More than a dozen members of the House signed a letter to the Obama administration asking for an extension of the deadline. Senators Pat Roberts of Kansas and Jim DeMint of South Carolina, both Republicans, introduced legislation that would have barred the F.D.A. from removing Primatene from the market because they said the ban was a burdensome regulation.

Such lobbying is not unusual for the F.D.A. What was unusual, several top agency officials said, was the effort by Mr. Sunstein to persuade the agency to give Primatene a reprieve. “Usually, we can ignore all the lobbying stuff. We get it all the time,” a top F.D.A. official said. “But when we get pressure from inside the administration, that’s when it gets really tough.”

Mr. Sunstein must approve new government rules. But in the case of Primatene, the law and rules were already in effect. The F.D.A. did not need his agreement and resisted his entreaties, officials said.

Mr. Sunstein would not comment for this article. An administration official said Mr. Sunstein’s brief use of Primatene many years ago had played no role in his views. Mr. Sunstein was simply asking for more information about the product’s market removal and was worried about the removal’s effects on the poor and the uninsured, the official said.

Disquiet among senior F.D.A. officials culminated in December when Ms. Sebelius overruled the agency’s decision to allow over-the-counter access to an emergency contraceptive called Plan B One-Step, a decision many public health experts saw as a politically motivated effort to avoid riling religious groups and others opposed to making birth control available to girls.

The emergency contraceptive gradually loses effectiveness the longer women wait before taking it after unprotected sex, so the case for easier access is compelling, the F.D.A. had concluded. The current requirement that those 16 and younger need a prescription means pharmacies cannot place the pills on public shelves, making access more difficult for all.

Susan Wood, a former head of the office of women’s health at the F.D.A., had resigned in 2005 to protest the Bush administration’s repeated refusal to make emergency contraceptives available without a prescription. In 2009, the White House invited Dr. Wood to attend a ceremony during which Mr. Obama signed a presidential memorandum pledging to restore scientific integrity to government decision-making and to listen to scientists “even when it’s inconvenient — especially when it’s inconvenient.”