a pharmacodynamic/pharmacokinetic study to determine the onset of analgesic effect and plasma levels of tramadol in patients with acute low back pain receiving a single 200 mg dose of tramadol contramid® once-a-day

Conditions: Acute Low Back Pain

Summary: the primary objective of this study is to determine the time of onset of analgesic effect of tramadol contramid® once-a-day (oad) in acute low back pain. secondary objectives include determining the relationship between analgesic effect and plasma levels for tramadol contramid® oad and to examine safety after single dose administration of 200 mg of tramadol contramid® oad.


Eligibility criteria:
inclusion criteria: * males or females in generally good health aged 18-80 years with acute low back pain are eligible for this study. * patients must have pain of moderate to severe intensity on the patient rating of pain intensity scale without analgesia. * oral and written language comprehension at a level sufficient to comply with the protocol and complete study-related materials. * must have signed and dated an reb-approved written informed consent form which was also signed and dated by the investigator prior to study participation. exclusion criteria: * known history or symptoms suspicious of: * spinal fracture * cancer (i.e. constitutional symptoms such as recent unexplained chills or weight loss) * spinal infection (e.g. iv drug abuse, immunosuppression) * cauda equina syndrome * spina bifida * foot drop * spinal surgery within 1 year of study entry * body mass index (bmi) \> 37 * continuous chronic back pain * more severe pain in a region other than the lower back * treatment of the back pain with non-pharmacological therapy (e.g. acupuncture chiropractic adjustment, transcutaneous electrical nerve stimulation, physiotherapy etc.) in the 3 weeks prior to study entry * use of any sedative hypnotics, topical preparations/medications and anaesthetics or muscle relaxants within 5 half-lives of the dose of study medication * use of any analgesic within 6 hours of the dose of study medication. in rare cases, if a patient is in moderate to severe pain despite having taken a short-acting analgesic and if at least 2 hours have passed since the dose of short-acting analgesic, the patient may be entered. * a major illness, requiring hospitalisation during the 3 months before commencement of the screening period * unwillingness to stop taking pain medication other than the study medication * previous failure of treatment with tramadol or discontinuation of treatment with tramadol due to adverse events * treatment within the last 3 weeks with any of the following medications: monoamine oxidase inhibitors; tricyclic antidepressants and other tricyclic compounds (e.g. cyclobenzaprine, promethazine); neuroleptics; selective serotonin reuptake inhibitors (ssris); serotonin-norepinephrine reuptake inhibitors (snris) or any other drug that reduces seizure threshold * treatment with another investigational agent within the last 30 days * history of seizure disorder other than infantile febrile seizures * previous or current opioid dependency * bowel disease causing malabsorption * pregnant or lactating women * known significant liver disease or symptoms of significant liver disease * known significant renal disease or symptoms of significant renal disease * current or past substance abuse or dependence, other than nicotine * allergy to tramadol or any structurally similar drugs (e.g. opiates) * any other condition that, in the opinion of the investigators, would adversely affect the patient's ability to complete the study or its measures

Keywords: back pain