Prescription Writing Errors and How to Catch Them as a Patient

Every year, over 1.5 million people in the U.S. are harmed by mistakes in their prescriptions. Many of these errors happen before the pill even leaves the doctor’s office. You might think your doctor or pharmacist has it covered-but the truth is, prescription writing errors are more common than you realize, and you’re the last line of defense. A wrong dose, a confusing abbreviation, or a mix-up between two similar-sounding drugs can lead to serious harm-or even death. The good news? You don’t have to wait for something to go wrong. With a few simple checks, you can catch these mistakes before they hurt you.

What Are Prescription Writing Errors?

Prescription writing errors are mistakes made by doctors or other providers when they write or enter a medication order. These aren’t pharmacy mistakes-they happen at the source. They can be as simple as a sloppy handwriting, or as dangerous as writing ‘U’ for units instead of spelling out ‘units.’ That tiny error can turn a 5-unit insulin dose into 50 units, which could send someone into a life-threatening low-blood-sugar coma.

According to the Institute of Medicine, these kinds of errors cause at least 1.5 million injuries every year. The most common types include:

• Wrong dosage or quantity (19% of all errors)
• Illegible handwriting (22% of errors)
• Incorrect frequency instructions (like ‘QD’ instead of ‘once daily’)
• Drug name mix-ups (like Celebrex vs. Celexa)
• Missing or unclear purpose for the medication
• Use of dangerous abbreviations like ‘MS’ for morphine sulfate (which can be confused with magnesium sulfate)

Even electronic systems-meant to fix these problems-have introduced new risks. A 2019 study in JAMA Internal Medicine found that 34% of new error types came from e-prescribing systems. Why? Dropdown menus that put similar drugs next to each other. A doctor clicking too fast might pick ‘50 mg’ when they meant ‘5 mg.’

High-Risk Medications You Need to Double-Check

Not all medications carry the same risk. Some are called “high-alert” because even a small mistake can be deadly. These include:

• Insulin
• Warfarin (blood thinner)
• Hydrocodone and other opioids
• IV potassium chloride
• Heperin (anticoagulant)

These drugs make up only 8% of all prescriptions-but they’re behind 72% of fatal prescription errors. If you’re prescribed any of these, don’t assume it’s correct. Verify every detail.

For example, insulin is often written as ‘U’ for units. That’s dangerous. Always make sure it says ‘units’ spelled out. If you see ‘.5 mg’ without a zero in front, ask if it’s meant to be ‘0.5 mg.’ A missing zero can turn a safe dose into a dangerous one.

The Seven-Point Prescription Checklist

The FDA and patient safety experts agree: if you check these seven things every time you get a prescription, you’ll catch most errors before they reach your medicine cabinet.

1. Full drug name-No abbreviations. ‘Lamictal’ is a brand name. The generic is ‘lamotrigine.’ If it’s written as ‘Lamictal’ without the generic, ask why. Brand names can be confused with other drugs.
2. Precise dosage-It should use leading zeros (0.5 mg, not .5 mg) and avoid trailing zeros (5 mg, not 5.0 mg). Trailing zeros can make a 5 mg dose look like 50 mg.
3. Clear frequency-Avoid ‘QD,’ ‘BID,’ ‘TID,’ or ‘QID.’ These are outdated abbreviations. It should say ‘once daily,’ ‘twice daily,’ etc.
4. Total quantity-If you’re told you’ll take it for 10 days, does the prescription say 10 pills-or 100? A typo here can mean you run out early-or have too much.
5. Purpose of the medication-It should say why you’re taking it: ‘for high blood pressure,’ ‘for anxiety,’ etc. If it’s blank, ask. This helps catch wrong prescriptions.
6. Prescriber’s contact info-If the phone number or signature is missing, the pharmacy can’t call to verify. That’s a red flag.
7. Expiration date-Prescriptions expire. If it’s more than a year old, ask if it’s still valid.

A 2022 University of Michigan study found patients using this checklist caught 63% of errors before reaching the pharmacy. Without it, only 22% caught anything.

