This column was prepared by the Institute for Safe Medication Practices (ISMP), an ECRI affiliate.

Every pharmacy should strive to continually improve their medication-use system and provide the safest, highest quality of care possible. To accomplish this, practice sites must assess their risks associated with the medication-use process by monitoring actual and potential medication errors and adverse drug events. Below are two issues that warrant attention and priority if you have not already taken action to mitigate the risk.

Selecting the Wrong Medication After Entering Only the First Few Letters of the Drug Name

Entering just the first few letter characters of a drug name, or a combination of the first few letters and product strength, potentially allows the presentation of similar looking drug names on computer order entry screens. This increases the risk of selection errors. Examples of drug selection errors that resulted after entering the first few letters of the drug name include mix-ups between Ambien® (zolpidem) and ambrisentan; Briviact® (brivaracetam) and Brilinta® (ticagrelor); and tramadol and trazodone. Also, entering “met” has often led to confusion between methylphenidate, methadone, metolazone, methotrexate, metformin, and metronidazole; and entering “meth10” has led to confusion between methadone 10 mg and methylphenidate 10 mg.

Guard against these errors by entering a minimum of the first five letters of a drug name during product searches, which will reduce the number of similar names that appear together on the same screen. Work with your information technology staff and computer vendor to implement this recommendation. Until then, practitioner awareness of this problem may help change personal practice habits.

Daily Instead of Weekly Oral Methotrexate for Non-Oncologic Conditions

Prescribing, dispensing, or administering oral methotrexate daily instead of weekly for non-oncologic conditions continues. A December 2019 QuarterWatch analysis of inadvertent daily methotrexate administration over 18 months between 2018 and 2019 demonstrated that about half of the reported errors were made by older patients who were confused about the frequency of administration, and the other half were made by health care providers who inadvertently prescribed, labeled, or dispensed methotrexate daily when weekly was intended.1 An analysis sponsored by United States FDA suggests that up to four per 1,000 patients may mistakenly take the drug daily instead of weekly.2

Other causes of methotrexate wrong frequency errors more recently reported to ISMP include:

  • A mix-up between the look-alike, round, yellow tablets of methotrexate and folic acid, the latter of which is often prescribed with methotrexate to lessen its toxicity
  • A fatal mix-up between metolazone 2.5 mg, the intended drug, and methotrexate 2.5 mg, caused in part by entering just “met” into the order entry system and selecting the wrong drug from the search menu
  • A fatal mix-up between Paxil® (paroxetine) 10 mg, the intended drug, and Trexall® (methotrexate) 10 mg, caused by mishearing a prescription called in to a community pharmacy

To reduce the risk of error, consider the following strategies:

  • implement computer systems that default to a weekly dosage regimen when entering electronic orders or prescriptions for oral methotrexate;
  • require an appropriate oncologic indication for all daily methotrexate orders; and
  • provide patient and family education about the importance of weekly administration. To assist with education, provide patients and families with a copy of ISMP’s free consumer leaflet on oral methotrexate.


Moore TJ, Furberg CD, Mattison DR, Cohen MR. QuarterWatch 2019 quarter 2: Scope of injury from therapeutic drugs. Institute for Safe Medication Practices. 4 Dec 2019.

Herrinton LJ, Woodworth TS, Eworuke E, et al. Development of an algorithm to detect methotrexate wrong frequency error using computerized health care data. Pharmacoepidemiol Drug Saf. 2019 Oct;28(10):1361-1368.

Have you experienced a medication error or close call? Report such incidents in confidence to ISMP’s National Medication Errors Reporting Program online at or by email to to activate an alert system that reaches manufacturers, the medical community, and Food and Drug Administration (FDA). To read more about the risk reduction strategies that you can put into practice today, subscribe to the ISMP Medication Safety Alert! newsletters at