PARKINSON'S: DOPAMINE RECEPTOR AGONIST

Question 1

What are the two types of dopamine agonists?

Answer 1

1. Non-ergot derived
2. Ergot-derived

Question 2

MoA

Answer 2

Direct action on dopamine D2 receptors in striatum

Question 3

Non-ergot derived

Answer 3

Pramipexole
Ropinirole
Rotigotine (patch only)

Question 4

Ergot-derived

Answer 4

Bromocriptine
Cabergoline
Pergolide

Question 5

When would they be used?

Answer 5

Non-ergot derived are 1st line in patients whose motor symptoms do not affect QoL
OR as an adjunct to levodopa

Question 6

What are the other dopamine agonist’s other than Ergot/non-ergot derived?

Answer 6

• Amantadine (mainly for dyskinesia in later stage of parkinson’s)
• Apomorphine (sc injection)
  These do not fall under the category of Ergot and Non-ergot derived but still act as agonists on Dopamine receptors

Question 7

Side effects

Answer 7

Impulse control disorders
Excessive sleepiness/sudden onset of sleep
Psychotic symptoms (hallucinations, delusions)
Hypotensive reaction in first few days (warning: driving/operating heavy machinery)

same as levodopa except dyskinesia, response fluc

Question 8

SE of ergot-derived dopamine agonists

Answer 8

Fibrotic reactions
Pulmonary - dyspnoea, persistent cough
Retroperitoneal - abdominal pain + tenderness
Pericardial - cardiac failure

Question 9

Dopamine agonists vs levodopa

Answer 9

DA more likely to:
- hallucinations
- impulse control disorder
- sudden onset and excessive sleepiness

Levodopa more likely to:
- motor complications: response fluctation and dyskinesia

Question 12

Which type of dopamine agonist is least likely to be used and why?

Answer 12

Ergot-derived dopamine agonist
* Due to Lung and cardiac fibrosis MAJOR side-effect
* Chest X-ray may need to be performed before the commencement
* Monitor signs and symptoms of SOB, cough, chest pain, and abdominal pain