The powerful sedative Propofol — also known as Diprivan — was among several narcotics found in Michael Jackson's rented suburban Los Angeles mansion, a law enforcement source tells FOXNews.com.

Given intravenously, Propofol is used as part of inducing general anesthesia in the operating room, and for heavy sedation of patients who are intubated in the intensive care unit.

Cherilyn Lee, a nurse who worked for Jackson, claims the pop star begged her for the drug, and that just four days before his death, a member of Jackson's staff called and said "'Michael needs to see you right away." She says she heard Michael in the background saying, "One side of my body is hot, it’s hot, and one side of my body is cold. It’s very cold."

Lee's description of Jackson's condition mirrors a 2007 FDA alert to healthcare professionals detailing "several clusters of patients who have experienced chills, fever, and body aches shortly after receiving propofol for sedation or general anesthesia."

RELATED: Click for the FDA Alert on Propofol.

Lee insisted she did not provide Jackson with the drug. "He wasn't looking to get high or feel good and sedated from drugs," she said. "This was a person who was not on drugs. This was a person who was seeking help, desperately, to get some sleep, to get some rest."

Authorities are investigating allegations that the 50-year-old Jackson had been consuming painkillers, sedatives and antidepressants. The federal Drug Enforcement Administration and California Attorney General Jerry Brown both are helping Los Angeles police investigate the possible involvement of prescription drugs in Jackson's death.

Some of the prescriptions also were dispensed under various patient names and doctors, leading investigators to believe aliases were used to obtain the drugs.

PHOTOS: Stars who died from prescription drug overdoses.

FOXNews.com spoke to Dr. Howard Nearman, department chairman of anesthesia at University Hospitals Case Medical Center in Ohio, about Propofol.

"Using this drug for insomnia is sort of like using a shotgun to kill an ant," Nearman said. "How someone could get a hold of this medication — and use it for the purpose that he allegedly used it for — is just incredible.”

RELATED: Click to read more of FOXNews.com Health's interview with Dr. Nearman.

If Jackson had this drug in his home, it would be against FDA guidelines. And if it was used in conjunction with any other painkiller or sedative, the combination could have ultimately led to his cardiac arrest and death.

“It should not be used out of an ICU or an operating room setting,” Nearman said. “Here at University Hospitals Case Medical Center… Diprivan can only be used by anesthesiologists or intensivists… and these people, who by virtues of training and experience, can handle this drug and manage any adverse side effect should they arise.”

It doesn't take a large dose of Diprivan to cause respiratory depression, which basically means a person will stop breathing, Nearman said, calling it a "slippery slope."

FULL COVERAGE: Click for FOXNews.com's full coverage of Michael Jackson's death.

“Once the breathing is slowed down or the blood pressure drops, eventually the heart won’t be able to sustain itself.”

Two autopsies — one of them a private exam requested by his family — have been performed in Jackson. An official cause of death is not expected to be announced for several weeks.

The Associated Press contributed to this report.