This is a single center, open label, randomized, parallel group single dose intravenous (i.v.) administration study. The subjects will be randomized to receive a single dose of OxyNorm® 2.5, 5, and 10mg.

After up to 7 days screening period, Eligible Patients will be randomized to 1 of 3 groups, and begin treatment with single dose of OxyNorm® 2.5,5, and 10mg.

Inclusion Criteria:

• Patients with tumor pain / postoperative pain, or subjects with pain caused by other diseases;
• Patients aged >30 to ≤ 60 years;
• Body weight ≥ 45kg, and BMI range ≥19, <24;
• Karnofsky score ≥ 70;
• Expected survival is above 3 months;
• The results of liver function and kidney tests must meet the following criteria:ALT、AST is within the upper limit of normal value ranges by a factor 2, and TB、BUN、Cr is within the upper limit of normal value ranges by a factor 1.25;
• The electrocardiogram examination results are normal;
• Patients must have given a written informed consent prior to this trial, and have the capability to complete every required test.

Exclusion Criteria:

• Have hypersensitivity history to any opioids;
• Have known hypersensitivity to any of compositions of the study drugs;
• Patients who are likely to have paralytic ileus or acute abdomen or to perform an operation on abdominal region；
• Patients with respiratory depression, cor pulmonary, or chronic bronchial asthma;
• Patient unable to stop taking monoamine oxidase inhibitor during this trial period or time lapses less than 2 weeks since drug withdrawal;
• Patients with hypercarbia;
• Patients with biliary tract diseases, pancreatitis, prostatic hypertrophy, or corticoadrenal insufficiency;
• Patients with alcoholism or drug abuse history;
• Positive ant-HIV or syphilis antibody test result;
• Urine screening before study is positive for the opioids, barbiturates, amphetamines, cocaine metabolites, methadone, diazepam and cannabinoids;
• Donated 400 mL or more of blood or blood products within 3 months prior to the start of the study, or donated 200 mL or more of blood or blood products within one month prior to the start of the study.
• Subjects who participated in a clinical research study within two months of study entry.
• Patients who are currently taking opioids.