Eli Lilly & Co. pleaded guilty of illegally marketing its drug Zyprexa years ago and reached a deal to pay $1.42 billion to settle civil lawsuits brought by the Justice Department.

The pharmaceutical firm said it will pay $800 million to settle civil lawsuits, which include $438 million to the federal government and $362 million to states.

Eli Lilly will also pay $615 million to resolve it pleaded guilty to one misdemeanor violation of the Food, Drug and Cosmetic Act. The company marketed Zyprexa for dementia treatment from 1999 to 2001.

But, Lilly is not allowed to market Zyprexa to treat other illnesses than schizophrenia and bipolar disorder only, according to regulations by the Food and Drug Administration.

Zyprexa is the company's top-selling drug.