20 Types of Medication Errors in Healthcare: Recognition, Examples and Prevention
Every year, medication errors affect thousands of patients across the UK’s healthcare system. These preventable incidents not only compromise patient safety but also place immense strain on the NHS, costing an estimated £98.5 million annually. Behind each statistic lies a real person whose wellbeing was put at risk. This article examines the 20 most common types of medication errors, explaining each type, providing real-world examples, and offering prevention strategies to help healthcare professionals, patients, and carers avoid these potentially dangerous mistakes.
1. Wrong Patient Error
What it is: This happens when medicine meant for one patient is given to someone else by mistake. It often happens in busy places like hospitals.
Example: A nurse gave antibiotics to Mr Johnson in bed 5, thinking he was Mr Jenkins. Another nurse noticed the mistake soon after.
How to prevent it:
Use barcode scanners to check patient wristbands
Always check two things, like name and date of birth
Ask the patient to say their name
Don’t use bed number or room alone to identify someone
2. Wrong Drug Error
What it is: This happens when the wrong medicine is given, often because the names or packaging look alike.
Example: A pharmacist gave methotrexate instead of metformin because their names looked similar. The mistake was caught during the final check.
How to prevent it:
Use tall-man letters to make names stand out (e.g. hydrOXYzine vs hydrALAzine)
Keep similar-looking medicines in different places
Use electronic systems with alerts
Always double-check the medicine with the prescription
3. Wrong Dose Error
What it is: This means giving too much or too little of the right medicine, which can be harmful.
Example: A doctor wrote 5000mg of amoxicillin instead of 500mg. A pharmacist noticed the high dose and checked with the doctor.
How to prevent it:
Use systems that check the correct dose
Watch out for decimal points and conversions
Double-check high-risk medicine doses
Ask someone else to check your calculations if needed
4. Wrong Route Error
What it is: This happens when medicine is given the wrong way, like giving tablets by injection.
Example: A care worker gave ear drops by mouth because they misunderstood the instructions in poor lighting.
How to prevent it:
Label medicines clearly with how they should be given
Use colour codes for different types (oral, injection, etc.)
Make sure lighting is good
Train staff to know the right way to give medicines
5. Wrong Time Error
What it is: This means giving medicine at the wrong time, which can make it less effective or harmful.
Example: A Parkinson’s patient got their medicine three hours late, causing movement problems.
How to prevent it:
Use systems with time alerts
Focus on important medicines during busy times
Have clear timing plans for staff
Make sure there are enough staff to avoid delays
6. Wrong Formulation Error
What it is: This is when the right medicine is given in the wrong form, like giving tablets instead of liquid.
Example: A patient who couldn’t swallow got capsules instead of orodispersible tablets.
How to prevent it:
Write clearly on prescriptions if a special form is needed
Check if the patient can use the medicine form
Make sure pharmacy staff know about different versions
Confirm the form before giving or dispensing
7. Omission Error
What it is: This happens when a dose of medicine is missed or not given.
Example: A patient after surgery missed two doses of blood thinners, leading to a blood clot.
How to prevent it:
Use systems that show missed doses
Have clear handovers between shifts
Use checklists for medicine
Have a plan for when medicine is not available
8. Allergy Error
What it is: This means giving medicine to someone who is allergic to it.
Example: A patient allergic to penicillin was given amoxicillin and had a serious reaction.
How to prevent it:
Use clear allergy warnings in records
Use red allergy wristbands for hospital patients
Always check allergies before giving medicine
Train staff about allergy risks and related drugs
9. Wrong Patient Preparation Error
What it is: This happens when a patient is not ready for the medicine, like not fasting when they should.
Example: A patient didn’t prepare properly for a colonoscopy and had to reschedule.
How to prevent it:
Give clear written instructions
Use standard steps for preparation
Call patients to check they understand
Train staff to check preparation before giving medicine
10. Dispensing Error
What it is: This means the pharmacy gives the wrong medicine, strength, or amount.
Example: A patient was given atorvastatin instead of amlodipine, which caused high blood pressure.
