Forest Laboratories is the latest drugmaker to plead guilty to accusations of illegal marketing of its products in the USA.

The company has finalised an agreement-in-principle to resolve all aspects of the investigations led by the Department of Justice and the Attorney's Office for Massachusetts that began in January 2004. The probe related to Forest's marketing of the antidepressants Celexa (citalopram) and Lexapro (escitalopram) and an unapproved formulation of the thyroid treatment Levothroid (levothyroxine).

Forest is paying out $313 million plus interest and is pleading guilty to a single felony charge relating to misstatements by certain employees to US Food and Drug Administration inspectors during a November 2003 plant inspection. It also agreed to plead guilty to two violations of the Food, Drug and Cosmetic Act involving off-label promotion.

The company has also entered into a corporate integrity agreement with the Office of Inspector General of the US Department of Health and Human Services. It requires Forest to maintain its current compliance programme and to undertake "a set of defined corporate integrity obligations for a period of five years".