WASHINGTON (AP) — The U.S. Justice Department on Thursday joined two lawsuits against Johnson & Johnson that accuse the company of illegally promoting its heart drug Natrecor for unapproved uses. J&J received approval in 2001 to market the drug to patients with severe congestive heart failure. But the two lawsuits cited by federal prosecutors allege the company soon began encouraging doctors to prescribe Natrecor for less severe forms of heart failure. “We have reviewed the allegations thoroughly and will address them in the courts,” said J&J spokesman Ernie Knewitz. Doctors are free to prescribe drugs for unapproved, or “off-label” uses, but companies are not allowed to promote those uses. In 2005, a panel of leading cardiologists called on J&J to stop promoting Natrecor for patients with less severe heart failure, including those who are no longer hospitalized. In 2007, J&J released results of a study that showed no medical benefit for those patients. Safety risks with the drug, which is administered directly into the vein, include low blood pressure, kidney problems and higher risk of death compared with older medications. The Justice Department said in a statement it would seek to recover federal money spent on the unapproved uses by Medicare, the government health plan for seniors. The two cases were filed in the Northern District of California by former sales managers for J&J unit Scios Inc., which is based in Fremont. Under federal law, whistleblowers who provide information about financial fraud against the government can receive up to 25 percent of the money recovered.