Monitoring for Side Effects in Opioid Therapy

A 68-year-old male patient is admitted to the hospital with severe osteoarthritis and reports persistent pain, rated as 8 out of 10 on the pain scale. The healthcare provider prescribes an opioid analgesic to manage his pain. As the nurse, you are responsible for administering the medication and monitoring for potential side effects. Which of the following side effects should you closely monitor for in this patient due to his age and medication therapy?