Medication Error Case Studies, Safety Lessons and Prevention Strategies

Medication error cases in the UK and USA highlight a severe, systemic threat to public health, contributing to thousands of avoidable injuries and deaths each year.

Despite different healthcare models—the NHS and the USA’s multi‑payer system—both countries face similar challenges: communication breakdowns, high clinical workloads, and look‑alike/sound‑alike drug mix‑ups.

These shared risks drive strong emphasis on incident reporting, learning and improved clinical governance.

Medication errors are a type of Patient Safety Incident (PSI) involving mistakes in the prescribing, preparing, dispensing, administering, monitoring, or providing advice on medicines.

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Famous Medication Error Case Studies

UK Case Studies

1. Wayne Jowett Case (2001)

Wayne Jowett, an 18‑year‑old patient, died after vincristine was mistakenly administered into the spinal fluid instead of intravenously. The case exposed major weaknesses in chemotherapy safety, medication procedures and system controls. This is one of the major medication error case study discussed in our medication administration course.

2. Bawa‑Garba / Jack Adcock Case (2011)

Six‑year‑old Jack Adcock died following multiple clinical failures, including delayed treatment, missed observations and communication breakdowns. The case became a key example of human factors, system pressures and professional accountability in UK healthcare.

3. Gosport War Memorial Hospital Case (1989–2000)

An independent investigation found that inappropriate prescribing and administration of opioid medicines shortened the lives of hundreds of patients. The case highlighted serious failures in prescribing, monitoring, governance and organisational oversight.

US Case Studies

1. Betsy Lehman Case (1994)

Betsy Lehman died after receiving a chemotherapy overdose at Dana‑Farber Cancer Institute. The case revealed failures in dosing, communication and checking systems, prompting significant improvements in chemotherapy safety.

2. Charles Cullen Case (1988–2003)

Nurse Charles Cullen deliberately administered lethal medicines to patients across several US hospitals. The case exposed critical weaknesses in staff monitoring, information sharing and organisational safeguards. This is also one of the examples of medication errors discussed in nursing schools.

3. Josie King Case (2001)

Eighteen‑month‑old Josie King died following infection‑related complications and failures to respond to her deteriorating condition. Her case became highly influential in patient‑safety education, particularly around communication, escalation and listening to patients and families.

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.

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.

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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.

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.

Medication Error Prevention Strategies

Effective medication‑error prevention relies on strong systems, human‑factors awareness and consistent safe practice. Key strategies include:

Robust systems and processes — Standardised procedures, clear responsibilities and well‑designed workflows reduce opportunities for mistakes.
Safer medicine selection and handling — Clear labelling, organised storage and reducing look‑alike/sound‑alike (LASA) risks help prevent mis‑selection.
Optimised working environments — Good lighting, reduced noise, organised clinical areas and minimal interruptions support safer dispensing and administration.
Strong staff training and human‑factors awareness — Ongoing education on safe practice, fatigue, workload pressure and interruption management is essential.
Effective reporting and learning systems — Transparent incident reporting, root‑cause analysis and shared learning help prevent recurrence and strengthen governance.
Interprofessional collaboration — Nurses, pharmacists, prescribers and managers must work together to identify risks and reinforce safety barriers.
Focus on high‑risk areas — High‑risk medicines, polypharmacy and transitions of care require targeted interventions, as highlighted by WHO.
Patient and family involvement — Encouraging questions, clarifying instructions and using tools like WHO’s 5 Moments for Medication Safety improves safe medicine use.

Conclusion

Medication errors can have serious, sometimes fatal consequences, as shown by case studies from both the UK and the USA. These incidents highlight the need for accurate prescribing, safe administration, clear communication, effective checking systems and strong staff training.

Errors often arise from miscommunication, unclear labelling, failure to double‑check information or assumptions made under time pressure. Whether in hospitals, care homes or GP surgeries, consistent safety practices are essential to reducing these risks.

Healthcare staff can improve medication safety by:

Using clear, accurate prescriptions
Storing medicines safely with clear labels
Checking the patient’s identity, medicine and dose before administration
Encouraging open communication and double‑checking high‑risk medicines
Involving patients and families in understanding their treatment where appropriate

The key lesson is that medication safety is not only about individual mistakes. Strong systems, clear procedures, good teamwork and a culture of reporting and learning are vital to reducing errors and protecting patients.

By learning from previous incidents and taking a proactive approach to patient safety, healthcare organisations can strengthen practice, reduce avoidable harm and deliver safer, higher‑quality care.