Buprenorphine in Acute Renal Colic Pain Management

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.