51 - 55 SBAs for the Final FRCA
Question 51
A patient with Parkinson’s disease has had an elective shoulder replacement under general anaesthesia with an interscalene block.
Postoperatively he feels nauseated, and his Parkinson's medications have been restarted appropriately after the procedure.
Which of the following is most appropriate?
- Metoclopramide
- Domperidone
- Droperidol
- Olanzapine
- Prochlorperazine
Answer
- Domperidone
These drugs all do stuff to dopamine, which is clearly going to give us problems in a patient with Parkinson's.
The real correct answer is to use something that doesn't mess with dopamine in the first place - like cyclizine or ondansetron - but within the confines of this frustrating question your best option is a small dose of domperidone, because it doesn't cross the blood-brain barrier.
It's only available orally because apparently the IV concoction makes people go into cardiac arrest.
Prochlorperazine, metoclopramide and droperidol can all make Parkinsonism worse, and olanzapine isn't first line as an antiemetic here.
A Quick Recap:
- Parkinson's = rigidity, tremor and bradykinesia
- 3% of the population over 66 years old
- Death of dopaminergic cells in substantia nigra in basal ganglia
- They can have a stiff chest, dysautonomia and drug-induced hypotension
- The drugs they take increase the risk of arrhythmias
- Higher incidence of postop cognitive dysfunction and delirium
- Try and avoid drugs that mess with central dopamine or acetylcholine activity where possible