WEST PALM BEACH, Fla. – Rush Limbaugh could see a deal with prosecutors in a long-running prescription fraud case collapse after authorities found a bottle of Viagra in his bag at Palm Beach International Airport. The prescription was not in his name.

Mr. Limbaugh was detained for more than three hours Monday at the airport after returning from a vacation in the Dominican Republic. Customs officials found the Viagra in his luggage but his name was not on the prescription, said Paul Miller, a spokesman for the Palm Beach County Sheriff’s Office.

Mr. Miller said the alleged violation could be a second-degree misdemeanor. The sheriff’s office was investigating and will soon turn the case over to the state attorney’s office, which had no immediate comment yesterday.

Under the deal reached last month with prosecutors, Mr. Limbaugh was not to be arrested for any infraction for 18 months in exchange for authorities deferring a charge of “doctor shopping.” Prosecutors had alleged the conservative talk-show host illegally deceived multiple physicians to receive overlapping painkiller prescriptions.

Mr. Limbaugh also must submit to random drug tests and continue treatment for his admitted addiction to painkillers.

Mr. Limbaugh’s doctor had prescribed the Viagra, but it was “labeled as being issued to the physician rather than Mr. Limbaugh for privacy purposes,” Roy Black, Limbaugh’s attorney, said in a statement.

U.S. Customs and Border Protection examined the 55-year-old radio commentator’s luggage after his private plane landed at the airport, Mr. Miller said.

Investigators confiscated the drugs, which treat erectile dysfunction. Mr. Limbaugh was released without being charged.