New FDA drug safety alert on azithromycin

The US Food and Drug Administration is warning that the antibiotic azithromycin should not be given long-term to prevent a certain inflammatory lung condition in patients with cancers of the blood or lymph nodes who undergo a donor stem cell transplant.

Azithromycin has been off-patent for many years, but two branded products were noted by the FDA: Pfizer’s (NYSE: PFE) Zithromax, about which the agency warned in 2013 can cause a potentially fatal irregular heart rhythm in some patients, and Pfizer's Zmax (azithromycin extended release) for oral suspension.

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