What is a common side effect associated with opioid agonists?

Sedation is a well-recognized side effect associated with opioid agonists due to their central nervous system depressant effects. Opioids work by binding to specific receptors in the brain, leading to a reduction in pain perception and an overall calming effect, which often manifests as drowsiness or sedation. This sedative effect is one of the primary reasons opioids are effective for pain management, as they not only relieve pain but also help patients feel more relaxed.

Other options, while they may occur in certain circumstances, are not commonly associated with opioid use. Insomnia can be a result of various factors, but it is not a routine side effect of opioid agonists. High blood pressure is not typically caused by opioids; in fact, opioids can lead to decreased blood pressure in some cases due to their vasodilatory effects. Hair loss is not a recognized side effect of opioid therapy and is more frequently linked to other medical conditions or treatments. Thus, sedation remains the most common and expected side effect of opioids, making it the correct selection.