Parkinson's disease

Question 1

What is the cause of parkinson’s disease?

Answer 1

Loss of dopaminergic neurones in nigrostriatal pathway

Question 2

What are the symptoms of parkinson’s disease

Answer 2

MOTOR
- Tremor
- Hypokinesia
- Bradykinesia
- Rigidity (Inform DVLA)

NON-MOTOR
- Dementia
- Depression
- Sleep problems
- Weight loss

Question 3

What are the treatments for parkinson’s disease?

Answer 3

Affect quality of life?
Yes: First line: levodopa
No:
- Levodopa
- MAO-B inhibitor
- Dopamine receptor agonist (non-ergot)

+ Motor complications
- Dopamine receptor agonist (non-ergot) - Ergot derived not recommended due to side effects
- MAO-B inhibitor
- COMT inhibitor

Don’t stop abruptly: Neuroleptic malignant syndrome + acute akinesia

Nausea + vomiting: domperidone

Question 4

What is the MOA of dopaminergic drugs?

Answer 4

• INC dopamine, prevent breakdown or act on dopamine receptor
• Counsel: report addiction like symptoms

Question 5

What is the MOA of levodopa and give examples

Answer 5

INC dopamine levels

Take w peripheral dopa-decarboxylase inhibitors = RED dose + s/e

• Co-beneldopa
• Co-careldopa

Question 6

What is the indication of levodopa?

Answer 6

First line: parkinson’s disease (if QoL affected)

Question 7

What are the side effects levodopa?

Answer 7

Impulse control disorders (gambling, hypersexuality)

Sudden onset of sleep

Motor complications
- Dyskinesia, motor fluctuations: ON-OFF + end of dose deterioration (Long acting preparations may help)
- Counselling: take at specific times

Question 8

What is the MOA of dopamine receptor agonist?

Answer 8

Stimulate post synaptic D2 receptors

Question 9

Give examples of dopamine receptor agonist

Answer 9

Apomorphine (potent, QT prolongation)

Ergot derived: Bromocriptine (suppress lactation)

Non-ergot:
- Pramipexole
- Rotigotine
- Ropinirole

Question 10

What is the indication of dopamine receptor agonist?

Answer 10

First line: parkinson’s disease (if QoL NOT affected)

Question 11

What are the side effects of dopamine receptor agonist?

Answer 11

• Impulse control disorders (gambling, hypersexuality)
• Sudden onset of sleep
• Driving
• Psychotic symptoms (hallucinations
• Hypotensive reaction (Driving)

Question 12

What is the MOA of MAO-B inhibitor? and give examples

Answer 12

Blocks monoamine oxidase B = prevent central dopamine breakdown

• Selegiline (driving - metabolises amfetamines)
• Rasagiline

Question 13

What is the indication for MAO-B inhibitors?

Answer 13

First line: parkinson’s disease (if QoL NOT affected)

Question 14

What are the interactions of MAO-B inhibitors?

Answer 14

Serotonergic drugs (Antidepressants, methadone, tramadol, St John’s Wort, sumatriptan) → Serotonin syndrome

Sympathomimetics (OTC decongestants, Adrenaline, noradrenaline, Amfetamines + methylphenidate, Beta2 agonist → hypertensive crises

Question 15

What are the MOA of COMT inhibitors and give examples

Answer 15

• Blocks catechol-o-methyltranserase; prevents peripheral levodopa breakdown
• Prevents central dopamine break down (tolcapone)
• Entacapone (colours urine)
• Tolcapone (hepatotoxic)

Question 16

What is the indication of COMT inhibitors?

Answer 16

Parkinson’s disease (levodopa adjunct)

Question 17

What are the side effects of COMT inhibitors?

Answer 17

Red-brown urine (entacapone)
- Counsel: colours urine

Hepatotoxicity (tolcapone)
- Counsel: report signs of liver disorder (Persistent vomiting, abdominal pain, dark urine, jaundice)

Question 18

What is the interaction of COMT inhibitors?

Answer 18

Sympathomimetics (adrenaline, noradrenaline, dopamine) → INC cardiovascular effects