The role of the powerful anesthetic propofol, commonly known by the trade name Diprivan in the demise of pop icon Michael Jackson appears more likely now that ABC News has learned from investigators that they will list the drug as a "contributing factor" to his death.
Sources have told ABC News that propofol was not the only drug found in Jackson's system during an autopsy following his death on June 25 – a finding that suggests the star could have been the latest famous figure to succumb to a deadly cocktail of medications.
However, doctors say propofol is certainly dangerous enough on its own to bring about death if improperly used. In a July 24 interview, Dr. Deepak Chopra, a celebrity physician and close friend of Jackson, said that the pop star may have even once hinted to him that he had abused the drug.
"On one occasion ... he said to me, 'Deepak, did you know there's something that takes you right to the edge, to the valley of death and it brings you back. Do you know anything about it?' And at that time I had never even thought of Diprivan or this anesthetic," Chopra told Chris Connelly in an ABC News Nightline interview.
"Well that's now in hindsight, that's Diprivan, isn't it? It takes you right to the edge if it's taken in sufficient amounts, and it takes you back. It's a short-acting anesthetic."
What Is Propofol?
Propofol is a sedative that is usually administered to patients who are undergoing surgery or another medical procedure. It is a fast-acting drug, with most patients receiving it losing consciousness within a matter of seconds.
The potency of propofol as an anesthetic is so widely known, in fact, that in anesthesiology circles, the drug, a white liquid, is nicknamed "milk of amnesia."
For more on the investigation into Michael Jackson's death, watch "Prescription for Death," on "Primetime: Crime," Tonight at 10 p.m. ET
While propofol is most often used to sedate patients before a medical procedure, it is also one that palliative care workers have been known to administer to terminal patients who are in pain or who have weeks or days to live.
What Are the Dangers of Propofol?
Propofol is widely known as a risky drug, and it is generally administered only in a controlled medical setting due to the dangers it poses.
"Propofol is an agent that requires very close monitoring and is often limited only to use by anesthesiologists," said Dr. Richard Page, head of cardiology at the University of Washington medical center. "The main issue with this agent is respiratory depression, which in turn could cause cardiac arrest."
"It is a very dangerous drug," said Dr. Brian Olshansky, a cardiologist at the University of Iowa who said he often uses the drug to place patients in deep sedation for certain heart procedures. "It is not for sleep. I cannot imagine anyone would use this outside a very regulated environment such as the availability of emergency respiratory equipment."
One main reason for this, he said, is the speed with which the drug has its effect.
"It rapidly induces unconsciousness and apnea," Olshansky said. "People stop breathing within seconds of being given the drug."
Why Would Anyone Abuse Propofol?
The rapid effect of the drug makes it an exceedingly unusual choice for abuse, said Dr. Jeff Guy of Vanderbilt University, who said such a situation would represent "a quantum leap in the issue of substance abuse."
But despite the effects and risk profile of the drug, some patients who've had the drug describe it as inducing "a very pleasant sleep" that "has the potential to be habit-forming," said Dr. Howard Nearman, chairman of the anesthesiology department at University Hospitals Case Medical Center in Cleveland.
And Dr. Bruce Goldberger, chief of forensic pathology at the University of Florida, noted that the drug "also acts as an aphrodisiac in men -- it has been reported that men have very vivid sexual dreams while under propofol anesthesia."