just to make clear Propofol is decreases consciousness - while that can be considered a sleep - that is not a true sleep state that allows you to reach all sleep levels.. that in itself has significant damaging effects when used for the purposes of sleep. physically and mentally damaging.. this also causes issues with memory. (Someone planning a concert set, that is the opposite of effectiveness) It also causes low blood pressure (stories of him being super cold) .. Without creating speculation of what MJ dealt with it can also cause seizures, blurred vision, hallucination, mental break down, depression, anxiety, irregular heart beat, loss of breath, ... list continues!
PS. This 10 vs 50 dates thing brings in too much speculation to really get 100% truth.. We do know Michael originally agreed to 10 shows, and it's very plausible to say AEG convinced Michael to do 50 (telling him how crazy tickets sold, fans want to see him, beating Princes record - another world record).. Basically persuading him into agreeing. Now this does not speak for what Michael believed or did not believe he was capable of doing.. We cannot argue what Michael felt the time of signing the contract for 50 dates simply because all of the stories we hear about him saying "They are going to kill me.." etc, was regarding how he was being pushed during rehearsals etc. (Which at the time would not have started yet). I could guess while signing Michael was excited and felt great about himself knowing that he still created that type of frenzy, and knowing each show was set a couple days apart probably eased his mind (AT THE TIME)