A 68-year-old man with metastatic prostate cancer starts morphine for bone pain. One week later his pain is controlled, but he has hard stools and

Question

A 68-year-old man with metastatic prostate cancer starts morphine for bone pain. One week later his pain is controlled, but he has hard stools and straining. He has no vomiting, fever, or abdominal distention. Which of the following is the most likely explanation for this patient's findings?

Accepted Answer

Reduced gastrointestinal motility mediated by mu-opioid receptors

Answer

Direct bacterial overgrowth from morphine

Answer

Pancreatic enzyme inhibition

Answer

Immune-mediated colitis

Answer

Pelvic floor denervation from prostate cancer

Opioid-induced constipation — USMLE Step 3 MCQ

A 68-year-old man with metastatic prostate cancer starts morphine for bone pain. One week later his pain is controlled, but he has hard stools and straining. He has no vomiting, fever, or abdominal distention. Which of the following is the most likely explanation for this patient's findings?