Cancer treatment is extremely difficult to treat because A) of the lack of availability of primary stem cells
B) cancer cells become mutated because they live a long time in the body
C) it is often a genetic disease
D) very often by the time it is diagnosed it has already metastasized

You are assessing an 86-year-old postoperative patient who has an unexpressive, stoic demeanor. when you enter the room, the patient is curled into the fetal position and your assessment reveals that his vital signs are elevated and he is diaphoretic. you ask the patient what his pain level is on a 0-to-10 scale that you explained to the patient prior to surgery. the patient indicates a pain level of “three or so.” you review your pain-management orders and find that all medications are ordered prn. how would you treat this patient's pain?