July 12, 2012 — The U.S. Food and Drug Administration (FDA) has sent Pfizer Inc. a warning letter over “false or misleading” statements in a brochure advertising the antibiotic Zithromax (also known as Zmax or azithromycin). According to the FDA, the advertisements make unsupported statements about the benefits of Zithromax without including important risk information. Furthermore, the brochure misrepresents the drug’s efficacy by overstating its benefits.
The FDA is specifically citing Pfizer for the following problems with the brochure:
- Minimizes important risk information
- Makes unsubstantiated superiority claims
- Omits material facts
- Broadens the indications for the drug
- Makes misleading efficacy claims
- Makes unsubstantiated claims for Zmax
The FDA has concluded that the brochures misbrand Zithromax and Zmax in violation of the Federal Food, Drug, and Cosmetic Act.
Zmax is approved for the treatment of mild to moderate bacterial infections that cause acute bacterial sinusitis due to Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae. It is also approved to treat community-acquired pneumonia.
The FDA was concerned because “the brochure omits the important risk of QT prolongation associated with Zmax use.” The QT interval is the heart’s recovery period between beats, and people with a prolonged QT interval are at risk of severe, life-threatening cardiac arrhythmias.
Furthermore, the brochure minimizes the risks of fatal allergic and skin reactions.
According to the FDA, promotional materials are misleading if they fail to prominently present risk information. Although the efficacy claims were large, bold, and colorful, the risk information was obscure, in block paragraphs, without headers. This presentation “undermines the communication of important risk information, minimizing the risks associated with Zmax, and misleadingly suggests that Zmax is safer than has been demonstrated.”
The FDA also warned that the brochure was misleading because it made unsubstantiated claims about the drug’s superiority. However, the FDA was not aware of any well-controlled studies comparing Zmax to other antibiotics that would support this conclusion. The brochure also implied that Zmax would be easier on a child’s stomach, when in fact the most common adverse reaction in children was vomiting, diarrhea, loose stools, and abdominal pain. The FDA called this claim “misleading” and “particularly concerning.”
The FDA requested that Pfizer immediately cease dissemination of all violative promotional material for Zmax that contain the problems outlined in the warning letter.
In May 2012, the New England Journal of Medicine published a study that linked Zithromax to a higher risk of sudden death when compared to amoxicillin, ciprofloxacin, or no drug. The study found that patients who had a history of cardiovascular disease had the highest risk. Currently, the FDA is conducting additional safety surveillance of the drug and is advising doctors to “be aware of the potential for QT interval prolongation and heart arrhythmias.”