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High-alert medicines on the RCSI theory paper

Insulin (units in full, insulin syringes, second check, single-patient pens, high-strength products), IV potassium (storage, 40 mmol/L, 10 mmol/h), methotrexate once weekly, DOACs, apixaban, controlled drugs, digoxin, metformin.

33 multiple-choice questions, each with an explanation and the document it was checked against. Three questions are free; the pass opens the other 30 and every other topic. Wrong answers come back first the next time you practise, and a question counts as mastered after two correct answers in a row.

Sample questions from this topic

Question 1
A patient’s Parkinson’s disease tablets are due at 08:00 but the drug round is running late. Why does the IMSN treat this as urgent?
1. AParkinson’s drugs interact with breakfast and must be given before food
2. BA late dose has to be re-prescribed by the doctor before it can be given
3. CDelayed Parkinson’s medication causes loss of movement control; it heads the time critical list
4. DThe tablets lose potency if given more than an hour after the printed time on the chart
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Answer: C. IMSN Table 1 lists Parkinson’s disease and movement disorder medication first: the consequence of an omitted or delayed dose is loss of movement control (see the IMSN Parkinson’s series 2024). Hospitals should identify patients on time critical medicines on arrival and set a local time frame for giving them.
Source: IMSN: Safety alert, Time Critical Medicines (September 2025), Table 1
Question 2
How does digoxin help a patient with atrial fibrillation or heart failure?
1. AIt removes fluid through the kidneys
2. BIt slows the ventricular rate and makes each beat stronger
3. CIt thins the blood to stop clots forming in the atria
4. DIt widens the coronary arteries to relieve angina
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Answer: B. HPRA SmPC, section 5.1: digoxin increases contractility of the myocardium by direct action (inhibiting the sodium-potassium pump so more calcium is available at contraction), and through increased vagal impulses it slows impulse conduction through the atria and atrioventricular node, so the major beneficial effect is reduction of ventricular rate. It is indicated in chronic cardiac failure with systolic dysfunction, especially with atrial fibrillation (4.1). Doses are reduced in the elderly and in renal impairment, which is why the pulse is checked before a dose.
Source: HPRA Summary of Product Characteristics: Lanoxin 250 microgram tablets (PA1691/001/004), s. 4.1, 4.2 and 5.1
Question 3
Why is concentrated intravenous potassium considered one of the most dangerous medicines in a hospital?
1. AIt corrodes plastic infusion lines and pump cassettes within a few hours
2. BThe ampoules are almost identical in size and colour to those of insulin
3. CRapid or undiluted infusion causes fatal arrhythmia and cardiac arrest, and cannot be reversed
4. DIt causes severe allergic reactions in a large proportion of the patients who receive it, even when diluted
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Answer: C. IMSN IV potassium guideline: concentrated potassium chloride is a recognised high-risk medication; misadministration often cannot be reversed, and it can be deadly when not prepared and administered properly because rapid infusion causes fatal arrhythmia and cardiac arrest. Internationally, deaths have followed ampoules being mistaken for sodium chloride or water for injection (UK NPSA alert 2002), which is why concentrated potassium is kept out of general ward stock.
Source: IMSN: Best practice guideline on intravenous potassium (2020), Background

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High-alert medicines: RCSI aptitude test practice questions

High-alert medicines on the RCSI theory paper

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