PSA Cardiovascular Prescribing 2 — Questions and Answers
Question 1: A 68-year-old man with newly diagnosed HFrEF (EF 30%) is started on ramipril 1.25mg twice daily. Which monitoring is essential 1–2 weeks after initiation?
- Full blood count and liver function tests
- Urea, electrolytes, and creatinine (Correct answer)
- Thyroid function tests
- Blood glucose and HbA1c
Correct answer: Urea, electrolytes, and creatinine
ACE inhibitors can cause acute kidney injury and hyperkalaemia; urea, electrolytes, and creatinine must be checked within 1–2 weeks of starting.
Question 2: A 65-year-old man on bisoprolol 5mg daily for HFrEF develops an acute COPD exacerbation requiring nebulised salbutamol. What is the most appropriate action regarding bisoprolol?
- Stop bisoprolol immediately
- Switch to a non-selective beta-blocker
- Continue bisoprolol unless haemodynamically unstable (Correct answer)
- Double the dose to protect the heart during the acute illness
Correct answer: Continue bisoprolol unless haemodynamically unstable
Cardioselective beta-blockers should not be stopped abruptly in heart failure even during COPD exacerbations, as abrupt withdrawal risks acute decompensation.
Question 3: A patient with systolic heart failure on furosemide 80mg daily has a potassium of 3.0 mmol/L and is also prescribed digoxin. Why is this particularly dangerous?
- Furosemide decreases digoxin clearance
- Hypokalaemia sensitises the myocardium to digoxin toxicity (Correct answer)
- Furosemide and digoxin compete for renal tubular transport
- Both drugs synergistically prolong the QT interval
Correct answer: Hypokalaemia sensitises the myocardium to digoxin toxicity
Hypokalaemia increases myocardial sensitivity to digoxin, raising the risk of life-threatening arrhythmias even at therapeutic digoxin levels.
Question 4: A 77-year-old man with HFrEF is considered for spironolactone 25mg daily. His eGFR is 26 mL/min. What is the primary prescribing concern?
- Spironolactone will be ineffective below eGFR 30
- Severe hyperkalaemia risk due to reduced renal potassium excretion (Correct answer)
- High risk of gynaecomastia in elderly men
- Spironolactone causes metabolic alkalosis in renal impairment
Correct answer: Severe hyperkalaemia risk due to reduced renal potassium excretion
Spironolactone is generally avoided when eGFR < 30 mL/min because impaired renal potassium excretion combined with aldosterone antagonism markedly increases hyperkalaemia risk.
Question 5: A 60-year-old woman with heart failure and AF on warfarin (INR 2–3) is started on amiodarone. What interaction should be anticipated?
- Amiodarone reduces warfarin effect, requiring dose increase
- Amiodarone inhibits CYP2C9, increasing warfarin levels and bleeding risk (Correct answer)
- Amiodarone induces CYP3A4, accelerating warfarin metabolism
- There is no clinically significant interaction
Correct answer: Amiodarone inhibits CYP2C9, increasing warfarin levels and bleeding risk
Amiodarone potently inhibits CYP2C9, the enzyme responsible for S-warfarin metabolism, causing significantly elevated INR and increased haemorrhage risk.
Question 6: A patient with HFrEF previously on ramipril is being switched to sacubitril/valsartan. What is the minimum washout period required after stopping ramipril?
- 6 hours
- 12 hours
- 24 hours
- 36 hours (Correct answer)
Correct answer: 36 hours
A 36-hour washout after stopping an ACE inhibitor is required before starting sacubitril/valsartan to minimise the risk of angioedema from combined bradykinin accumulation.
Question 7: A 74-year-old man with HFrEF has a BP of 88/60 mmHg at clinic. He is on ramipril 10mg, bisoprolol 10mg, furosemide 80mg, and spironolactone 25mg daily. Which medication should be reduced first?
- Ramipril
- Bisoprolol
- Furosemide (Correct answer)
- Spironolactone
Correct answer: Furosemide
In symptomatic hypotension in HFrEF, the diuretic is typically reduced first as it contributes to low filling pressures without direct survival benefit.
PSA Cardiovascular Prescribing 2
A 68-year-old man with newly diagnosed HFrEF (EF 30%) is started on ramipril 1.25mg twice daily.
Which monitoring is essential 1–2 weeks after initiation?