Michael Jackson was “dependent” on painkiller Demerol and “possibly” even addicted to it at the time of his death, expert witness Dr Robert Waldman has revealed in court.

At the involuntary manslaughter trial of Dr Conrad Murray, who stands accused of administering dangerous amounts of powerful anaesthetic propofol to the singer, Jackson’s use of Demerol is a key facet of the defence.

Murray has admitted giving almost daily doses of propofol to Jackson to help him sleep. However, Murray’s attorneys argue the doctor was unaware that Jackson also received regular shots of Demerol from a Beverly Hills-based dermatologist.
This, the defence claimed, will have hampered Murray’s efforts to get the troubled star to sleep, as withdrawal from Demerol can cause insomnia. This would explain the large amounts of propofol that Murray was administering.

The idea that Jackson was on a cocktail of medication and seeing various doctors is key to the defence strategy.

Medical records show that dermatologist Dr Arnold Klein gave Jackson 900 milligrams of Demerol over three days in May 2009, and that the doctor also administered Botox and Restylane to the star for wrinkles and excess perspiration.

Witness Dr Waldman described the Demerol shots as “stiff doses” that were unnecessary alongside the skin treatment injections.

However, on cross-examination Waldman admitted that he could not say for certain whether Jackson was addicted to Demerol, and acknowledged that he was not certified as an addiction specialist.

Dr Murray, who faces up to four years in jail if convicted, has pleaded not guilty to the charges.