Louisiana has filed a lawsuit against drug maker Fresenius Medical Care North America and its nearly 100 Louisiana clinics over the use of two dialysis drugs — since recalled by the federal government — that could contribute to fatal heart attacks.

Fresenius knew as early as 2004 that its GranuFlo and NaturaLyte product, if not used properly, could elevate dialysis patients’ bicarbonate levels and increase the risk of a heart attack, according to the lawsuit filed in 19th Judicial District Court. The company, based in Waltham, Massachusetts, also knew that its dialysis machines required special instructions when using GranuFlo to reduce those risks, the state claims.

But Fresenius didn’t warn patients or the roughly 1,500 non-Fresenius dialysis clinics using the drugs of the dangers, the lawsuit says. Fresenius tried to conceal the dangers from the public and the U.S. Food and Drug Administration, it said.

It wasn’t until March 2012, when the FDA initiated a Class I recall — the most serious type of recall where use of a product will cause serious health problems or death — that Fresenius warned the medical community about the products, the lawsuit said.

A Fresenius study found that in 2010, 941 dialysis patients at 667 of its clinics suffered a cardiac arrest during treatment.

The lawsuit, filed by the state Attorney General’s Office, says Fresenius violated Louisiana law in an effort to defraud dialysis clinics, physicians, the state and its residents.

The state is entitled to civil penalties of $5,000 per violation under Louisiana’s Unfair Trade Practices and Consumer Protection Law.

Louisiana is also asking the court to force Fresenius to pay back any profit it made on the sale of GranuFlo.

Fresenius officials could not be reached for comment Friday afternoon.

A number of class-action lawsuits have been filed against Fresenius.