Health officials began investigating Natrecor in May 2005 after the New York Times published an article describing how tens of thousands of patients were undergoing "tune-ups" by receiving weekly infusions over a period of several months at outpatient clinics. While legal, the FDA has not approved Natrecor for this off-label use. Cardiologists soon began speaking out against the drug's frequent use, pointing to the lack of clinical trials that support outpatient infusions and, more importantly, to Natrecor's link to kidney problems and death. Alternative medications, such as nitroglycerin, can be used just as effectively against heart failure, say the doctors.

Critics argue that Johnson & Johnson heavily promotes the medication, especially for off-label use, because of its lucrative sales. Figures for 2005 top $700 million, almost double last year's numbers. Unfortunately, say many opponents of the drug, it is within federal guidelines for a pharmaceutical company to send information to a physician about a drug's off-label uses, as long as it is deemed for educational purposes only.

Opponents of Natrecor's use in outpatient clinics received promising news in July 2005 when Scios sent a letter to physicians detailing how an expert panel found that more clinical trials need to be conducted to help answer the concerns raised by cardiologists across the country. The panel also recommended that Natrecor only be used in the hospital and not in an outpatient center. Scios announced that it would be instituting an educational program for physicians on the proper uses of Natrecor.