A sleep medicine expert testified on Thursday that Michael Jackson's reliance on the painkiller Demerol could have led to insomnia, but said the singer's doctor still erred by giving him propofol to sleep.
Dr Conrad Murray is on trial for involuntary manslaughter in the Thriller singer's 2009 death from an overdose of sedatives and the anesthetic propofol.
Prosecutors say Murray was negligent in his care, but defense attorneys hope to shift some blame onto another doctor who gave Jackson Demerol, which they say ultimately caused the insomnia Murray was treating.
Murray told police he gave Jackson propofol as a sleep aid on the day he died at the singer's Los Angeles mansion. His attorneys say Jackson gave himself an extra, fatal dose of the drug he called his milk due to insomnia.
Under cross-examination by defense attorney J. Michael Flanagan, sleep medicine expert Dr Nader Kamangar testified that his review of Jackson's records showed the singer received Demerol from Beverly Hills dermatologist Dr Arnold Klein.
I usually avoid using Demerol on patients, Kamangar said on the witness stand. It can actually activate someone, make them more hyper or excited, create more stimulation.
Flanagan asked, Can that cause insomnia?
It certainly can, Kamangar said.
In opening arguments three weeks ago, lead defense attorney Ed Chernoff told jurors that in the months before his death, Jackson visited Klein's office as much as two to three times a week.
Dr Arnold Klein addicted Michael Jackson to Demerol, Chernoff said at the time.
Los Angeles Superior Court Judge Michael Pastor has denied a defense request to call Klein as a witness, ruling that his testimony would be insufficiently relevant.
Klein could not be reached for immediate comment on Thursday.
On the witness stand, Kamangar said he did not have enough information to determine if Jackson had a Demerol dependency.
Flanagan pressed Kamangar about a 2010 Chinese study of the use of propofol to induce sleep for patients with severe insomnia that showed the drug helped those people.
Kamangar said the study was extremely experimental and did not justify using propofol for sleep in a hospital setting, let alone a home.
Even the authors in the end explain that this is just a very preliminary experiment and it needs way more studies to even imagine using this drug for (insomnia), Kamangar said.