What is a common side effect of opioid analgesics?

Opioid analgesics are widely used for pain management, but they are also known to produce a range of side effects due to their action on the central nervous system and gastrointestinal tract. Nausea and vomiting are particularly common side effects associated with opioids. This occurs because opioids can trigger the chemoreceptor trigger zone (CTZ) in the brain, which is responsible for the sensation of nausea and the act of vomiting. The effects can vary from mild to severe, depending on the individual and the specific opioid used.

The other options are less commonly linked to the use of opioid medications. Increased appetite is not typically associated with opioids; in fact, they can often lead to anorexia due to their other side effects. Hypertension is not a standard effect of opioid analgesics; they more commonly result in hypotension. Insomnia can be affected in various ways, but it is not a direct or common side effect linked to opioids specifically, as they often have a sedative effect. Thus, nausea and vomiting stand out as a notable and expected side effect among users of opioid analgesics.