According to documents from the Santa Barbara County Sheriff's Department containing confidential interviews with two of Jackson's former security guards and obtained by CNN, Jackson asked employees to get prescriptions for him using their names, and even traveled to doctors in other states to acquire prescriptions.
The interviews (which were obtained in preparation for the singer's 2005 trial) suggested that the singer took more than 10 Xanax pills a night.
Xanax, which is prescribed for severe anxiety disorders and panic attacks, comes in sizes from .25 mg to 2 mg, with a maximum daily dosage of 6 mg.
An attorney for Michael Jackson's dermatologist told the Los Angeles Times that the doctor was subpoenaed for his medical records, which he turned over to the county coroner's office.
Dr. Arnold Klein said Wednesday that he on occasion gave the pop star the painkiller Demerol but .
Diprivan was allegedly found in Jackson's home following his death two weeks ago at the age of 50.
Complete coverage of Jackson's life and death
Appearing on CNN's "Larry King Live," Dr. Klein said that Demerol was among the strongest drugs he prescribed Jackson, and that doesn't know how he got Diprivan, usually administered by anesthesiologists in hospitals.
Dr. Klein said, "If you took all the pills I had given him in the last year at once, it wouldn't do anything to you."
Klein said Wednesday he discovered that Jackson was using Diprivan while on tour in Germany.
He said he warned Jackson the drug was dangerous: "I told him he was absolutely insane."