Look-Alike Sound-Alike (LASA) Medications Guide

High-Risk LASA Pairs

Look-alike sound-alike (LASA) medications are drugs with names that look or sound similar, leading to potential dispensing errors. The Institute for Safe Medication Practices (ISMP) publishes a list of commonly confused drug pairs that pharmacy technicians should memorize.

Dangerous LASA pairs include: metFORMIN vs. metroNIDAZOLE, hydrOXYzine vs. hydrALAZINE, predniSONE vs. prednisoLONE, clomiPHENE vs. clomiPRAMINE, and vinCRIStine vs. vinBLAStine (the latter pair has caused fatal errors).

Prevention in Practice

Pharmacies use multiple strategies to prevent LASA errors: Tall Man lettering on labels and shelf tags, physical separation of confused pairs on shelves, barcode verification during dispensing, and electronic alerts in pharmacy software.

When dispensing, always verify the medication by its NDC number rather than just the name on the stock bottle. Reading the full label, including the strength and manufacturer, provides additional verification points.

Study LASA Pairs

LASA medications are commonly tested on the PTCB exam. Memorize key pairs using flashcards and test yourself with mini exams.