Rx Update: June 2003
Mary Ross, R.Ph., M.B.A., Joan Murhammer, R.Ph., Kevin Bebout,
R. Ph.
Peer Review Status: Internally Reviewed
There have been several reports in the literature of medication errors caused by the similarities of drug names. This look-alike/sound-alike name confusion may involve brand names, generic names, or a combination of brand and generic names. Such confusion may be compounded by illegible handwriting, incomplete knowledge of drug names, similar product packaging or labeling, or incorrect selection of a similarly named medication from a computerized product list. As new products are marketed, additional mix-ups can occur. The following examples highlight this problem.
Name confusion has been reported between ezetimibe (ZETIA®), a new medication to treat hyperlipidemia, and both lisinopril (ZESTRIL®), an angiotensin-converting enzyme inhibitor, and bisoprolol (ZEBETA®), a beta-blocker.
Confusion has been reported between the antidepressant nefazodone (SERZONE®) and the antipsychotic quetiapine (SEROQUEL®). Both drugs are available as 100 mg and 200 mg tablets.
There is a report of a handwritten order for the bronchodilator formoterol (FORADIL®) that was initially misinterpreted as ketorolac (TORADOL®), a nonsteroidal anti-inflammatory agent.
In another name confusion case, a hospitalized patient reported taking "Plaxil" at home, but she was actually taking clopidogrel (PLAVIX®), a platelet aggregation inhibitor. The admitting physician misinterpreted this verbal medication history as paroxetine (PAXIL®), an antidepressant and prescribed this medication for the patient, which caused several days of severe disorientation.
Letrozole (FEMARA®), a nonsteroidal aromatase inhibitor for the treatment of breast cancer, has been confused with the hormone replacement product ethinyl estradiol with norethindrone acetate (FEMHRT®). They both are prescribed to women for conditions relating to menopause.
Morphine sulfate extended-release capsules (AVINZA®) can be confused with the antibiotic ertapenem (INVANZ®).
Valganciclovir (VALCYTE®) and valacyclovir (VALTREX®) are both antiviral drugs with similar sounding generic and brand names that can be easily confused.
A number of problems have been reported with methylprednisolone acetate (DEPO-MEDROL®) and methylprednisolone sodium succinate (SOLU-MEDROL®). While both forms of methylprednisolone are used to treat inflammation, the acetate form is a slow-release depot that should never be administered intravenously (IV).
The likelihood of confusing similar sounding drugs is decreased when prescribers clearly print both the brand and generic names. Synonyms and abbreviations should always be avoided. Adding the indication for use may also help to clarify the order. All health providers should ensure that the agents prescribed for patients conform to therapy consistent with the patient's diagnosis. Incorrect routes of administration or doses that seem relatively large or small as compared to commercially available strengths should also warrant investigation prior to administration of the medication.