RACP-Pharm

Question 1

A 40-year-old Ethiopian lady is admitted with pneumonia and pleuritic chest pain. She is commenced on Paracetamol 1g QID and Codeine 60 mg QID. The next day she is found to be drowsy and her respiratory rate is 8. You suspect that she is narcotised, and you administer Naloxone to which she responds well.
What is the cause of her presentation?
a) She is a fast CYP metaboliser
b) Accidental administration of Morphine
c) Accidental administration of higher doses of Codeine
d) Concurrent use of Paracetamol
e) Covert use of Endone

Answer 1

A- She is a fast CYP metaboliser

• Codeine is a prodrug that is metabolized by the CYP2D6 enzyme into morphine, which is responsible for its analgesic effects.
• Individuals with ultrarapid CYP2D6 metabolism convert codeine to morphine at a much higher rate, leading to elevated morphine levels and increased risk of opioid toxicity (e.g., respiratory depression)

Question 2

Which is the following if co-administered with Dabigatran will likely to lead to a rise in the serum concentrations of Dabigatran?
a) Itraconazole
b) Adenosine
c) Verapamil
d) Metoprolol
e) Paroxetine

Answer 2

A) Itraconazole

Dabigatran is a substrate of p-glycoprotein

both itraconazole and verapamil are inhibitors which would therefore result in an increase in the serum concentration of dabigatran

itraconazole more than verapamil

Question 3

Which of following medications decreases the effect of Tamoxifen in hormone positive Breast Cancer?
a) Paroxetine
b) Warfarin
c) Verapamil
d) Carbamazepine
e) Alcohol

Answer 3

A) paroxetine