Soaring numbers of drugs with similar names have prompted the U.S. Pharmacopeia to ask providers to include an “indication for use” on prescriptions.

The recommendation is in U.S. Pharmacopeia's eighth annual MEDMARX report, which is based on a review of more than 26,000 records submitted to the MEDMARX database from 2003 to 2006.

The records implicate nearly 1,500 drugs in medication errors due to brand or generic names that could be confused. From these data, U.S. Pharmacopeia (USP) compiled a list of more than 3,000 drug pairs that look or sound alike, nearly double the number of pairs identified in USP's 2004 report, said Diane Cousins, R.Ph.

USP also operates, in conjunction with the Institute for Safe Medication Practices, the Medication Errors Reporting Program (MER), which allows health care professioals to report confidentially potential and actual medication errors directly to USP.

USP reviewed both MEDMARX and MER to summarize the variables associated with more than 26,000 look-alike and/or sound-alike (LASA) errors, of which 1.4% (384) resulted in harm or death. More than 670 health care facilities contributed 26,000 records, according to the report.

“We looked at lists of the top 200 drugs prescribed and used in hospitals, and virtually every time, all of the top 10 appeared within the USP similar names list,” said Ms. Cousins, USP's vice president of health care quality and information.

“Although pharmacy personnel, who are generally technicians, made the majority of errors, pharmacists as a group identified, prevented, and reported more than any other staff,” she said.

The report also identifies an emerging trend of look-alike drug names in computerized direct order entry systems. She added the LASA-related error problem is further compounded by the indiscriminate use of suffixes, as well as look-alike packaging and labeling.

Over the 3-year period, the drug most commonly confused with others was Cefazolin, a first-generation cephalosporin antibiotic. “We found it to be confused with 15 other drugs, primarily antimicrobials, which might be explained by the fact that this is the most frequently used class of medications,” said Ms. Cousins.

Drug mix-ups led to seven reported fatalities, including two due to confusion over the Alzheimer's drug Reminyl (galantamine) and the antidiabetes drug Amaryl (glimepiride).

In 2005, recognizing the high risk of confusion and subsequent fatal hypoglycemia, Ortho-McNeil Neurologics Inc. announced that the name Reminyl had been changed to Razadyne to avoid confusion with Amaryl. In another case, a physician was preparing to intubate a patient and calculated the dose for rocuronium (Zemuron), a preintubation agent used to assist with the procedure. The physician gave orders for the nurse to obtain the medication and indicated the volume to administer to the patient. The nurse obtained and administered the neuromuscular blocking agent vecuronium (Norcuron) instead, leading to a fatal heart arrhythmia.

Other deaths involved mix-ups between the anticonvulsant primidone and prednisone; the antiepileptic drug phenytoin sodium and the barbiturate phenobarbital; and Norcuron and the heart failure treatment Natrecor (nesiritide recombinant).

Errors occur with over-the-counter medications, too. Ms. Cousins described the aural confusion when an order for Ferro-Sequel 500 mg—an iron replacement—was transcribed as Serrosequel 500 mg and the order was misread as Seroquel 500 mg—an antipsychotic.

The rate of mix-ups involving brand name versus generic drugs was about evenly split, 57% and 43%, respectively, Ms. Cousins said, adding that while most errors were made in pharmacies, many are due to confusion over the prescribing physician's handwriting.

“Errors also are due to physicians using short codes for medications, such as 'clon,' for clonazepam or clonapine,” she said, adding that electronically written prescriptions using a computer or label machine would eliminate many errors.

It would also be helpful if the FDA were given more authority to force name changes during the drug review process.

The recommendation that physicians include indications for use in their prescriptions is not an attempt to impose on privacy, Ms. Cousins said. “All that is needed are simple inclusions, such as 'for sinus,' 'for heart,' or, 'for cough,'” she said. This also would help patients avoid confusion.

USP also recommends that “tall man lettering” be implemented in pharmacy software, labeling, and order writing to say, for example, “acetaZOLamide” (glaucoma) and “acetoHEXamide” (diabetes).

Where risk exists, USP recommends:

▸ Consider the potential for mix-ups before adding a drug to your formulary.

▸ Physically separate or differentiate products with similar names while they are being stored on the shelf.

▸ Disseminate information about products that have been confused at your facility, to build awareness among staff.

▸ Prohibit verbal orders for sound-alikes that have been mixed up at your facility.

“Physicians' offices should always require a read-back from pharmacists, making sure that they both say and spell the drug name,” Ms. Cousins said.

USP Asks Physicians' Help in Heading Off Medication Errors