Parkinsons Disease

Question 1

What is Parkinson’s disease?

Answer 1

A chronic, progressive neurodegenerative condition resulting from the loss of dopamine containing cells of the substantia nigra

Question 2

What is the aetiology of Parkinson’s disease?

Answer 2

• Genes (Family history in first degree relatives)
• Environment (Traumatic brain injury, pesticide/herbicide exposure)

Ultimately idiopathic

Question 3

What are the motor symptoms of Parkinson’s disease?

Answer 3

• Bradykinesia
• Resting tremor
• Extrapyramidal rigidity
• Postural instability

Question 4

What two classes of drugs commonly cause drug-induced Parkinsonism?

Answer 4

• Antipsychotics (1st gen more likely)
• Antiemetics (Prochlorperazine, metoclopramide)

Question 5

What are the initial treatments (first line) in early Parkinson’s?

Answer 5

• Levodopa + DOPA-decarboxylase inhibitor
• Dopamine-receptor agonists
• Monoamine-oxidase B inhibitors

Question 6

How does levodopa work and what is it given with?

Answer 6

Replenishes depleted striatal dopamine

Given with extracerebral dopa-decarboxylase inhibitor
- Benserazide (co-bendelopa) and carbidopa (co-careldopa)

Question 7

What are examples of Moniamine oxidase B (MAOB) inhibitors and how do they work?

Answer 7

Rasagiline and selegiline HCl

Slow the breakdown of dopamine in striatum

Question 8

What are examples of dopamine agonists, how do they work and what are their risks?

Answer 8

Pramipexole, ropinerole, rotigotine -> risk of fibrotic reactions (ECG to check)
Pramipexole, ropinerole -> sleep attacks with sudden onset of drowsiness

Direct action on dopamine receptors

Question 9

What are examples of catechol-o-methyl transferase (COMT) inhibitors?

Answer 9

Entacapone, Tolcapone (after entacapone tried)

Question 10

What are antimuscarinic drugs used for and what are some examples?

Answer 10

Drug induced Parkinsonism

Orphenadrine, procyclidine, trihexyphenidyl (used for symptoms induced by antipsychotics)