Pfizer (NYSE:PFE) has agreed to pay $55 million plus interest to settle allegations of misbranding by a subsidiary, according to a statement from the Department of Justice. The company's Wyeth unit is accused of promoting a drug for purposes other than those approved by the Food and Drug Administration.

Wyeth only had FDA approval to promote the drug, Protonix, for short-term treatment of one form of gastro-esophageal reflux disease. The government accused the company of promoting it as a treatment for all forms of the affliction, as well as for nighttime heartburn.

Wyeth allegedly conducted this promotion for nearly one and a half years, starting in early 2000.

Pfizer acquired Wyeth in 2009. In a statement quoted by the Associated Press, Pfizer said it is not a target or subject of the DoJ's case.