טיפול בכאב

Does Jewish law permit "heavy sedation" for the treatment of intractable pain? That is, when standard opioids and narcotics are unable to effectively treat a person's pain, would Jewish law permit a physician to intentionally sedate a person for an extended period of time in order to treat the pain as long as the physician believes that the sedation is not likely to shorten the person's life?

Again, I am not asking about "terminal sedation" or active euthenasia; I am asking about "heavy sedation" used to treat pain when there is no reason to believe that edating the person will shorten his or her life.

thank you