Post-Operative Nausea and Vomiting Flashcards
How is Dexamethasone used to treat PONV?
4-8mg prior to anaesthesia can prevent PONV. Also effective against late-onset PONV.
Dopamine antagonists used for PONV
Droperidol and Metoclopramide
What drug class does Droperidole belong to?
Dopamine antagonists.
How are 5HT3 antagonists used for PONV?
Given at the end of surgery. More effective against vomiting than nausea.
Opioid analgesics used for PONV
Morphine sulphate
Tramadol
Antihistamine used for nausea and vomiting. How is it used?
Promethazine, used prophylactically.
What is Droperidole used for in PONV?
Effective at preventing onset of PONV. Not used to treat pre-existing Nausea and vomiting.
What are two examples of 5HT3 antagonists used to treat PONV?
Ondansetron
Tropisetron
When would you use Ondansetron?
Given at the end of surgery to prevent post-operative vomiting.
What is one reason for not prescribing NSAIDs for post-operative pain?
Pre-operative renal impairment. e.g. creatinine elevated.
Why wouldn’t you prescribe Pethidine?
Pethidine use is strongly discouraged because of its short duration of action, accumulation of the toxic metabolite norpethidine which may result in seizures, and its high propensity for inducing drug seeking behaviour.
Why wouldn’t you use metoclopramide or droperidol to treat a patient with parkinson’s disease?
Because they both block dopamine receptors. Reduced dopamine levels is involved in the pathogenesis of Parkinson’s disease.
In which cohort of patients is codeine ineffective?
Codeine is converted to morphine by CYP2D6 and has little or no analgesic activity on it’s own, so it will be ineffective in CYP2D6 ‘poor metaboliser’ patients.
