WASHINGTON — Justice Samuel A. Alito Jr. issued an order on Friday temporarily ensuring that a common abortion pill would remain widely available while the Supreme Court considered whether to grant the Biden administration’s emergency request to preserve the Food and Drug Administration’s approval of the drug.

The order was meant to maintain the status quo while the justices studied the briefs and lower court rulings, and it did not forecast how the court would ultimately rule in the most important case about access to abortion since its conservative majority overturned Roe v. Wade last June.

Justice Alito set a brisk schedule for the court’s consideration of the case. His order, an administrative stay, instructed the groups challenging the F.D.A.’s approval of the abortion drug, mifepristone, to file their brief by Tuesday at noon.

The stay itself is set to expire on Wednesday at midnight, meaning the court is very likely to act before then and could in the coming days further curtail access to abortion, even in states where it is legal.

For now, though, Justice Alito, the member of the court responsible for overseeing the appeals court whose ruling is at issue, restored the state of affairs that existed before a ruling last week by a federal judge in Texas that would have suspended the agency’s approval of the pill and severely disrupted the availability of mifepristone.

The justice’s order was prompted by an emergency application filed Friday morning by the Biden administration asking the justices to intervene.

The administration’s brief asked the court to pause parts of an appeals court ruling that had limited the availability of the pill, part of the most commonly used method for ending pregnancies in the United States.

“If allowed to take effect, the lower courts’ orders would upend the regulatory regime for mifepristone, with sweeping consequences for the pharmaceutical industry, women who need access to the drug, and F.D.A.’s ability to implement its statutory authority,” the brief said.

In a second emergency application, filed by Danco Laboratories, which makes the branded version of mifepristone, the company’s lawyers said the justices should defer to the F.D.A.’s scientific expertise in determining that the drug was safe and effective.

On Wednesday night, a three-judge panel of the U.S. Court of Appeals for the Fifth Circuit, in New Orleans, issued a mixed decision, staying the most sweeping aspects of a decision from Judge Matthew J. Kacsmaryk that would have wholly overridden the Food and Drug Administration’s approval of the pill after more than two decades.

But the appeals court, in an unsigned order from a divided three-judge panel, temporarily let stand other aspects of Judge Kacsmaryk’s ruling, including by requiring in-person visits with doctors, rolling back the availability of the pills from the first 10 weeks of pregnancy to seven weeks and barring dispensing them by mail.

The panel’s ruling was provisional, and the court put the appeal itself on a relatively fast track, scheduling arguments for May 17.

The case was brought by several doctors and medical groups, including the Alliance for Hippocratic Medicine, which was incorporated in August in Amarillo, Texas, where the case was filed. Judge Kacsmaryk, a Trump appointee who is a longtime opponent of abortion, is the only federal judge in the Amarillo division in the U.S. District Court of the Northern District of Texas.

The appeals court majority wrote that the statute of limitations appeared to bar a challenge to the F.D.A.’s initial approval of the pill in 2000. But it said that later expansions of access to the pill were properly before the judge and that there were authentic safety concerns warranting suspension of regulations making it easier to obtain the pills.

The majority added that the plaintiffs appeared to have standing to sue because they might have to treat complications from the use of the pill.

In the Biden administration’s emergency application in the Supreme Court, Solicitor General Elizabeth B. Prelogar, representing the F.D.A., wrote that the plaintiffs lacked standing to challenge a drug they neither take nor prescribe and that they had provided no basis for second-guessing the agency’s scientific judgment.

Rather, she wrote, they relied on implausible speculation.

“F.D.A.’s approval of the drug does not require them to do or refrain from doing anything,” she wrote. “Yet the Fifth Circuit held that the associations have standing because some of their members might be asked to treat women who are prescribed mifepristone by other providers and who then suffer an exceedingly rare adverse event.”

In the emergency application by Danco Laboratories, the company’s lawyers said the appeals court’s ruling had created “regulatory chaos.”

“Leaving the Fifth Circuit’s ruling in place will irreparably harm Danco, which will be unable to both conduct its business nationwide and comply with its legal obligations,” the company’s brief said. “The lack of emergency relief from this court will also harm women, the health care system, the pharmaceutical industry, states’ sovereignty interests and the separation of powers.”

Judge Kacsmaryk once worked for First Liberty Institute, which says it is the largest legal organization in the nation focused exclusively on defending religious freedom. Democrats voted against confirming him to the bench in 2019 because of his history of opposing L.G.B.T.Q. rights.

In his ruling, Judge Kacsmaryk adopted the language of abortion opponents, referring to abortion providers as “abortionists,” to the challenged procedure as “chemical abortion” and to the fetus as an “unborn human” or “unborn child.” Legal scholars said the judge had relied on questionable scientific studies.

The government’s emergency application was harshly critical of the judge’s ruling.

“The district court countermanded a scientific judgment F.D.A. has maintained across five administrations; nullified the approval of a drug that has been safely used by millions of Americans over more than two decades; and upset reliance interests in a health care system that depends on the availability of mifepristone as an alternative to surgical abortion for women who choose to lawfully terminate their early pregnancies,” Ms. Prelogar wrote.

The application said the ruling was also novel. “To the government’s knowledge,” she wrote, “this is the first time any court has abrogated F.D.A.’s conditions on a drug’s approval based on a disagreement with the agency’s judgment about safety — much less done so after those conditions have been in effect for years.”

The case has returned the Supreme Court to an issue it not long ago said it was ceding to elected officials in Dobbs v. Jackson Women’s Health Organization, which eliminated a constitutional right to abortion after nearly 50 years. Writing for the majority, Justice Alito said that the political branches, rather than the courts, should set abortion policy.

The Dobbs decision concerned the Constitution, while Judge Kacsmaryk’s ruling mostly turned on principles of administrative law. But the new case demonstrated that legal disputes over abortion will continue to engage the justices.

The stakes are high. More than five million women have used mifepristone to terminate their pregnancies in the United States, and many studies have found it to be safe and effective. The drug is also approved for use in dozens of other countries.

In the United States, the protocol typically involves mifepristone in combination with a second drug, misoprostol, that are used in the first 10 weeks of pregnancy. About 60 percent of abortions in that time employ the two drugs rather than surgery.

The first drug blocks the effects of progesterone, a hormone without which the lining of the uterus begins to break down. The second one, taken 24 to 48 hours later, induces contractions of the uterus that expel its contents.

If access to mifepristone is limited, abortion providers may rely solely on misoprostol, which can be used on its own but is somewhat less effective and more prone to cause side effects.

The appeals court’s order is in conflict with ones issued by a federal judge in Washington State in another lawsuit related to mifepristone. That lawsuit, filed against the F.D.A. by Democratic attorneys general from 17 states and the District of Columbia, challenged extra restrictions that the agency imposes on mifepristone and asked the judge to prevent it from limiting access to the drug.

Judge Thomas O. Rice of the U.S. District Court for the Eastern District of Washington, an Obama appointee, did not lift the additional restrictions but ordered the F.D.A. to maintain the status quo. He blocked the agency from curbing the availability of mifepristone in the states that filed the lawsuit.

Lawyers for Danco wrote that the dueling orders put it “in an impossible position.”

The F.D.A., they wrote, “cannot permit Danco to simultaneously operate two separate distribution networks for two different parts of the country; that simply is not how the federal regulation of pharmaceuticals works.”