Endocrinology

Numerous reports of medication errors have been reported because of drug products with similar sounding names.

FDA officials estimate that 10% to 15% of all reported medication errors result from drug name confusion.

With more than 9,000 generic names and 33,000 trademarked brand names, it may not be difficult to imagine the potential for drug name confusion and the potential for a related medication error.

The table lists only several of the numerous errors that have been reported to the U.S. Pharmacopeia medication error reporting programs.

The U.S. Pharmacopeia has determined that errors have been reported for more than 3,170 pairs of generic and brand drug names. The risk of drug name confusion increases when the sound-alike products are available in similar dosage strengths and forms.

FDA regulations

The FDA assists in regulating drug names. After phase-2 trials have been completed on chemical agents identified as potential new drug products, the FDA evaluates the manufacturer’s proposed proprietary name. The proposed name is assessed in several settings, including outpatient and inpatient settings, and as a verbal telephone order.

Although the FDA will not permit drug names that imply a specific medical claim, pharmaceutical manufacturers desire a product name that is uniquely identifiable. Some manufacturers consult with outside companies to develop unique and catchy drug names. For example, Advair (GlaxoSmithKline) relates to “advantage air for asthma.” Viagra (Pfizer) may imply “vitality” or “vigor.”

A drug’s generic and trade name, however, are regulated by the FDA, and the chosen names should minimize the risk for error.

Generic names are selected by the United States Adopted Names Council in association with the FDA. The generic names of some classes of drugs are similar and identifiable. The FDA reviews numerous submitted trade names each year, and approximately 30% are not approved.

Rarely, a specific trade name may be required to be changed after FDA approval and commercial availability because of confusion with similar drug names.

Drug name confusion

In 2005, the trade name of a drug labeled for use in Alzheimer’s disease, Reminyl (Ortho-McNeil Neurologics), was confused with a drug labeled for use in diabetes, Amaryl (Aventis). The former drug name was changed to Razadyne. However, Reminyl is available in Canada, and thus it may continue to be a cause of confusion if obtained from a Canadian source. The current generic name for the drug inamrinone (Inocor, Sanofi Aventis) had formally been known as amrinone. This generic name was changed because of confusion with another generic drug name, amiodarone (Cordarone, Wyeth).

Numerous specific drug names have been confused by health care practitioners and have been reported to medication error programs. Several of the drug pairs listed in the table have resulted in fatal outcomes.

More complete tables of similar sounding drugs are available from the Institute for Safe Medication Practices (www.ismp.org/Tools/confuseddrugnames.pdf) or the U.S. Pharmacopeia (www.usp.org). It may be useful to post these tables in office or inpatient settings.

What practitioners can do

Health care practitioners prescribing medications can reduce the risk of drug name confusion by several means. When prescribing drugs, practitioners should list additional information about the specific drug product. Inclusion of both the generic and trade name, the strength, dosage form and dosing instructions are helpful.

Listing the purpose and use of the drug in the directions can be additionally helpful. This can be useful in outpatient and inpatient settings. Handwriting that is difficult to read has been reported on numerous occasions to be a contributing factor in drug name confusion. Use of clearer handwriting or electronic prescribing can be helpful.

The use of “tall man” lettering may also reduce drug name confusion. For example, to avoid confusion with the drugs hydralazine and hydroxyzine, these names can be listed as “hydrALAZINE” and “hydrOXYzine.”

Other examples include “methylPREDNISolone” and “methylTESTOSTERone” or “ceFAZolin” and “cefTRIAXONE.” If an error due to drug name confusion occurs, all health care practitioners should report the error to the FDA’s MedWatch Adverse Reporting System at www.fda.gov/medwatch or 800-332-1088.

Edward Bell, PharmD, BCPS, is a Professor of Pharmacy Practice at Drake University College of Pharmacy and Blank Children’s Hospital in Des Moines, Iowa.

For more information:

• Progress with preventing name confusion errors. The Institute for Safe Medication Practices. Aug. 9, 2007. www.ismp.org/Newsletters/acutecare/articles/20070809.asp
• Hampton T. Similar drug names a risky prescription. JAMA. 2004;291:1948-1949.
• Rados C. Drug name confusion: preventing medication errors. FDA Consumer Magazine. 2005;39. www.fda.gov/fdac.