The neurotransmitter has been a primary focus of drug abuse research because of its well-known effect on a part of the brain's reward system known as the nucleus accumbens. drugs that increase the activity of this neurotransmitter are most likely to result in physical dependence.

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?