A U.S. Postal Service worker pleaded guilty Thursday to threatening his supervisor, saying an unwise mixture of pain medicine and liquor may have prematurely ended three decades of government service.

Samuel Davis Kemp, a 59-year-old mail handler at the postal service's Rutherford Avenue distribution center, landed in Roanoke's federal court after a July 26 incident that began when he was asked to come in four hours early for his 9 p.m. to 5 a.m. shift.

Kemp told U.S. District Court Judge James Turk that he hadn't taken medicine for a back problem before going in to work, and after several hours, he was suffering increasing pain.

He asked to go home for his medicine, and his supervisor told him to take a meal break and return when he could, Kemp said.

Back at home, Kemp told Turk, he took hydrocodone and waited for it to kick in. While he waited, "I did something stupid, your honor. I took a couple drinks of liquor."

Kemp said he did not realize the medication would intensify the alcohol's effects. He returned to work about 11 p.m. and soon was called into his supervisor's office. A co-worker had reported he smelled of alcohol.

Told he was drunk, Kemp asked to go home, he said. The supervisor said he was going to call police. The argument escalated, but Kemp said he couldn't remember what happened next.

"I do not remember threatening anybody. I don't remember anything until the next morning," Kemp said.

Assistant U.S. Attorney Charlene Day said Kemp shouted at his manager and threatened to kill him and other co-workers, then threatened police officers when they arrived. The officers pepper-sprayed Kemp and took him to Carilion Roanoke Memorial Hospital, where he was found to have a blood-alcohol content of 0.289 percent, Day said.

Kemp's attorney, Randy Cargill of the federal public defender's office, told Turk that a state charge of resisting arrest had been dismissed. A state charge of public intoxication ended with a $50 fine for Kemp.

Kemp said that he, union representatives and postal service administrators are discussing whether he will be allowed to work through February, when he planned to retire. His plea agreement contains a provision that when his employment ends, he will be banned from postal service property except when conducting personal business such as mailing something.

The plea agreement also says that prosecutors will recommend the low end of the range suggested by sentencing guidelines.

Sentencing is scheduled for Jan. 7.