(July 1, 2009)

LOS ANGELES -- The powerful sedative Diprivan was already under question by federal regulators prior to Michael Jackson's sudden death.

Also known as Propofol, Diprivan was among a slew of pharmaceuticals reportedly found inside Jackson's rented Holmby Hills estate.

The drug is one of the most widely used general anesthetics in the United States. It is commonly used to put patients to sleep or place them in a semi-conscious state during uncomfortable procedures, like colonoscopies.

The drug can be so dangerous that the U.S. Food and Drug Administration says only those trained in general anesthesia should administer it, the Los Angeles Times reported.

Nearly all of the small but growing number of abuse cases involve doctors and other medical personnel. Because a dose lasts just a few minutes, it's not uncommon for users to inject themselves 80 times a day as they search for the brief high or the sensation of slipping into unconsciousness, The Times reported, citing physicians who have studied Diprivan abuse.

Three days before Jackson's June 25th death, the American Association of Nurse Anesthetists recommended the drug be placed in a secure environment.

A 2007 study by researchers at the University of Colorado revealed that most anesthesiology departments did not have a system to monitor Diprivan, as was done with narcotics like Demerol.

Doctors say going under with Diprivan, even for several hours, is not the same as sleeping and should never be used for insomnia treatment. Most people who abuse the drug started using it to overcome insomnia, according to Dr. Omar Manejwala, associate medical director at the William J. Farley Center at Williamsburg Place in Virginia.

Beverly Hills dermatologist Dr. Arnold Klein, who treated Jackson for 25 years, has said the pop star was using Diprivan with an anesthesiologist "to go to sleep at night" while touring Germany. The last time Jackson toured that country was 1997.

Investigators are looking into whether the drugs found in Jackson's home were properly prescribed and whether they contributed to his death.

Autopsy results are expected to be released in about 2 weeks.

It's reported that Jackson's body had multiple injection marks on his body when he died. He also allegedly used a slew of aliases, including Omar Arnold and Jack London, along with the name of a bodyguard and the office manager of one of his doctors, to obtain prescription medications.

Jackson, an insomniac, had allegedly begged a registered nurse for the powerful sedative in the days before his death.

Coroner's officials have served subpoenas on several of Jackson's physicians. Those told to submit "any and all" of Jackson's medical files and "radiology and psychiatric records" included Dr. Klein, whose attorney says has not been accused of any wrong-doing.

A senior law enforcement official told the Times that if Propofol is found to have caused Jackson's death prosecutors could bring charges against doctors or others involved in giving him the drug. Prosecutors have discussed a range of possible charges "all the way up to involuntary manslaughter," the official said.