Patient description: A 58-year-old African-American woman presents to the ER with episodic pressing/burning anterior chest pain that began two days earlier for the first time in her life. The pain started while she was walking, radiates to the back, and is accompanied by nausea, diaphoresis and mild dyspnea, but is not increased on inspiration. The latest episode of pain ended half an hour prior to her arrival. She is known to have hypertension and obesity. She denies smoking, diabetes, hypercholesterolemia, or a family history of heart disease. She currently takes no medications. Physical examination is normal. The EKG shows nonspecific changes.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Pain Back Pain Low Back Pain Back Pain With Radiation At Visit 1 (study entry) patients must have a medical history and physical and neurological examinations that support a clinical diagnosis of acute low back pain that is felt down to the lower leg below the knee with the onset no longer than 30 days before Visit 1 At Visit 1 patients must report qualifying pain intensity scores Patients must be appropriate candidates for treatment with oral opioid pain medication in the investigator's clinical judgment Patients must be able to appropriately verbalize pain characteristics and to complete all protocol required measurements/assessments without assistance Patients must be medically stable on the basis of physical examination, medical history, vital signs, and clinical laboratory tests performed at screening  History of back (cervical, thoracic or lumbosacral) pain =50% of the time in the 1 year prior to the first visit History of any low back pain episode, with the exception of the current acute low back pain episode, within 3 months prior to the first visit that was greater than mild in pain intensity, or was associated with disability (e.g., loss of time from work, family, or activities of daily living), or necessitated the use of an opioid (narcotic) analgesic including tramadol Medical history or physical examination results that suggest the acute low back pain or any of the neurological symptoms or signs are caused by a serious medical condition (e.g., fever, chills, unexplained weight loss, bowel or urinary bladder dysfunction or incontinence, bilateral leg weakness, progressive weakness, paralysis) There is a high probability for surgical intervention for the back pain during the projected time on the study or that there will be an increase in the severity of the leg pain or deficits Had either a surgical procedure involving the spine or intervertebral discs in the lower back region within 1 year prior to Visit 1 or had >1 surgical procedure(s) involving the spine or intervertebral discs in the lower back region has any painful condition that could interfere with the study assessments or with the patient's ability to differentiate the pain associated with the acute low back pain episode from pain associated with another condition History of severe lumbar spinal stenosis, fibromyalgia, or ankylosing spondylitis history of epilepsy or recurrent seizures Unable or unwilling to discontinue all prohibited medications at the time of randomization and during the time of their participation in the study Known or suspected history of alcohol or drug abuse based on medical history, physical examination, urine drug screening, or the investigator's clinical judgment