia and psychosis
Bromocriptine Class
D2 receptor agonist
