Which effect should a nurse monitor for a patient taking opioid analgesics?

When a patient is taking opioid analgesics, one significant effect that requires monitoring is shortness of breath. Opioids are known for their central nervous system depressant properties, which can lead to respiratory depression. This occurs because opioids can suppress the brain's ability to trigger the natural urge to breathe, especially at higher doses or in sensitive individuals such as those who are elderly or have pre-existing respiratory issues.

Monitoring for shortness of breath is crucial because this symptom may indicate the onset of respiratory failure, which is a serious and potentially life-threatening side effect of opioid therapy. Nurses need to pay close attention to the patient's respiratory rate and effort, as well as any signs of distress, to ensure timely intervention if respiratory complications arise.

In contrast, the other options—hyperactivity, increased alertness, and weight loss—are generally not associated with the effects of opioid analgesics. Opioids typically have sedative effects, thus making hyperactivity and increased alertness unlikely outcomes. Weight loss can occur in some cases due to a variety of reasons, but it is not a direct or common effect of opioid analgesics. Therefore, observing for shortness of breath is paramount when managing patients on these medications.