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High-alert medications, look-alike drug names and error-prone abbreviations for the PTCE

High-alert medications are drugs that cause significant harm when used in error, such as insulin, anticoagulants, opioids and concentrated potassium chloride. They sit in the PTCE's Patient Safety domain alongside look-alike and sound-alike names and error-prone abbreviations, all drawn from lists the Institute for Safe Medication Practices publishes.

Published September 19, 2026 · updated September 21, 2026

Patient Safety and Quality Assurance is 23.75% of the PTCE under the content outline that took effect on January 6, 2026. High-alert medications, error-prevention strategies such as tall man lettering, and types of medication errors are all part of it. The lists behind most of these questions come from the Institute for Safe Medication Practices, and the examples on this page are taken from those lists directly.

ISMP's website now sends visitors to ECRI, and its newest list files sit behind a download form. We read the most recent versions still openly posted on ismp.org and give each one's year. PTCB does not say which list entries appear on the exam, so treat the examples as the lists' contents and not as a prediction.

High-alert medications

ISMP defines high-alert medications as drugs that bear a heightened risk of causing significant patient harm when they are used in error. The point is not that these drugs are wrong more often. When an error does happen with one of them, the harm tends to be serious, so pharmacies add safeguards such as independent double checks and separated storage.

Methotrexate is worth singling out because it appears on both lists and because of how the error happens. Taken for rheumatoid arthritis or psoriasis, it is usually a once-weekly dose, so a daily dispensing error multiplies the weekly amount sevenfold. Our methotrexate fact sheet covers its boxed warning, side effects and counseling points in more detail.

Look-alike and sound-alike names

ISMP's list of confused drug names collects pairs that have been mixed up in reported errors because they look or sound alike. These pairs are all on ISMP's 2023 list, shown with the capital letters ISMP uses to tell them apart.

The capital letters are tall man lettering. ISMP's publication has two tables: one is FDA's approved list, with pairs such as buPROPion and busPIRone or glipiZIDE and glyBURIDE, and the other holds ISMP's additional recommendations, which it notes is not an official FDA list. FDA's own role comes from its name differentiation project, started in 2001 to evaluate reports of name confusion.

Error-prone abbreviations

ISMP's error-prone abbreviations list includes abbreviations that have been misread in harmful or potentially harmful errors. Several are also on The Joint Commission's Do Not Use list, which is why they come up as questions about what to write instead.

The zero rules are the ones most likely to show up as a calculation or transcription question, because a tenfold error from one misplaced decimal is easy to write and easy to miss. Sig codes on the PTCE covers the abbreviations that are still in everyday use.

Practicing the domain

Our free PTCB practice test draws Patient Safety questions at their outline weight, and the drug reference lists brand and generic names side by side, which is the fastest way to learn the look-alike pairs.

Common questions

Related

• Sig codes on the PTCE, and the ones you must never write
• The 2026 PTCE blueprint, domain by domain