How to Identify Look-Alike Names on Prescription Labels

Every year, thousands of people in the U.S. get the wrong medication-not because of a mistake in dosage, but because two drug names look or sound almost identical. Look-alike drug names are one of the most dangerous but overlooked risks in healthcare. A pill labeled hydrOXYzine could easily be mistaken for hydrALAzine. vinBLAStine might be confused with vinCRIStine. These aren’t typos. They’re real, documented errors that lead to overdoses, allergic reactions, and even deaths.

Why Look-Alike Names Are So Dangerous

It’s not just about bad handwriting or rushed pharmacists. The problem is built into the names themselves. Over 3,000 drug name pairs in the U.S. have spelling or pronunciation so similar that even trained professionals mix them up. The Institute for Safe Medication Practices (ISMP) says about 25% of all medication errors involve look-alike or sound-alike (LASA) names. That’s one in four mistakes rooted in how drugs are named-not how they’re handled.

The FDA started its Name Differentiation Project in 2001 after seeing a spike in these errors. Since then, they’ve identified 35 high-risk pairs that need special labeling. The most common mistake? Confusing insulin names like Humalog and Humulin, or cancer drugs like doXEPamine and doBUTamine. One wrong dose can be fatal.

Tall Man Lettering: The Visual Fix

The main tool used to fight this problem is called tall man lettering. It’s simple: capitalize the parts of the drug name that are different. So instead of writing “hydroxyzine” and “hydralazine,” you write:

• hydrOXYzine
• hydrALazine

This tiny change makes the difference pop visually. Studies show it cuts confusion errors by about 32%. The FDA recommends capitalizing 2 to 4 letters that create the clearest visual split-always starting from the left side of the name. The goal isn’t to make the name harder to read; it’s to make the difference impossible to miss.

You’ll see tall man lettering on electronic health records, pharmacy labels, automated dispensing cabinets, and even in printed prescriptions. But here’s the catch: it only works if it’s used consistently.

Where Tall Man Lettering Fails

Many hospitals and clinics use tall man lettering in their EHR systems-but not on the actual prescription labels printed for patients. One nurse in Portland told me she saw a handwritten script for “hydrocodone” that had no capitalization. The pharmacy’s system showed it correctly as “hydrOCODONE,” but the paper label didn’t. She had to double-check the bottle to be sure. That’s the gap.

Handwritten prescriptions are still a huge problem. A 2023 survey found that 41% of LASA errors happened because a doctor wrote the name without tall man lettering. Poor printer quality makes it worse. If the ink smudges or the font is too small, even the best labeling becomes useless.

Another issue? Not all systems use the same rules. One pharmacy’s software might show “cisPLAtin” while another shows “cisPLAtin.” That inconsistency creates confusion, not clarity.

What Works Better Than Tall Man Lettering Alone

Tall man lettering helps-but it’s not enough. The best results come from combining it with other layers of protection.

• Color coding: Some hospitals use colored labels for high-risk drugs. Red for insulin, yellow for opioids. When paired with tall man lettering, error rates drop another 15%.
• Purpose-of-treatment notes: Adding “for anxiety” next to “hydroxyzine” or “for high blood pressure” next to “hydralazine” makes it harder to grab the wrong bottle. One study showed this cut errors by 59%.
• Barcode scanning: Scanning the drug and the patient’s wristband before giving it reduces errors by 89%. It’s the gold standard-but expensive. Hospitals spend an average of $153,000 to install the system.
• Computer alerts: EHR systems can pop up warnings when you select two similar names. But too many alerts make clinicians ignore them. A 2021 study found that 49% of LASA alerts were overridden because they were too frequent or vague.

The most successful programs, like the one at Johns Hopkins Hospital, use all four: tall man lettering, color, purpose notes, and scanning. They cut LASA errors by 67% in two years.

How to Protect Yourself as a Patient

You don’t have to rely on the system to get it right. Here’s what you can do:

1. Read the label twice. When you get your prescription, read the full name out loud. Compare it to what your doctor told you. If it says “hydroxyzine” and you were told you’re getting something for allergies, but the bottle says “hydrOXYzine,” that’s correct. If it says “hydrALazine,” that’s for blood pressure-ask why.
2. Ask for the purpose. Say: “What is this medicine for?” If the pharmacist says “it’s for high blood pressure” and you were told it’s for itching, something’s wrong.
3. Check the shape and color. If your pills look different than last time, ask. Generic versions can change appearance, but the name should still match.
4. Use the pharmacy’s app. Most pharmacies now let you view your prescriptions online. Compare the digital label to the physical one. If the tall man lettering is missing online, call them.

A 2022 study found that patients who asked these simple questions reduced their risk of a LASA error by 60%.

What’s Changing in 2025

The FDA added 12 new drug pairs to its tall man lettering list in late 2023. That brings the total to 35 high-risk names that must be labeled with capitalization by December 2024. New drugs entering the market now go through a computer analysis that predicts confusion risk using algorithms like BI-SIM (for spelling) and ALINE (for sound). Since 2018, this tool has blocked 17 drug names from ever being approved because they were too similar to existing ones.

EHR systems are also being required to stop showing similar drug names next to each other in dropdown menus. Before, you’d scroll and see “doxepin” and “dobutamine” right next to each other. Now, they’re separated by at least five other names. That alone cut selection errors by 41%.

By 2026, the ISMP wants all U.S. healthcare settings to use tall man lettering on every prescription-digital or paper. That includes clinics, nursing homes, and even veterinary offices.

What to Do If You Spot a Problem

If you notice a drug name on your label that looks too similar to another, or if tall man lettering is missing, speak up. Report it to your pharmacist. Ask them to double-check. If they dismiss you, call the pharmacy’s compliance line or file a report with the FDA’s MedWatch program. You’re not being difficult-you’re preventing a mistake.

One pharmacy tech in Ohio told me she caught a mix-up between “furosemide” and “fluconazole” because the label didn’t show tall man lettering. She flagged it. The patient was scheduled for heart surgery. Getting the wrong drug could have caused kidney failure. She saved a life by asking one question: “Why does this look like a fungal infection pill?”

Final Thought: It’s Not Just About Letters

Look-alike names aren’t a glitch. They’re a design flaw in how we name drugs. The system is trying to fix it-but only if everyone plays their part. Pharmacists, doctors, nurses, and patients all need to be alert. Tall man lettering helps. But your eyes, your questions, and your willingness to double-check are just as powerful.