Medication Errors Case Studies
This piece is about Medication Error Cases in the UK and US and what lesson you can gain from and apply at work.
Medication errors can have serious, sometimes fatal consequences. They can lead to patient harm, longer hospital stays, and in some cases, death.
These errors often happen due to a combination of factors such as unclear prescriptions, communication failures, storage problems, and staff shortages or distractions.
These errors often occur due to a combination of factors such as poor communication, unclear prescriptions, language barriers, cultural misunderstandings, and system failures. Learning from past mistakes helps healthcare professionals understand how to prevent similar incidents and create safer care environments for all patients.
This document presents 13 real-life medication error case studies from the UK and USA. Each case includes a short summary of what happened, why the error occurred, and key safety lessons.
Where relevant, equality, diversity, and inclusion (EDI) links are highlighted to show how cultural awareness and good communication can reduce risk. These cases are valuable learning tools for anyone working in healthcare, from frontline staff to managers.
📚Relevant Training: Medication Training Course.
13 Medication Error Case Studies (US & UK)
1. Wrong Medication Dispensed Due to Language Miscommunication (USA, 2016)
Source: The Alarming Reality of Medication Error (PubMed, 2016)
What Happened:
A 71-year-old woman received thiothixene (an antipsychotic) instead of amlodipine (for high blood pressure) for three months because a pharmacy misread a prescription. The patient, a non-native English speaker, didn’t understand the medication instructions and suffered tremors and mobility issues.
Why It Happened:
Poor communication between the pharmacist and patient, partly due to language barriers, led to no verification of the medication. The pharmacy didn’t check the prescription properly, and cultural assumptions about patient understanding contributed.
Lessons for Safety:
- Use clear, plain English in prescriptions and patient instructions.
- Train staff in cultural competence to recognise language barriers and use interpreters.
- Implement medication reconciliation to check prescriptions with patients.
📚Related Article: Common Medication Administration Mistakes and Cost Implications.
2. Insulin Instead of Influenza Vaccine (USA, 2016)
Source: People Magazine (2019)
What Happened:
A nurse accidentally gave insulin instead of the flu vaccine to several patients, causing low blood sugar and hospitalisation for two. The vials were stored together in a refrigerator, and the nurse relied on familiar vial shapes without checking labels.
Why It Happened:
Confirmation bias (assuming the vial was correct) and poor storage practices caused the mix-up. The nurse didn’t involve patients in verifying the medication, missing a chance to catch the error.
Lessons for Safety:
- Store medications separately with clear labels.
- Use barcode scanning to verify medications before administration.
- Encourage patients to ask questions about their treatment, as promoted by WHO’s “Know. Check. Ask.” campaign.
3. Wrong Drug Administered During Procedure (UK, 2004)
Source: Classic Cases Revisited – Death of a Nurse (PubMed, 2014)
What Happened:
Mayra Cabrera, a 30-year-old nurse, died after receiving a wrong-route drug (bupivacaine, an anaesthetic) instead of saline during childbirth. The error occurred in a busy hospital with staff shortages.
Why It Happened:
The error was due to a mix-up in drug storage and poor communication among staff under pressure. Cultural factors, like hierarchical team dynamics, prevented junior staff from questioning the error.
Lessons for Safety:
- Store high-risk drugs separately and use clear labelling.
- Train teams to communicate openly, regardless of rank.
- Use checklists to verify drugs before administration.
📚Get Trained: Medication Administration Training / Communication and Recording Keeping Training in Healthcare.
4. Overdose from Automated Dispensing Error (USA, 2018)
Source: PSNet Case Study (2018)
What Happened:
A child with burns received nearly five times the correct dose of oxycodone (painkiller) because an automated dispensing machine was stocked with a higher concentration than labelled. The child’s breathing slowed, requiring urgent care.
Why It Happened:
The machine was incorrectly stocked, and the nurse didn’t double-check the dose. The child’s parents, who spoke limited English, weren’t informed about the medication, missing a chance to notice the error.
Lessons for Safety:
- Regularly audit automated dispensing machines for accuracy.
- Train staff to verify doses manually, even with technology.
- Use interpreters to explain medications to patients and families.
5. Pharmacy Compounding Error (USA, 2022)
Source: Virginia Mason Institute Case Study (2022)
What Happened:
A patient received etoposide (a chemotherapy drug) instead of infliximab (for arthritis) due to a pharmacy mixing error. The patient suffered side effects like weakness and hair loss.
Why It Happened:
The pharmacy batched multiple medications, leading to a mix-up. Staff didn’t involve the patient in verifying the infusion, and a fast-tracked process skipped safety checks.
Lessons for Safety:
- Prepare medications one at a time to avoid batching errors.
- Use a “stop the line” approach if errors are suspected.
- Engage patients in safety by explaining treatments clearly.
6. Wrong Drug Administered During Childbirth (UK, 2004)
Source: Classic Cases Revisited – Death of a Nurse (PubMed, 2014)
What Happened:
Mayra Cabrera, a 30-year-old nurse at Great Western Hospital, Swindon, died after being given bupivacaine (an anaesthetic) instead of saline during childbirth. The error caused a cardiac arrest.
Why It Happened:
The drug was stored incorrectly, and a busy, understaffed ward led to rushed checks. Cultural and hierarchical issues in the team meant junior staff didn’t challenge the senior midwife’s mistake.
Lessons for Safety:
- Store high-risk drugs separately with clear labels.
- Train staff to communicate openly, regardless of job role or background.
- Use checklists to verify drugs before giving them.
7. Insulin Overdose Due to Miscommunication (UK, 2010)
Source: National Patient Safety Agency (NPSA) Report (2010)
What Happened:
A patient with diabetes at a London hospital received ten times the correct dose of insulin, leading to severe low blood sugar and a coma. The patient recovered after emergency treatment.
