Drowsiness or sleepiness is a common, temporary side effect of an increased dosage of morphine or other opioids. It usually takes two or three days to go away, but it can take longer. Occasionally it’s necessary to try other opioid medications to find the one that has fewest side effects for that person.

The overall fatigue that people feel with serious illness is generally due to a combination of factors: the illness itself, medications, any feelings of discouragement or depression, and possible complications such as a low blood count, decreased oxygen levels or an infection.

If fatigue persists and affects quality of life, it’s reasonable to investigate it, even when someone is in advanced stages of illness. It may help to change medications, treat complications, or use medications to improve energy.