FDA Talk Papers are prepared by the Press Office to guide FDA personnel in responding with consistency and accuracy to questions from the public on subjects of current interest. Talk Papers are subject to change as more information becomes available. The drug's manufacturer, Zeneca Pharmaceuticals, is now notifying health care providers of this possible drug side effect after FDA learned of six asthma patients who developed Churg-Strauss Syndrome while taking zafirlukast. These data, however, do not definitively demonstrate that the drug caused the condition.
Patients also experience inflammation of blood vessels, primarily in the lungs.
If left untreated, Churg-Strauss Syndrome can result in major organ damage and even death. Despite the severity of Churg-Strauss Syndrome, in light of the rarity of its occurrence FDA does not recommend that patients discontinue any asthma medication without consulting their health care provider. In fact, Churg-Strauss Syndrome is often treated with oral steroids, the same treatment that is used for patients with severe asthma. Based on present information, the agency continues to believe the benefits of this drug outweigh any of its known or potential risks. Thus far, all reported cases have occurred in patients whose steroidal asthma medications were being gradually lowered or discontinued while receiving zafirlukast.