The justices did not comment in dismissing the state's appeal of last year's ruling by the Oklahoma Supreme Court. That ruling had invalidated a law requiring doctors to administer the drugs in accordance with U.S. Food and Drug Administration protocol.
Although the Supreme Court said in June that it would take up the case, the justices took the unusual step of first asking the Oklahoma court to clarify its ruling. Writing last week, the Oklahoma Supreme Court said that the law would not only limit drug-induced abortions, but also effectively ban them altogether.
Oklahoma is among five states — the others are Arizona, North Dakota, Ohio and Texas — that have sought to restrict medical abortions by limiting or banning off-label uses of drugs.
Among the drugs covered by the laws is mifepristone, originally known as RU-486. FDA approved its use in 2000 through the first seven weeks of pregnancy. It is prescribed along with a second drug, misoprostol.
Since the FDA approval, medical researchers and clinical trials have shown that mifepristone is effective in much smaller doses and for two weeks longer in a pregnancy, the law's challengers argued.
The Oklahoma Supreme Court noted that such off-label uses of drugs are standard medical practice.
More than 1.4 million women have taken the drugs to induce abortions. The state argued that at least eight women have died, justifying its law requiring adherence to the FDA protocol.