Pharmacology S11 Flashcards
Ergot dopamine agonist
Bromocriptine
Pergolide
Non ergot DA agonist
Pramipexole
Ropinirole
Dopamine efect at
Low
Intermediate
High doses
At low doses it acts on D1 receptors as reno vasodilators can lead to hypotension
At intermediate doses it acts on B1 receptors in the heart causing increase contractility &HR which can lead to arrhythmia
At higher doses it acts on a1 receptors causing vasoconstriction which can lead to HTN
Dopamine adverse effect
Nausea vomiting
Hypotension
Cardiac arrhythmia
At higher doses lead to HTN
Ergot DA agonist side effects
Peripheral vasoconstriction..
Pulmonary & retroperitoneuim fibrosis ..
Central side effect .. psychosis .. delu… and hallucination
Side Effects of L Dopa
- Nausea and vomiting
- Postural hypotension
- Hallucinations and pychosis
- Involuntary movements
- Loss of efficacy
Cardiac arrhythmia ..
Formulations of L Dopa
- Co –Beneldopa (madopar)
* Co – Careldopa (sinemet)
L Dopa Failure
- Occurs after 5 years on average.
- Cause unknown
- Dyskinesias.
- Wearing off effects
- Motor fluctuations
Management of L Dopa Failure.
- Avoidance
- Lower dosages
- More frequent administration
- Additional pharmacotherapy
Dopamine Receptor Agonists
- Ropinirole
- Pramipexole
- Pergolide
- Cabergoline
- Bromocryptine
- ( Apomorphine)
DA v L Dopa
- Less effective
- More side effects
- More expensive.
- Do not cause dyskinesias.
- May be neuroprotective.
When to use DA agonists
Early- to avoid long term complications
- Used for younger patient (< 65-70 )without dementia & hallucinations
Later - to treat motor fluctuations
MAOI inhibitors -
selegeline
rasageline
COMT inhibitors
entacapone
tolcapone
Amantadine
- Inhibits DA reuptake.
- Has weak anti PD effect.
- Moderate effect against dyskinesia.
Anticholinergic Therapy & side effect
- Acetyl Choline antagonises DA.
- Anticholinergics effective for tremor.
- Major side effects; Bladder . Vision. Dry mouth. Memory.
Complication of Parkinson’s disease
- Sleep disorders
- Neuropsychiatric illness like depression and dementia
- Autonomic dysregulation like orthostatic hypotension Constipation and erectile dysfunction …
Prognosis of Parkinson’s disease
- PD is a progressive disease
- Pharmacological treatment may reduce progression
- Mortality ratios are around twice those of unaffected people
Multiple system atrophy (MSA)
- Is another neurodegenerative disease
- Occurs in sporadic cases
- Clinical features of PD
– Without tremor
– Autonomic failure
• Neurodegeneration is more widespread involving the cerebellum and extrapyramidal tract.
Multiple system atrophy
ttt
Levodopa for parkinsonian features
Na,fluff intake ,pressure stockings ,midodrine, fludrocortison foe orthostatic hypotension
Oxybutinine or tolterodine for urinary incontenence or frequency
Sildenafil ( vigra ) for impotence
Selective serotonin reuptake inhibitors for depression
No good ttt of ataxia or dementia
