An Exploratory Study of Tramadol Hydrochloride in Patients With Osteoarthritis of the Knee or Low Back Pain

Since JNS013 is a combination of tramadol hydrochloride (TRAM) acting as a weak opioid with acetaminophen (APAP) inhibiting central COX-3, it is expected to have an intermediate effect between narcotic analgesics and NSAIDs (non-steroid anti-inflammatory drugs). This is a multicenter, open-label, dose response study. The purpose of this study is to find the clinical dose range of TRAM in patients with chronic pain due to osteoarthritis (OA) of the knee or low back pain (LBP) who cannot attain a sufficient analgesic effect from NSAIDs. The investigational product will be orally administered 4 times daily (after each meal and before bedtime) at a dose of 25 to 100 mg at least 4-hour intervals. Treatment will be started at an initial dose of 100 mg/day, and the dose is titrated by 25 mg every 7 days if the analgesic effect is insufficient and there is no problem with the safety. Treatment will be continued up to 35 days in total at a dose of 400 mg/day or a dose of which a sufficient analgesic effect can be obtained. The primary efficacy endpoint is the change in the intensity of pain from the beginning of dose-finding period (baseline) to the final assessment point (Up to Day 36), by using VAS (Visual Analog Scale). The safety evaluations are adverse events, laboratory examinations, blood pressure/pulse rate and body weight. Total study period of this study is 49days, Screening period is 7days, Administration period is 35 days and Follow-up period is 7 days. The investigational product will be orally administered 4 times daily (after each meal and before bedtime) at a dose of 25 to 100 mg at least 4-hour intervals. Treatment will be started at an initial dose of 100 mg/day, and the dose is titrated by 25 mg every 7 days if the analgesic effect is insufficient and there is no problem with the safety. Treatment will be continued up to 35 days in total at a dose of 400 mg/day or a dose of which a sufficient analgesic effect can be obtained.