Red Flags to Watch For

Some mistakes are easy to spot if you know what to look for:

• ‘U’ for units-Always spelled out as ‘units.’
• ‘MS’ or ‘MSO4’-Could mean morphine sulfate or magnesium sulfate. These are completely different drugs. One calms pain. The other stops heart rhythms.
• ‘HC’ for hydrocortisone-Can be mistaken for heparin, a blood thinner. A mix-up here can cause bleeding.
• ‘ug’ for micrograms-Often confused with ‘units.’ Insulin errors from this mistake have killed people.
• Look-alike/sound-alike drugs-Zyprexa (antipsychotic) vs. Zyrtec (allergy pill). Celexa (antidepressant) vs. Celebrex (arthritis drug). These pairs are on the ISMP’s official error-prone list.

If you see any of these, pause. Ask your doctor or pharmacist to explain why that specific drug and dose were chosen.

Use the Teach-Back Method

Don’t just nod and walk out. After your doctor explains your prescription, repeat it back in your own words. This is called the teach-back method-and it works.

Say something like: ‘So, I take one 5 mg tablet of lisinopril once a day for my blood pressure, right?’

Johns Hopkins Medicine found this simple step reduces misunderstandings by 81%. It forces the provider to clarify if they made a mistake. And if they’re annoyed? That’s a red flag too. Good providers welcome questions.

Verify Electronic Prescriptions

Even if your doctor sends the prescription electronically, mistakes still happen. Pharmacies get the wrong drug because the system auto-filled ‘amoxicillin’ instead of ‘azithromycin.’

When you pick up your prescription, compare the label to your checklist. Does the name match? The dose? The frequency? If it doesn’t match what your doctor told you, don’t take it. Ask the pharmacist to call the doctor.

New tools can help. Apps like MedSafety let you take a photo of your prescription and scan it for errors. In a 2023 pilot study, users caught 68% more mistakes using the app.

Ask the Right Questions

The National Patient Safety Foundation’s ‘Ask Me 3’ program gives you three simple questions to ask every time you get a new medication:

1. What is my main problem?-This confirms the diagnosis matches the drug.
2. What do I need to do?-Clarifies the dose, timing, and duration.
3. Why is it important for me to do this?-Helps you understand the risk of skipping it or taking it wrong.

A 2021 study in JAMA Network Open showed patients who used these questions reduced medication errors by 44%.

What If You Spot an Error?

Don’t panic. Don’t argue. Just say: ‘I’m not sure this is right. Can you double-check?’

Pharmacists are trained to catch these mistakes. In fact, they now spend an average of 18.7 minutes per prescription verifying details-up from 6.2 minutes in 2015. That’s because 41% of that time is spent fixing errors from the prescriber.

If the doctor’s office won’t correct it, call them directly. Have your prescription in hand. Say: ‘I believe there’s an error in this prescription. Can you confirm the correct drug, dose, and instructions?’

Keep a copy of your prescription. If something goes wrong later, you’ll have proof of what was written.

Why This Matters More Than You Think

Prescription errors are the #1 cause of medical malpractice claims related to medications. The average payout? $287,500 per case. And that’s just the ones that are reported.

The cost to the healthcare system? Over $42 billion a year. That’s money spent on ER visits, hospital stays, and extra treatments-all because a doctor wrote ‘.5’ instead of ‘0.5.’

But here’s the best part: nearly all of these errors are preventable. The Agency for Healthcare Research and Quality says patient involvement cuts error risk by up to 50%.

You’re not just a patient. You’re a safety partner.

What’s Changing in 2025?

By 2025, all electronic health records will be required to give you real-time access to your prescriptions through secure apps. You’ll get alerts when a new one is sent-so you can review it before the pharmacy fills it.

Some hospitals are testing blockchain systems that track every change made to your prescription-from doctor to pharmacy. You’ll be able to see who changed what and why.

The FDA is also pushing for pictogram labels on all new drugs-simple pictures showing how to take the medicine. No more guessing if ‘three times a day’ means before or after meals.

The goal? By 2030, every prescription will require your digital confirmation before it’s dispensed. That’s not science fiction. It’s coming.

Final Thought: Your Safety Is Your Responsibility

Doctors are overworked. Pharmacies are busy. Systems are flawed. But you? You have nothing to lose by asking. And everything to gain.

Next time you get a prescription, pause. Check the seven points. Say it back. Ask why. Take a photo. Use an app. Don’t assume.

Because when it comes to your medicine, you’re not just a recipient. You’re the final checkpoint.