A major U.S. drug company, Forest Pharmaceuticals, has agreed to plead guilty to three charges related to selling an unapproved drug, promoting an antidepressant to children and obstructing federal agents.

Forest Pharmaceuticals promoted the use of the antidepressant Celexa to children when it was only approved for use by adults. Celexa and other similar drugs have been linked to suicide and suicidal thoughts in children. (CBC)

The company is facing fines and criminal penalties of over $300 million.

The charges date back more than 10 years when Forest was promoting its antidepressant, Celexa, for pediatric use when it was only approved for use in adults. Celexa is a selective serotonin reuptake inhibitor. In some children and teens it's been linked to suicide and suicidal thoughts.

Forest was also convicted of marketing its thyroid drug Levothroid without getting FDA approval. When the company was ordered to stop selling the drug in 2003, it increased production rather than scaling down. It also ignored a subsequent warning letter.

'These charges should serve as a warning to industry.'—Deborah Autor, U.S. Food and Drug Administration

A new formulation of Levothroid is now on the market with full approval. In Canada it's sold under the name Levothyroxine. The drug was approved by Health Canada in 2002.

The third count, a felony charge of obstruction, relates to false statements company employees made to federal inspectors during a 2003 FDA inspection at a Forest Pharmaceuticals plant.

"These charges should serve as a warning to industry," said Deborah Autor, director of the compliance office at the FDA's centre for drug evaluation and research.

"Any company that operates in violation of the FDCA [Food Drug and Cosmetics Act] and ignores FDA's warnings should be aware that a criminal action could follow."

Forest has also agreed to settle civil claims related to the disribution of Levothroid and the promotion of Celexa to children.

The drug company will pay $149 million to the U.S. government and state Medicaid agencies. In settling the claims Forest denies the allegations made in the suit.

"We are pleased to bring closure to this long-running investigation," said Howard Soloman, the chairman and CEO of Forest.

"We have continued to enhance our compliance program since the events at issue in this investigation, which occurred a number of years ago," he said.