Why It Happened:
A nurse misread the prescription due to poor handwriting and didn’t confirm the dose with the patient, who spoke limited English. Cultural assumptions about the patient’s ability to understand instructions led to no interpreter being used.
Lessons for Safety:
- Use clear, typed prescriptions to avoid errors.
- Always confirm doses with patients or their families, using interpreters if needed.
- Train staff to double-check high-risk medications like insulin.
8. Wrong Medication Given in Care Home (UK, 2016)
Source: Care Quality Commission (CQC) Investigation (2016)
What Happened:
An elderly resident in a Manchester care home was given another resident’s medication (a heart drug) instead of her own painkiller, causing a drop in blood pressure and hospitalisation. The resident recovered.
Why It Happened:
Staff mixed up medication charts due to similar patient names and didn’t verify the resident’s identity. The resident, who had dementia and spoke a regional dialect, couldn’t clarify her medication, and staff didn’t seek family input.
Lessons for Safety:
- Use photo ID or wristbands to confirm patient identity.
- Train staff to involve families when patients have communication challenges.
- Implement medication double-checks before administration.
9. Chemotherapy Error Due to Staff Miscommunication (UK, 2008)
Source: NHS Improvement Case Study (2008)
What Happened:
A cancer patient at a Birmingham hospital received an incorrect chemotherapy dose, causing severe side effects like nausea and hair loss. The patient survived but needed extra treatment.
Why It Happened:
A new staff member, from a diverse cultural background, miscommunicated the dose to the pharmacist due to fear of questioning a senior doctor’s unclear instructions. Hierarchical team dynamics and lack of cultural awareness prevented open discussion.
Lessons for Safety:
- Encourage all staff to clarify unclear instructions, regardless of seniority.
- Use electronic prescribing systems to reduce human error.
- Train teams to foster open, inclusive communication.
📌Related Course: Equality, Diversity and Inclusion Training for Healthcare Team.
10. Wrong Dose of Anticoagulant in Hospital (UK, 2015)
Source: NHS England Patient Safety Alert (2015)
What Happened:
A 65-year-old patient at a Leeds hospital was given a double dose of warfarin (a blood thinner), leading to severe internal bleeding and a week-long hospital stay. The patient survived but needed blood transfusions.
Why It Happened:
A nurse misread the dose on a handwritten chart, and the patient, who had limited English proficiency, wasn’t asked to confirm the medication. The ward was short-staffed, and no interpreter was used due to assumptions about the patient’s understanding.
Lessons for Safety:
- Use electronic prescribing to avoid handwritten errors.
- Train staff to use interpreters for patients with language barriers.
- Implement a two-person check for high-risk drugs like warfarin.
11. Allergic Reaction from Unchecked Medication (UK, 2017)
Source: Healthcare Safety Investigation Branch (HSIB) Report (2017)
What Happened:
A 42-year-old patient in a Bristol hospital received penicillin, despite a known allergy recorded in their notes, causing a severe allergic reaction (anaphylaxis). The patient recovered after emergency treatment.
Why It Happened:
A junior doctor, new to the UK and unfamiliar with local protocols, didn’t check the patient’s allergy history due to time pressure and fear of questioning the consultant’s prescription.
The patient, from a minority ethnic background, didn’t feel comfortable raising concerns due to cultural norms around authority.
Lessons for Safety:
- Train all staff, especially new or international workers, on allergy-checking protocols.
- Use electronic alerts to flag allergies before prescribing.
- Encourage patients to share their medical history through clear, inclusive communication.
12. Morphine Overdose in Palliative Care (UK, 2013)
Source: NPSA Rapid Response Report (2013)
What Happened:
An 80-year-old patient in a hospice in Manchester received a morphine dose five times higher than prescribed, leading to respiratory failure and death. The error occurred during a night shift.
Why It Happened:
A nurse miscalculated the dose due to unclear labelling on the syringe pump and didn’t consult the patient’s family, who were present but not fluent in English.
Hierarchical team dynamics discouraged the nurse from seeking a second opinion from the on-call doctor.
Lessons for Safety:
- Use pre-filled syringes or clear dose calculators for high-risk drugs like morphine.
- Train staff to involve families in care decisions, using interpreters if needed.
- Foster a team culture where questioning errors is encouraged.
13. Wrong Patient Given Medication in GP Surgery (UK, 2019)
Source: General Medical Council (GMC) Case Review
What Happened:
A patient at a GP surgery in Birmingham was given another patient’s antidepressant instead of their blood pressure medication, causing dizziness and a fall.
The patient, an elderly woman with hearing difficulties, recovered after hospital treatment.
Why It Happened:
The receptionist called the wrong patient’s name, and the nurse didn’t verify identity due to a busy clinic.
The patient’s hearing impairment wasn’t noted, and no adjustments (like written instructions) were made to ensure understanding.
Lessons for Safety:
- Verify patient identity using two identifiers (e.g., name and date of birth).
- Train staff to accommodate disabilities, such as hearing loss, with clear communication.
- Slow down processes during busy periods to prioritise safety.
Conclusion
These case studies show that medication errors often stem from issues like miscommunication, poor labelling, failure to double-check, or assumptions made under time pressure.
Whether in hospitals, care homes, or GP surgeries, consistent safety practices make a difference.
By learning from these real events, healthcare staff can reduce risks through actions such as:
Using clear and typed prescriptions
Storing medications safely with clear labels
Verifying patient identity and doses before administration
Encouraging open team communication and double-checking in high-risk situations
Involving patients and families in understanding treatment, when possible
A proactive approach to patient safety protects lives and strengthens healthcare systems overall.
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