How to prevent it:
Use double-checks during dispensing
Use barcode scanners
Keep pharmacy workloads manageable
Store look-alike drugs in separate places
11. Monitoring Error
What it is: This happens when a patient’s medicine isn’t checked properly, especially for drugs that need regular blood tests or close watching.
Example: A patient on warfarin missed blood tests for three weeks. No one followed up, and the patient had internal bleeding.
How to prevent it:
Set up reminder systems for check-ups
Make clear rules for checking certain medicines
Use electronic alerts for missed tests
Give one staff member the job of following up
12. Unauthorised Drug Error
What it is: This is when medicine is given without a prescription or by someone who isn’t allowed to give it.
Example: A healthcare assistant gave a strong painkiller without a prescription, skipping safety checks.
How to prevent it:
Make clear who can give each type of medicine
Keep strong or risky medicines locked away
Check medicine records regularly
Have clear steps to follow in urgent cases
13. Documentation Error
What it is: This happens when medicine records are wrong or incomplete—for example, signing for a dose that wasn’t given.
Example: A nurse signed that she gave antibiotics but got distracted and forgot. The next staff member thought it was done and skipped the dose.
How to prevent it:
Only sign after giving the medicine
Use electronic systems to record medicine use
Keep medicine areas free from distractions
Do regular checks of the records
14. Communication Error
What it is: This is when information about medicine is not shared properly between staff or with patients.
Example: A hospital didn’t tell the patient’s GP about a medicine change. The patient took both the old and new medicine and had very low blood pressure.
How to prevent it:
Use clear, standard forms for handovers
Try communication tools like SBAR (Situation, Background, Assessment, Recommendation)
Give written medicine details to patients
Review all medicines when patients move between care settings
15. Storage Error
What it is: This happens when medicine is stored the wrong way, which can make it not work or even be unsafe.
Example: Insulin was left on a shelf instead of in the fridge. It went bad and didn’t control patients’ blood sugar properly.
How to prevent it:
Label how each medicine should be stored
Check fridge temperatures regularly
Keep different types of medicines in separate places
Train staff on proper storage
16. Labelling Error
What it is: This means the label on the medicine is wrong or missing important details.
Example: Eye drops were labelled without saying “for external use only”, so the patient swallowed them by mistake.
How to prevent it:
Use standard label formats
Use machines to print clear labels
Always have a second person check labels
Use simple, clear language for patients
17. Prescription Error
What it is: This happens when a doctor writes the wrong medicine, dose, or how often to take it.
Example: A doctor gave a sleep medicine to a patient already on other calming medicines, which made the patient too sleepy and they fell.
How to prevent it:
Use electronic prescribing with safety checks
Review medicines regularly, especially if a patient takes many
Teach doctors about risky medicines
Have pharmacists check complex prescriptions
18. Compounding Error
What it is: This happens when medicine is mixed or prepared incorrectly before being given.
Example: A chemotherapy drug was made too strong, and the patient got double the dose.
How to prevent it:
Use standard forms for mixing medicine
Always have two people check calculations
Train staff in safe mixing techniques
Use ready-made products when possible
19. Technology-Related Error
What it is: This means a mistake happened because of problems with machines or software used to manage medicine.
Example: A nurse set a drip pump to give 55ml per hour instead of 5.5ml, which made the patient’s blood pressure drop too fast.
How to prevent it:
Train staff properly on all devices
Use “smart” pumps that stop wrong doses
Check staff skills often
Make machines simple and easy to use
20. Patient Education Error
What it is: This happens when patients don’t get the right advice about their medicine, leading to mistakes at home.
Example: An older patient left hospital with lots of new medicines but wasn’t told how to use them properly. She took too much of some and missed others.
How to prevent it:
Give easy-to-read instructions
Use the “teach-back” method to check understanding
Have a pharmacist explain medicines before discharge
Call patients after big medicine changes to check they’re okay
Why this matters
By knowing about these common medication errors, healthcare staff can take simple steps to keep patients safe. It’s important to have a safety culture—where people feel safe to report mistakes without being blamed. This helps everyone learn and improve. When staff report problems through the National Reporting and Learning System (NRLS), it helps the NHS spot patterns and make national changes to stop the same mistakes happening again.
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