Conrad Murray would not take the job as Michael Jackson's personal doctor if he could go back in time.

Conrad was sentenced to four years in jail, serving two, and stripped of his medical licence for his role in Michael's death, and although he cherishes his friendship with the musician, his work with the 'Bad' hitmaker has cost him too much pain in his life and he would spurn the job if he was offered it again.

Conrad - who has written a book about his life with Jackson entitled 'This Is It! The Secret lives of Dr. Conrad Murray and Michael Jackson' - exclusively told BANG Showbiz: "The book is very honest, and the book is very crude presentation of life and what we experienced together. There's no doubt that I have been damaged, definitely. Will I ever get over this? No, how could I forget this, I'll never forget this in my life. I will tell you, regretfully, if I could live my life again, I wouldn't do it, I wouldn't work with him. Michael Jackson is a good man, but no."

Conrad, 63, insists if he had known the true extent of Michael's drug use he would never have given him Propofol which he pleaded for to help him sleep as the stress of rehearsing for his planned 'This Is It' concert residency at The O2 in London became too much to cope with. Instead he would have got him into a drug rehab facility.

The medical expert was shocked when he discovered at how large a dose of Demerol Michael was regularly taking along with Midazolam.

He said: "I was very disappointed in Michael and hurt because he did not tell me the truth (about his drug use). Had he told me I would have wanted to rehab him. I would have helped him, in the same way I am interested in helping other human beings.

"I learnt more about Michael's drug abuse after he passed away ... I think that the Demerol thing may have started with the Pepsi commercial, the day he burnt his head and was injured. It is very easy to give someone a narcotic and the next thing they are hooked ... I have had patients who came in with broken bones after a motor vehicle accident and you use Demerol for the pain. We gave them anywhere from an average of 25 to 75 milligrams of Demerol based upon their weight and that patient's pain would be totally resolved and they would be relaxed, even with broken bones. Now, if you look at the records that were published in the trial, and it's also on my website, Doctor Murray Talks, you will see Michael was taking upwards of 975 milligrams of Demerol daily in addition to Midazolam."

Recalling how he questioned father-of-three Michael's requests for Propofol, Conrad added: "I disagreed with the Propofol from the start. I asked him, 'Why would you be using that?' Michael explained to me because of his high level of insomnia, which occurs when he is getting ready for a tour and wants to wind down and therefore it was used for sleep."

'This Is It! The Secret lives of Dr. Conrad Murray and Michael Jackson' is available to buy now.