Prescribing Error Exercise
Spot the Mistakes

Mr Alan Park · 58 · Suspected ACS · Acute Admission Drug Chart

6 errors hidden Y1 / Y2 Cardiology ACS management
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How to use this exercise

The drug chart below contains 6 deliberate prescribing errors. Each error is marked with a red ? badge. Click any highlighted cell to reveal the error and the correct prescription.

Try to spot all 6 yourself before using “Reveal All”. The full answer key is below the chart.

Errors found
0 / 6
Error types
Wrong dose
Wrong route
Contraindicated
Omission
Admin error
Northbridge General Hospital NHS Trust
Acute Inpatient Medication Administration Record
Chart No: 3
Ward: Cardiology AMU
SurnamePARK
First nameAlan
Date of birth 14 / 03 / 1974 ?
⚠ Error 6 — Wrong Patient DOB
DOB recorded as 1974, making the patient 50. Mr Park is 58, born 1966.
Correct: 14 / 03 / 1966. Always verify using two identifiers before prescribing.
Hospital No.NB-447821
Weight88 kg
ConsultantDr S. Mehta
Date of admission09/07/2025
Diagnosis? NSTEMI / ACS
⚠ Allergies & Adverse Reactions Not completed ? UNSIGNED
⚠ Error 5 — Allergy Box Not Completed
Left blank and unsigned. No medication can be safely administered without documented allergy status.
Correct: Write “NKDA” if confirmed, or list specific allergies. Must be signed and dated by the prescriber.
# Drug (approved name) Dose Route Frequency Start date Indication Prescriber & GMC Notes
1 ASPIRIN 75 mg ?
⚠ Error 1 — Wrong Dose
75mg is the maintenance dose. ACS requires a 300mg loading dose to achieve rapid platelet inhibition.
Correct: Aspirin 300mg STAT (chewed), then 75mg OD.
 PO STAT then OD 09/07/25 ACS antiplatelet Dr T. Rees
GMC: 7823441 		Chew and swallow
2 GLYCERYL TRINITRATE (GTN) SPRAY 400 mcg
(1 spray) 		PO ?
⚠ Error 2 — Wrong Route
GTN oral = first-pass metabolism destroys it. Must be given sublingually for mucosal absorption.
Correct: Route = SL (sublingual). Spray under the tongue.
 PRN — max 3 doses, 5 min apart 09/07/25 Angina / chest pain Dr T. Rees
GMC: 7823441 		Call Dr if no relief after 3rd dose
3 MORPHINE SULFATE IV 10 mg IV PRN ?
⚠ Error 3 — Incomplete CD Prescribing
Morphine (Schedule 2 CD) prescribed without maximum dose, minimum interval, or 24-hour limit. Unsafe for nurses to administer.
Correct: Morphine 2–5mg IV PRN, max every 4 hours, max 20mg/24h. Co-prescribe antiemetic (e.g. metoclopramide 10mg IV PRN).
 09/07/25 Analgesia — chest pain Dr T. Rees
GMC: 7823441
4 IBUPROFEN ?
⚠ Error 4 — Contraindicated Drug
NSAIDs are contraindicated in ACS. Ibuprofen increases CV risk, competes with aspirin at COX-1, causes fluid retention, and raises bleeding risk alongside anticoagulation.
Correct: Remove entirely. Use paracetamol 1g QDS PO for background analgesia instead.
 400 mg PO TDS 09/07/25 Analgesia Dr T. Rees
GMC: 7823441 		With food
5 ATORVASTATIN 80 mg PO OD (nocte) 09/07/25 ACS — high intensity statin Dr T. Rees
GMC: 7823441 		Take at night
6 OXYGEN Target SpO₂ 94–98% Inhaled Continuous — titrate 09/07/25 Hypoxia if present Dr T. Rees
GMC: 7823441 		Do not give if SpO₂ >94%
7 FONDAPARINUX 2.5 mg SC OD 09/07/25 NSTEMI anticoag Dr T. Rees
GMC: 7823441 		Review renal function
8 TICAGRELOR 180mg load then 90mg PO STAT then BD 09/07/25 ACS dual antiplatelet Dr T. Rees
GMC: 7823441 		With aspirin 75mg OD
9
10
Prescriber signatureT. Rees
Print name & bleepDr T. Rees — Bleep 4421
Date & time signed09/07/2025 — 10:42
🔴 Click any cell with a red ? badge to reveal the error · 6 errors total

Answer Key

6 errors

Click each card to expand the full explanation. Try the chart first.

