The F.D.A. and federal lawyers, he said, need to restrict criminal prosecutions to especially egregious cases of off-label promotion.

In October 2011, Pfizer agreed to settle all civil claims in a whistleblower suit brought under the False Claims Act in connection with off-label promotion of the drug Detrol.

The case established for the first time that drug companies could be held liable under the False Claims Act for off-label promotion of pharmaceutical products.

More recently, AstraZeneca PLC has been fined $520 million in the United States for off-label promotion to doctors for their anti-psychotic drug, Seroquel.

Pam Lord, an InterMune spokeswoman, said any off-label promotion was done by executives no longer at the company.

Forest responded to these allegations that it "is committed to adhering to the highest ethical and legal standards, and off-label promotion and improper payments to medical providers have consistently been against Forest policy."

"We don't condone off-label promotion," he said.

Last year, for example, he secured a $430 million penalty in connection with the off-label promotion of Neurontin, a drug approved for epilepsy that Warner-Lambert had promoted for other uses.

Legal claims against the pharmaceutical industry have varied widely over the past two decades, including Medicare and Medicaid fraud, off-label promotion, and inadequate manufacturing practices.

Companies may also face closer federal scrutiny of their marketing practices, including so-called off-label promotion of drugs for conditions for which they have not been approved.