The pharmaceutical industry glimpsed its own ghost this week, and the apparition could not have arrived at a worse time for drug makers.

A report indicating that Merck used ghostwriters to produce medical journal articles in support of its subsequently discredited drug Vioxx has galvanized opponents to a federal proposal that would relax some restrictions on drug promotion.

The Food and Drug Administration has been considering a proposal to let drug makers use reprints of journal articles in promoting drugs for so-called off-label uses the F.D.A. itself has not approved. A main proviso of the proposal is that the articles must have been published in peer-reviewed medical journals.

The Vioxx report, published Wednesday by a leading medical journal, JAMA, has, however, raised new questions about the validity of many published research studies, even in peer-reviewed publications.

Opposition to the F.D.A. proposal has come from a diverse group that includes Public Citizen, New York State’s health commissioner and the Blue Cross Blue Shield Association, a trade association of 39 major health insurance plans.

The pharmaceutical industry is supporting the F.D.A. proposal. A working group of 10 major companies has enlisted the agency’s former chief legal counsel, Daniel E. Troy, to push the industry position.

In a news briefing in Washington on Thursday, the group presented its case that off-label uses of drugs and medical devices are necessary because scientists discover possible uses for new medical products before the F.D.A. has time to review them. Among other supporters of the F.D.A. proposal are the National Organization for Rare Disorders and the National Alliance of Mental Illness.

Dr. Kenneth Duckworth, medical director for the mental illness association, said that using drugs off-label is “one of the realities of treating people with illnesses that we don’t fully understand.”

Ghostwritten articles had been raised as a reason for concern about the proposal even before Wednesday’s article appeared in JAMA, the journal of the American Medical Association.

In a letter to the F.D.A. on March 21, the Blue Cross association’s vice president, Dr. Allan M. Korn, cited the possibility that ghostwritten articles could be used to bolster off-label uses of drugs.

The New York State health commissioner, Dr. Richard F. Daines, also wrote the F.D.A. on April 8 about his concerns of possible pharmaceutical industry manipulation of peer-reviewed journals and how those articles could be used to promote off-label uses.

His letter referred to the apparent misuse of journal articles in the off-label promotion of the epilepsy drug Neurontin. It was estimated that in 2002 more than 90 percent of Neurontin sales were for other off-label purposes, Dr. Daines’ letter said. Pfizer paid a $430 million fine in 2004 to resolve criminal and civil charges over off-label promotion of the drug.

After the JAMA article about Vioxx appeared this week, Dr. Daines said in a telephone interview that disclosures about Merck “points out the potential weakness” in the F.D.A. proposal.

“We just have so many concerns,” Dr. Daines said in a telephone interview Thursday. “You don’t know the publication’s true peer-review standards and transparency.”

Vioxx, a painkiller, was a best-selling drug before it was withdrawn from the market in 2004 following disclosure that it increased the risk of heart attacks. Last fall, Merck announced that it had agreed to pay $4.85 billion to resolve tens of thousands of Vioxx-related lawsuits.

Although off-label marketing was not an issue with Vioxx, the JAMA paper asserted that Merck had drafted dozens of research studies for Vioxx, then lined up prestigious doctors to put their names on the reports before publication.

The article, based on documents unearthed in lawsuits contending that Vioxx caused heart attacks, cited one draft of a Vioxx study that needed a big-name researcher, identifying the lead author as “External author?”

Merck has vigorously denied that the doctors named as authors on Vioxx papers did not play an integral role in producing the articles.

The lead author of the JAMA article, Dr. Joseph S. Ross of the Mount Sinai School of Medicine in Manhattan, said this week that his findings helped highlight flaws in the F.D.A. proposal’s reliance on peer-reviewed journals to provide the evidence supporting off-label drug use.

“What does it mean to be peer-reviewed,” Dr. Ross said, “if the company has essentially conceived the article, composed the draft and written the paper?”

Although the drug industry has generally not been permitted to promote drugs for off-label uses, physicians are allowed to prescribe federally approved products for any purposes as they see fit, and an estimated 20 percent of prescriptions are for off-label uses.

Dr. Sidney Wolfe, head of Public Citizen’s health research group, said his organization was concerned about the proposed F.D.A. rule change.

“It’s one thing if a doctor on her or his own chooses to prescribe it,” Dr. Wolfe said. “It’s another thing for the company to be promoting a drug for which there isn’t evidence that the benefits outweigh the risks.”

Drug makers have previously been allowed to distribute reprints of articles supporting off-label uses, but only with F.D.A. permission and only if they were also formally seeking approval of those uses.

Alan R. Bennett, a lawyer representing the industry coalition, said the old requirement was too burdensome. “That essentially required companies to promise to spend tens of millions of dollar to disseminate an article,” Mr. Bennett said.

After that law lapsed in 2006, the rules reverted to a prohibition on distribution of articles. But the industry said court rulings had made the legality of that prohibition unclear.

The new proposal requires that the articles published in peer-reviewed journals not be misleading. And they must also be circulated with a warning that the off-label use is not approved by the F.D.A. Mr. Bennett said the industry group believed that the peer-review process was adequate, particularly because the F.D.A. is currently overburdened and prosecutors have rigorously monitored inappropriate off-label promotion.

Representative Henry A. Waxman, a Democrat from California, complained last year that the F.D.A. proposal would also remove incentives for drug makers to sponsor clinical trials of drugs for new uses.