Opioids have long served as the first-line analgesics for patients suffering from acute renal colic (RC). The two most-studied and most commonly used opioids for the ED treatment of RC are morphine and meperidine. The NSAIDs are believed to reduce RC-associated pain by inhibiting prostaglandin synthesis and release. Comparison of morphine (5 mg IV, repeated after 20 min), ketorolac (15 mg IV, repeated after 20 min), and combination of both, found that dual therapy provides significantly better pain relief than either drug alone. The combination of morphine plus ketorolac was also associated with a decreased requirement for rescue analgesia. Given the fact that most ureteral stones are small enough to pass spontaneously, it is thought that diuretics (with or without IV fluid therapy) might relieve RC pain by facilitating movement of the stone into the bladder.