To compare the efficacy of oxycodone and morphine sulfate a double blinded, randomized, clinical trial study will be done. After obtaining informed consent, forty adult patients with acute lower limb trauma who are eligible for this study will be randomized to two groups. The control group will receive 5 milligrams of morphine sulfate intravenous injection and placebo tablet and the intervention group will receive 5 milligrams oxycodone hydrochloride tablet and placebo injection. Pain severity will be assessed by NRS (Numerical pain Rating Scale) scoring system. At times 0, 30' , 60' of analgesic administration pain severity, vital signs and adverse effects of analgesics such as lethargy, nausea, vomiting and itching will be assessed and registered in data collection sheets. All patients older than 14 years old with acute lower limb trauma who are admitted to Emergency department of Imam Hospital could be eligible for study however patients with past history of allergy to opioid, chronic renal/respiratory/liver disease, recent use of opioid, altered mental state, head trauma and pregnant patients will be excluded from study. SPSS software will be used for data analysis.