What is a notable side effect of opioid use aside from pain relief?

Opioids are well-known for their effectiveness in managing pain, but they also come with a range of side effects due to their action on the central nervous system. One of the most serious and critical side effects of opioid use is respiratory depression. Opioids bind to specific receptors in the brain that not only modulate pain perception but also regulate respiratory functions. This can lead to a decrease in the drive to breathe, potentially resulting in bradypnea (slow breathing) and, in severe cases, respiratory arrest.

The risk of respiratory depression is particularly heightened in certain populations, including those who are opioid-naive, elderly, or have underlying respiratory conditions. This makes it essential for healthcare providers to monitor patients closely when prescribing opioids.

In contrast, the other options presented do not typically represent significant concerns associated with opioid therapy. For instance, while some gastrointestinal effects can occur, including constipation, diarrhea is more often associated with opioid withdrawal rather than their use. Headaches and weight gain may occur for various reasons but are not particularly characteristic of opioid side effects.