Look-Alike / Sound-Alike (LASA) Drugs: The Pairs the PTCE Tests

What are LASA drugs, and why does the exam care?

Two drugs qualify as LASA when their names look or sound close enough that a busy tech can grab the wrong one — on a shelf, on a screen, or over the phone. That's not a trivia category: name confusion is one of the most common real-world dispensing errors, which is why the Patient Safety domain keeps returning to it. The exam typically shows you a pair and asks which drug matches a use, or which safety practice prevents the mix-up.

The classic LASA pairs to know

What is Tall Man lettering?

Tall Man lettering capitalizes the letters that differ between two confusable names — hydrOXYzine vs hydrALAzine — so the eye catches the difference on labels, shelves, and pharmacy software. It's promoted by ISMP and FDA as a standard error-prevention tool, and on the exam it's the go-to answer for “which practice reduces LASA errors?”

• arrow_rightOther tested LASA safeguards: separating look-alike stock on the shelf, barcode scanning at dispensing, and indication checks (“does this drug match the patient's condition?”).
• arrow_rightBrand↔generic knowledge is itself a LASA defense — knowing Celebrex is celecoxib (an NSAID) and Celexa is citalopram (an SSRI) makes the swap obvious.

How should I study LASA pairs?

• arrow_rightLearn each drug's job first. A pair only confuses you when both names are hollow. Once “hydralazine = blood pressure” is solid, the pair resolves itself.
• arrow_rightQuiz the pair in both directions — “which one is the antihistamine?” and “what does hydrOXYzine treat?”
• arrow_rightWrite the Tall Man version once by hand. Physically writing hydrOXYzine cements which letters differ.
• arrow_rightThen drill them as flashcards. get the app free — the Top 200 deck covers the LASA drugs with their classes, uses, and mnemonics.

LASA drugs — FAQ

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