A nurse is caring for a cancer patient receiving subcutaneous morphine sulfate for pain. Which of the following nursing actions is most important in the care of this patient?
A. Monitor urine output
B. Monitor respiratory rate
C. Monitor heart rate
D. Monitor temperature
Correct Answer: B. Monitor respiratory rate
Morphine sulfate can suppress respiration and respiratory reflexes, such as cough. Patients should be monitored regularly for these effects to avoid respiratory compromise. Respiratory depression is among the more serious adverse reactions with opiate use that is especially important to monitor in the postoperative patient population.
Option A: Among the more common unwanted effects of morphine use is constipation. This effect occurs via stimulation of mu-opioid receptors on the myenteric plexus, which in turn inhibits gastric emptying and reduces peristalsis. Other common side effects include central nervous system depression, nausea, vomiting, and urinary retention.
Option C: Morphine can also affect the cardiovascular system and reportedly can cause flushing, bradycardia, hypotension, and syncope. It is also important to note that patients can experience pruritus, urticaria, edema, and other skin rashes.
Option D: Morphine sulfate does not significantly affect body temperature. Other reported side effects include lightheadedness, sedation, and dizziness. Patients often report nausea and vomiting, which is why in many emergency departments, morphine administration is with an antiemetic such as ondansetron.