The label for the antibiotic daptomycin (Cubicin) has been updated to warn of an association between the drug's use and a rare condition called eosinophilic pneumonia. Eosinophilic pneumonia results when the lungs fill with eosinophils, a type of white blood cell that performs two immune system functions, consuming foreign substances and promoting inflammation. Elevated eosinophil levels are typically related to parasite infections, allergies, and asthma. Symptoms of eosinophilic pneumonia include fever; shortness of breath; dyspnea that may require significant increases in oxygen concentrations or mechanical ventilation; and new infiltrates as seen on X-ray. Eosinophilic pneumonia can be fatal, and nurses should be on alert for this potentially serious adverse effect.

Daptomycin was originally approved in 2003 for the treatment of serious skin infections; in 2007 it was approved for the treatment of bloodstream infections (bacteremia) associated with intravascular lines or certain conditions, such as right-sided endocarditis. Daptomycin is effective against serious organisms such as methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus, vancomycin-susceptible enterococcus, vancomycin-resistant enterococcus, and ampicillin-resistant enterococcus. According to the drug's official prescribing information (http://bit.ly/9xltKj), "Daptomycin binds to bacterial membranes and causes a rapid depolarization of membrane potential [that leads to] inhibition of protein, DNA, and RNA synthesis, which results in bacterial cell death."

The label for daptomycin had already contained a notation of postmarketing reports of eosinophilic pneumonia. The revised label displays that information more prominently.

This label revision is the result of a review by the Food and Drug Administration (FDA) of six case reports, as well as one report in the literature, that the agency believes show an association between daptomycin use and eosinophilic pneumonia. In the seven reported cases, daptomycin had been prescribed for nonapproved indications, including osteomyelitis (in four of the cases), prosthetic hip infection, enterococcal endocarditis, and aortic valve endocarditis. Additionally, there have been 36 other case reports of eosinophilic pneumonia that might be related to use of the drug, but the association is less clear. (For more detailed information, read the full FDA Drug Safety Communication at http://bit.ly/dkyYp5.)

Nurses prescribing daptomycin or who care for patients receiving the drug should be on alert for changes that may indicate eosinophilic pneumonia. If they're not the prescriber, nurses should notify the appropriate provider and request a chest X-ray. Daptomycin should be discontinued if eosinophilic pneumonia is suspected. It's important to remember that eosinophilic pneumonia can lead to progressive respiratory failure and can be fatal if it's not quickly recognized and treated.