01 Aspirin — Wrong dose (loading dose missed) Wrong dose ▼
What was prescribed
Aspirin 75mg PO STAT then OD
What it should be
✓ Aspirin 300mg PO STAT (chewed), then 75mg OD as maintenance
In ACS, aspirin irreversibly inhibits platelet thromboxane A₂ production. A 300mg loading dose is needed for rapid, near-complete platelet inhibition. 75mg alone is the ongoing maintenance dose — it is insufficient in the acute setting. The tablet should be chewed for faster absorption.

Common exam trap: candidates confuse the maintenance dose (75mg) with the loading dose (300mg).
⚠ High risk — underdosing in acute MI allows ongoing thrombosis
02 GTN Spray — Wrong route (oral instead of sublingual) Wrong route ▼
What was prescribed
GTN 400mcg spray — Route: PO (oral)
What it should be
✓ GTN 400mcg spray — Route: SL (sublingual)
GTN must be given sublingually — sprayed or placed under the tongue for direct mucosal absorption. If swallowed, it undergoes near-complete first-pass hepatic metabolism and has no therapeutic effect.

Sublingually, GTN acts within 1–3 minutes, causing vasodilation and reducing cardiac preload. The patient should be sitting or lying down due to the hypotension risk.
⚠ Oral GTN is completely ineffective — patient receives no treatment
03 Morphine — Incomplete controlled drug prescribing Omission ▼
What was prescribed
Morphine 10mg IV PRN — no maximum dose, no interval, no 24-hour limit, no antiemetic
What it should be
✓ Morphine 2–5mg IV PRN, max every 4 hours, max 20mg in 24 hours. Co-prescribe metoclopramide 10mg IV PRN (antiemetic).
Morphine is a Schedule 2 controlled drug. Writing only “PRN” with no limits is incomplete and unsafe — nursing staff cannot administer it without clear dosing parameters. Multiple doses could cause respiratory depression.

The 10mg IV dose is also high for a first dose; 2–5mg IV with titration is standard. Opioids consistently cause nausea — an antiemetic must always be co-prescribed.
⚠ Patient safety risk — respiratory depression from uncontrolled opioid dosing
04 Ibuprofen — Contraindicated NSAID in ACS Contraindicated ▼
What was prescribed
Ibuprofen 400mg PO TDS for analgesia
What it should be
✓ Remove entirely. Use paracetamol 1g QDS PO for background analgesia. NSAIDs are absolutely contraindicated in ACS.
NSAIDs are contraindicated in ACS for four reasons:

1. Cardiovascular risk — increase risk of MI, stroke and CV death even short-term
2. Aspirin interaction — ibuprofen competes for the COX-1 binding site, blocking aspirin’s irreversible antiplatelet effect
3. Fluid retention — worsen BP and cardiac workload
4. GI bleeding risk — combined with aspirin and fondaparinux, significantly increases haemorrhage risk
⚠ Critical error — NSAIDs absolutely contraindicated in ACS
05 Allergy box — Not completed or signed Omission ▼
What was written
Allergy section left blank — no entry, unsigned
What it should be
✓ “NKDA” if confirmed with patient, or specific allergies listed. Signed and dated by prescriber before any drug is given.
An unsigned, blank allergy box means it is unknown whether the patient has drug allergies. Nursing staff must not administer any drug until this is completed. The prescriber must ask about allergies (at minimum: penicillin, aspirin, contrast) and document the response. This is consistently flagged by the GMC as a top prescribing error.
⚠ Never administer from a chart with an unsigned allergy box
06 Patient DOB — Incorrect (wrong year recorded) Admin error ▼
What was recorded
DOB: 14 / 03 / 1974 (age 50)
What it should be
✓ DOB: 14 / 03 / 1966 (age 58). Verify using wristband, NHS number, and ask the patient directly.
Incorrect patient identifiers can lead to wrong-patient medication errors. The two-identifier rule requires checking full name + DOB before prescribing or administering. A mismatch between chart and wristband means the nurse must stop and clarify before giving any drug.

An incorrect age also affects risk scores (e.g. GRACE score for ACS) and dosing thresholds.
⚠ Wrong-patient errors are a leading cause of serious harm