A major pharmaceutical manufacturer failed to persuade the Supreme Court to overturn a decision that it sold a cough-inhibitor called Benylin over the counter (OTC) illegally.

The justices let stand a decision in which the Food and Drug Administration prevailed over Parke-Davis & Co.

In September 1976, the FDA's Bureau of Drugs decided to continue Benylin Cough Syrup prescription only status, alleging that inadequate human testing and the drug's tendency to induce drowsiness required rejection of an adivsory panel recommendation that the product be sold over the counter.

The bureau action, later upheld by FDA Commissioner Alexander M. Schmidt, also has been challenged in an administrative hearing. That decision is pending.

In November 1976, Schmidt told parke-Davis to recall existing stocks of Benylin, which the Detriot firm had been selling without prescription since September 1975.

The company did not respond to Schmidt. He then ordered seizure of stocks in warehouses all over the country.

A few days, later, Parke-Davis went into U.S. District Court in Detroit to assert that Benylin was neither a "new drug" requiring FDA approval to be sold, nor a medicine limited to prescription sales.

Judge John Feikens ruled for the company. The 6th Circuit U.S. Court of APpeals reversed, holding that the FDA's enforcement action was not subject to the judge's review. The Supreme Court left the appeals court's decision standing.

A key issue in the case was a September 1974 tentative conclusion by an FDA panel of outside experts that Benylin (diphenhydramamine hydrochloride) was safe and effective for OTC sale.

In an exchange of correspondence a few months later, Gary Yingling, FDA'a associate chief counsel for enforcment, told Parke-Davis that "at this time" it was highly unlikely under enforcement priorities that the agency would subject the company to regulatory action were it to proceed with plans to sell Benylin OTC.

But he warned the company that it "assumes the risk" that the agency may not agree with the panel that Benylin was safe and effective for OTC market and may require different labeling that the panel recommended.