Pharmaceutical giant Pfizer Inc
will pay a record $2.3 billion to settle civil and criminal charges about how it marketed some of its drugs under a settlement to be unveiled on Wednesday, a source said.

The company, which is acquiring rival Wyeth , had warned in January that it had taken a $2.3 billion charge late last year to resolve investigations involving Bextra and other drugs, but did not provide details at the time.

The agreement will be unveiled later by the U.S. Department of Justice and Health and Human Services Department, the source said. Government spokespeople declined to comment. Pfizer officials could not immediately be reached for a comment.

It would be the largest settlement to date for improper marketing of prescription drugs, topping the $1.42 billion Eli Lilly and Co agreed to pay earlier this year for off-label sales of its Zyprexa schizophrenia drug.

Bextra, an arthritis drug, was withdrawn from the market in 2005 over safety concerns.

Pfizer had pleaded guilty in 2004 to an unrelated criminal charge of improper sales tactics related to its Neurontin seizure drug and its marketing practices have been under federal supervision since then.

In the earlier case, Pfizer's Warner Lambert subsidiary had been accused of marketing Neurontin for unapproved uses. Pfizer acquired Neurontin through its merger in 2000 with Warner Lambert.

(Reporting by Jeremy Pelofsky and Ransdell Pierson, editing by Bill Trott and Maureen Bavdek)