What is the most common side effect of the opioid analgesics?

The most common side effect of opioid analgesics is constipation. This occurs due to the opioids' action on the gastrointestinal (GI) tract, where they bind to opioid receptors located in the wall of the intestines. This binding results in decreased peristalsis and slower transit time in the bowel, leading to constipation. The risk of developing constipation is significant, often requiring proactive management, such as the use of stool softeners or laxatives, especially in patients who are on long-term opioid therapy.

While nausea, drowsiness, and vomiting are also side effects associated with opioid use, constipation stands out as the most prevalent issue reported among patients. This is a crucial aspect of patient education and management when prescribing these medications, as addressing constipation can significantly improve patient comfort and adherence to opioid therapy.