When one is in an induced coma it is because the doctor has provided drugs to sedate and anesthetize the individual in order to allow the body to rest and start to heal. This action is seen often after traumatic events when one has broken bones or has had major surgery. The individual always will have a breathing tube placed through their trachea into their lungs & on a ventilator to help them breathe.
Anesthetizing agents can be propofal (so?), Versed, fentanyl to name a few.
To reverse the induced coma, or to wake one up the drug of choice is called Narcan (naroxolone) (I may have spelled that wrong too). The Narcan is administered through an intravenous site (needle less catheter into a vein) and given a certain amount over time to wake them up. The procedure is closely monitored in a very controlled setting with nurses at the bedside.