One of the most common side effects of the opioid narcotics is constipation. Other side effects include drowsiness, mental clouding, itching, inability to urinate, low blood pressure. Narcotic analgesics produce physical and psychological dependence. Most of these drugs have major side effects, including dose-related respiratory depression, apnea circulatory depression, respiratory arrest, coma, shock and cardiac arrest. Most frequent adverse effects are lightheadedness, dizziness, sedation, nausea, vomiting,