The purpose of this study is to determine whether sublingual Buprenorphine is as effective as Iv Morphine sulfate on pain control of the patients with acute renal colic in the emergency department.

Inclusion Criteria:

• clinical diagnosis of acute renal colic; positive urinalysis of hematuria; pain score more than 3 in Numerical Rating Score (NRS); patients sign the informed consent to enroll.

Exclusion Criteria:

• previous history of seizures; cardiovascular, hepatic, renal or metabolic diseases;
• febrile patients (T > 38°C);
• hemodynamically unstable patients ( Systolic Blood Pressure < 90 mmHg);
• pregnant patients;
• patients with abdominal tenderness as a sign of peritoneal inflammation;
• any clinical suspicion for diseases other than urolithiasis like abdominal aortic aneurysm or dissection;
• patients with a history of drug addiction or known allergy to opioids;
• patients who had used analgesics 6 hours before arriving.