Caution: sedation, confusion and delirium nausea and vomiting, constipation pruritus, retention, and respiratory depression are the most side effects encountered in the clinical use of opioids When evaluating for opiods-related side effects, clinician should distinguish Whether the side effects are due to the opioids, other drugs, or the disease progressionCaution:sedation, confusion and delirium, nausea and vomiting, constipation, pruritus, retention, and respiratory depression are the most side effects encountered in the clinical use of opioids. When evaluating for opiods-related side effects, clinician should distinguish whether the side effects are due to the opioids, other drugs, or the disease progression