A Two-Arm Study Comparing the Analgesic Efficacy and Safety of Acetaminophen and Tramadol Combination BID Versus Placebo for the Treatment of Acute Low Back Pain

• Males or females in generally good health aged 18-80 years with moderate to severe acute low back pain.
• Current acute low back pain episode within 48h prior to study entry.
• Pain must be moderate to severe following incident

Exclusion Criteria:

• Chronic low back pain
• Ongoing or history of alcohol or drug abuse
• Body Mass Index greater 39
• Treatment within the last 3 weeks with monoamine oxidase inhibitors; tricyclic antidepressants and other tricyclic compounds; neuroleptics; selective serotonin reuptake inhibitors
• Known history or symptoms suspicious for cancer
• Significant renal or liver disease
• Spinal surgery within 1 year of study entry.
• Subjects who are pregnant or lactating.
• Subjects with unstable medical disease.
• Subjects who have received treatment with an investigational product/device with 30 days prior to study entry.