The Food and Drug Administration (FDA) issued a warning Friday concerning the long-term use of azithromycin (Zithromax, Zmax) for prophylaxis of bronchiolitis obliterans syndrome to patients who undergo donor stem cell transplants because of the increased potential for cancer relapse and death.


Results of a clinical trial found an increased rate of relapse in cancers affecting the blood and lymph nodes, including death, in these patients. FDA says they are reviewing additional data and will communicate their conclusions and recommendations when the review is complete.

The serious lung condition for which long-term azithromycin was being studied called bronchiolitis obliterans syndrome is caused by inflammation and scarring in the airways of the lungs, resulting in severe shortness of breath and dry cough. Cancer patients who undergo stem cell transplants from donors are at risk for bronchiolitis obliterans syndrome.

Azithromycin is not approved for preventing bronchiolitis obliterans syndrome. It is an FDA-approved antibiotic used to treat many types of infections affecting the lungs, sinuses, skin, and other parts of the body. The drug has been used for more than 26 years.

Patients who have had a stem cell transplant should not stop taking azithromycin without first consulting with your health care professional.

The manufacturer of brand name azithromycin is providing a Dear Healthcare Provider letter on this safety issue to health care professionals who care for patients undergoing donor stem cell transplants.

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