The most effective way to prevent further confusion between Topamax and Toprol-XL—the brand names of topiramate and metoprolol succinate—would be to change one of their names, according to Michael R. Cohen, president of the Institute for Safe Medication Practices.
A complete name change would not be necessary, Mr. Cohen said in an interview; capital letters could be used to accentuate the differences between the two words.
“They have used capitals, but both companies used all capitals for the names,” which can actually detract from a visual recognition of the different letters in each name. “What they really need to do is identify with capitals the characters that are unique to each name—that would make the differences stand out more.”
However, a name change was not included among the suggested safety precautions in a “Dear Health Care Provider” letter sent out by Ortho-McNeil Pharmaceutical Inc., maker of Topamax.
Reports of mixups between Topamax and Toprol-XL (AstraZeneca) have been submitted to the Food and Drug Administration, the World Health Organization, and the U.S. Pharmacopeia, an Ortho-McNeil press release said. The reports document prescriptions that have been incorrectly written, labeled, and/or dispensed, resulting in some patients taking the incorrect drug.
Neither company would say how many medication errors have been reported, but the press release did say such errors can lead to “potentially serious health consequences associated with either unintended exposure to a medication or lack of a needed therapy.” Patients taking topiramate, an anticonvulsant, can experience a sudden increase in seizure activity, and those taking metoprolol succinate, a β-blocker, can experience increases in blood pressure, angina, or even myocardial infarction if therapy stops abruptly.
The errors have been traced not only to similarity in trade names, but also to the products' proximity on pharmacy shelves or computerized listings, and identical dose strengths in the tablet formulations.
Both drugs also recommend dosage titration, which could be another contributing factor, according to Ortho-McNeil's “Dear Health Care Provider” letter, which is part of the company's educational campaign targeted at physicians and pharmacists.
To help ensure that patients receive the correct medication, the campaign encourages physicians to:
▸ Be alert to the possibility of medication errors in patients prescribed Topamax or Toprol-XL.
▸ Be aware of the possibility of medication errors in patients presenting with unexpected signs or symptoms while on Topamax or Toprol-XL.
▸ Confirm the brand and generic names and dosage on written and oral prescriptions.
▸ Print legible prescriptions that include the brand and generic names, with indication.
▸ Counsel patients about the brand name, indication, and proper use of each drug.
Neither Ortho-McNeil nor AstraZeneca has announced plans to alter its drug's trade name in any way. In the absence of such changes, Mr. Cohen suggested that physicians take the initiative to explain the situation to patients and highlight the drug names in a way that makes the prescription very clear to the pharmacist.
Such an effort helps patients advocate for their own safety, he said. “Highlight the unique letter characters in each name, and take a few minutes to let their patients know that there have been some mistakes.”
Additionally, he said, pharmacists dispensing the medications can easily catch any errors with a few words to the person picking up the medication. “All they have to do when handing it out is to repeat the name of the drug to the patient and ask, in the case of Topamax, for example, 'Are you using this for seizures or migraines?'”