Worked Examples: Medication Errors and Near-Misses

Medication errors are among the most commonly tested patient safety topics in the UCAT SJT. The NHS estimates that medication errors contribute to over 700 deaths per year and cost the health service approximately £98.5 million annually. Because of their prevalence and severity, SJT scenario writers return to this topic repeatedly.

This lesson walks through detailed worked examples, showing you how to apply the SAFE framework to medication error scenarios.

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Types of Medication Errors

Before we work through examples, understand the categories of medication errors you may encounter:

Error Type	Description	Example
Prescribing error	Wrong drug, dose, route, or frequency prescribed	Methotrexate prescribed daily instead of weekly
Dispensing error	Pharmacy issues wrong drug or wrong formulation	Liquid paracetamol dispensed instead of tablets for an adult
Administration error	Drug given incorrectly	IV drug given too rapidly
Monitoring error	Required blood tests or observations not done	Warfarin prescribed without INR monitoring
Allergy error	Drug prescribed despite known allergy	Penicillin given to penicillin-allergic patient
Omission error	Prescribed drug not given	Insulin omitted at mealtimes

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Worked Example 1: The Decimal Point Error

Scenario:

You are a medical student on a paediatric ward. You are reviewing the drug chart for 4-year-old Sophie, who weighs 16kg. The FY1 has prescribed morphine 16mg IV for post-operative pain relief. You recall from your pharmacology lectures that the standard paediatric dose of morphine is 0.1mg/kg, which would be 1.6mg for Sophie.

Applying the SAFE Framework:

S — Spot the Risk: The prescribed dose (16mg) is 10 times the calculated correct dose (1.6mg). This is a classic decimal point error. 16mg of IV morphine in a 4-year-old could cause fatal respiratory depression. This is an immediate patient safety risk.

A — Act Appropriately: Act immediately. This drug must NOT be administered at the prescribed dose. You need to prevent its administration and alert the prescriber.

F — Follow the Right Path:

1. If the nurse is about to give the drug, speak up immediately: "Excuse me, I think there might be an issue with this dose — could we double-check it before it's given?"
2. Inform the FY1 who prescribed it: "I've been looking at Sophie's morphine prescription and I think the dose might be 10 times too high. The standard paediatric dose would be 1.6mg for her weight."
3. If the FY1 disagrees or is unavailable, escalate to the registrar immediately.

E — Ensure Follow-Up:

• The prescription must be corrected before any morphine is given
• This near-miss should be reported through the hospital incident reporting system
• The pharmacy should be alerted so they can intercept the order if it has already been sent

SJT Rating of Actions:

Action	Rating	Reasoning
Immediately inform the nurse and the FY1 about the suspected dose error	Very Appropriate	Prevents harm, involves the right people
Calculate the correct dose and present it to the FY1	Appropriate	Helpful, but you should also ensure the current prescription is not given in the meantime
Make a note to discuss it with your clinical supervisor later	Very Inappropriate	Dangerous delay — the drug could be given before then
Assume the FY1 knows more about dosing than you	Very Inappropriate	Patient safety overrides hierarchy; a 10x error is objectively dangerous

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Worked Example 2: The Wrong Patient

Scenario:

You are observing on a medical ward when you see a healthcare assistant (HCA) take a medication pot to Bed 3. The patient in Bed 3 says, "Those aren't my usual tablets — mine are blue, not white." The HCA replies, "The pharmacy sometimes changes the brand. Just take them."

Applying the SAFE Framework:

S — Spot the Risk: The patient has flagged a change in their medication. While it IS true that pharmacies sometimes change brands (resulting in different coloured tablets), the patient's concern could also indicate that they are about to receive the wrong medication. This needs to be verified before the tablets are taken.

A — Act Appropriately: Intervene before the patient takes the tablets. Politely suggest that the medication should be checked.

F — Follow the Right Path:

1. Say to the HCA: "The patient has noticed a change — would it be worth double-checking with the nurse before they take them?"
2. If the HCA insists, you can ask the nurse directly to verify the medication against the prescription chart.
3. You should NOT take the medication pot away yourself or confront the HCA aggressively.

E — Ensure Follow-Up:

• The medication should be checked against the prescription chart and the patient's identity verified (name, date of birth, wristband)
• If it was the wrong medication, report it as a near-miss
• If it was a brand change, the patient should be reassured and the reason explained

SJT Rating of Actions:

Action	Rating	Reasoning
Suggest the medication is checked against the prescription chart before being taken	Very Appropriate	Prevents potential harm, proportionate response
Tell the patient not to take the tablets	Appropriate	Prevents potential harm, but may cause unnecessary alarm
Stay silent because the HCA seems confident	Very Inappropriate	The HCA is not qualified to prescribe; the patient's concern is valid
Take the medication pot away from the HCA	Inappropriate	Confrontational and not your role; involves the right people instead

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Worked Example 3: The Allergy That Was Not Checked

Scenario:

You are sitting in on a GP consultation. The GP prescribes co-amoxiclav (which contains amoxicillin, a penicillin) for a patient with a chest infection. As the patient leaves, they say to you, "I hope this one doesn't make me swell up like last time — I had a terrible reaction to penicillin years ago." The GP has already printed the prescription.

Applying the SAFE Framework:

S — Spot the Risk: The patient has a history of penicillin allergy and has just been prescribed a penicillin-containing antibiotic. If they take this, they could have a serious allergic reaction, potentially anaphylaxis. This is an immediate patient safety risk.