How to Identify Look-Alike Names on Prescription Labels

Every year, thousands of patients in the U.S. receive the wrong medication-not because of a mistake in dosage, but because two drug names look or sound almost identical. Look-alike and sound-alike (LASA) drug names are one of the most common causes of preventable medication errors. A single mix-up between hydroCODONE and hydroHYDRAZINE can lead to overdose, organ damage, or even death. The good news? There are clear, proven ways to spot these dangerous similarities before they cause harm.

What Makes Drug Names Look or Sound Alike?

Not all similar drug names are dangerous. But when two names share 60-80% of the same letters or syllables, the risk spikes. For example:

• HydrOXYzine vs. HydrALazine
• DoXEpamine vs. DoBUTamine
• CISplatin vs. CARBOplatin
• Valtrex (valACYclovir) vs. Valcyte (valGANciclovir)

These aren’t typos. They’re real drug names approved by the FDA. The brain naturally fills in gaps-especially under time pressure. A nurse rushing between rooms might see “Hydroxyzine” on a screen and grab “Hydralazine” because the first five letters match. That’s why visual and auditory confusion is so dangerous.

Tall Man Lettering: The Standard Visual Fix

The most widely used tool to fight LASA errors is tall man lettering (TML). This isn’t just capitalizing random letters-it’s a precise system. The FDA and ISMP recommend capitalizing the parts of the name that differ, making the distinction instantly visible.

For example:

• HydrOXYzine
• HydrALazine

The capitalization draws the eye to the critical difference: “OXY” vs. “AL.” Studies show TML reduces visual confusion by 32%. But it only works if it’s applied consistently.

The FDA officially recommends TML for 35 high-risk drug pairs as of 2024, up from 23 in 2023. These include insulin brands like Humalog and Humulin, anticoagulants like Lovenox and Heparin, and sedatives like Ativan and Avinza. Every pharmacy label, EHR system, and automated dispensing cabinet should display these names in TML format.

Why TML Alone Isn’t Enough

Many hospitals think installing TML solves the problem. It doesn’t. A 2022 study in the Journal of Patient Safety found that TML alone cuts errors by only 32%. But when you add color coding, the jump is to 47%. Add the purpose of the medication-like “for anxiety” or “for blood pressure”-and effectiveness rises to 59%.

Here’s why: TML helps you see the difference. But if you’re tired, distracted, or under time pressure, your brain still skips over details. That’s why the best systems combine three layers:

1. Visual - Tall man lettering
2. Color - Highlighting high-risk pairs in yellow or red
3. Context - Adding the reason the drug is prescribed

At Johns Hopkins Hospital, combining all three cut LASA errors by 67% over two years. That’s not luck-it’s design.

How Electronic Systems Can Help (and Hurt)

Your EHR system is supposed to protect you-but it can also cause confusion. Many systems still list similar drug names right next to each other in dropdown menus. If you’re typing “Hyd” and see “Hydroxyzine” and “Hydralazine” side by side, your finger might pick the wrong one.

The Office of the National Coordinator for Health IT requires EHRs to prevent this. Confusing pairs must be separated by at least one other drug. That simple rule reduces selection errors by 41%.

Another rule: require at least five letters before showing drug options. This cuts down clutter and forces you to type more precisely. One hospital saw a 68% drop in error-prone dropdown lists after making this change.

But here’s the catch: alerts can backfire. Computer warnings for LASA pairs pop up constantly. Clinicians start ignoring them. A 2021 JAMA study found that 49% of LASA alerts are overridden-often because they’re too broad or appear for low-risk drugs. The fix? Only trigger alerts for the FDA’s official high-risk pairs. Done right, override rates drop from 73% to 31%.

What You Can Do: A 3-Step Verification Process

No matter how good the system is, humans still handle the drugs. That’s why the FDA and ISMP recommend a simple three-step check every time you handle a high-risk medication:

1. Read the full label before picking it up. Don’t just glance at the first few letters.
2. Confirm with another person before handing it off. A second set of eyes catches 80% of mistakes.
3. Read it again when giving it to the patient or placing it in the unit.

This process reduces errors by 52%. It takes less than 30 seconds. But in a busy clinic, it’s often skipped.

Handwritten Prescriptions Are Still a Big Problem

Even with all the tech, handwritten orders remain a major risk. A Reddit thread from 2023 with 87 pharmacy professionals found that 41% of LASA errors still came from poor handwriting. “I’ve seen ‘Hydroxyzine’ scribbled as ‘Hydralazine’ so badly that even the pharmacist couldn’t tell,” one user wrote.

And if the label is printed on a low-quality printer? The tall man letters might blur together. The Joint Commission requires a minimum 12-point font and 4.5:1 color contrast on labels. If the print looks faded or smudged, don’t use it. Ask for a new one.

Barcode Scanning: The Gold Standard

The most effective way to prevent LASA errors? Barcode scanning. When you scan the patient’s wristband and the medication at the same time, the system checks for matches. If the drug doesn’t match the order, it won’t let you proceed.

Barcode scanning reduces administration errors by 81%. But it’s expensive-about $153,000 per hospital to install. Still, hospitals that use it report 53% fewer LASA-related adverse events than those that don’t.

For smaller clinics, you don’t need the full system. Even a handheld scanner at the point of dispensing cuts errors by 86%. The key is using it at four critical points:

• Stocking meds in the pharmacy
• Dispensing to the nurse
• Refilling automated cabinets
• Before giving the drug to the patient

What’s Changing in 2025?

The FDA is expanding its list of TML-recommended drug names. By the end of 2024, all U.S. healthcare systems must use TML for the full 35 pairs. In 2025, the National Council for Prescription Drug Programs will roll out a new data standard that lets EHRs, pharmacies, and insurers share real-time LASA alerts.

Artificial intelligence is stepping in too. Google Health’s Med-PaLM 2 can predict LASA confusion with 89% accuracy. But it’s not replacing humans-it’s helping them. AI flags potential issues during prescribing, so doctors can choose a less confusing name before it’s ever written.

Final Checklist: Spotting LASA Names Before It’s Too Late

Use this quick guide every time you handle a prescription:

• Is the drug name on the FDA’s TML list? (Check ISMP or FDA websites)
• Are the different letters capitalized? (e.g., HydrOXYzine)
• Is the reason for use written on the label? (e.g., “for seizures”)
• Is the font at least 12-point and clearly printed?
• Did I read the full name aloud before giving it?
• Did I double-check with a colleague?
• Did I scan the barcode if available?

These aren’t extra steps. They’re safety nets. One extra second of checking can prevent a lifetime of regret.

What to Do Next

If you’re a clinician: Start using the 3-step verification process today. Even if your system doesn’t force it, make it a habit. One extra check can save a life.

If you’re a pharmacy manager: Audit your labels. Are all high-risk drugs using TML? Are barcode scanners working at every critical point? If not, prioritize fixing those gaps.

If you’re a patient: Always ask, “What is this medicine for?” If the label doesn’t say, ask again. Don’t assume the name is correct. You’re your own best safety net.

Medication safety isn’t about perfection. It’s about layers. TML, scanning, alerts, and human checks-each one catches what the others miss. When they all work together, errors drop. When even one fails, the risk rises. Don’t wait for a system to fix itself. Be the one who checks.