EFFICACY AND SAFETY OF TRAMADOL HCL IN BREAKTHROUGH MUSCULOSKELETAL PAIN ATTRIBUTED TO OSTEOARTHRITIS

Objective. To evaluate the efficacy of tramadol as adjunctive therapy in patients with musculoskeletal pain attributed to osteoarthritis (OA ) who experienced breakthrough pain while taking a nonsteroidal antiin flammatory drug (NSAID).Methods. This single center, parallel, placebo controlled, 2 phase study was conducted in adults who experienced bre akthrough OA pain while undergoing stable NSAID therapy. In a 24 h ope n label phase, patients took 100 mg of tramadol followed by 50 mg ever y 6 h (total 250 mg) in addition to their daily NSAID regimen. Supplem ental analgesics were prohibited. Patients who met entry criteria and were willing to continue therapy were randomized to a 13 day double bl ind phase of adjunctive therapy with tramadol (50-100 mg every 4-6 h a s needed for pain) or placebo; NSAID therapy was continued. The primar y efficacy endpoint was the time to exit from the study because of the rapeutic failure (i.e., insufficient pain relief or an inability to pe rform activities of daily living).Results, The time to exit from the s tudy because of insufficient pain relief tended to be longer in the tr amadol group (250 mg/day) compared with the placebo group (p = 0.066). At the end of the double blind phase, pain at rest was significantly less severe in tramadol treated patients (p = 0.046). In addition, sev erity of pain on motion tended to be less severe in tramadol treated p atients (p = 0.059). General severity of current pain and ability to p erform activities of daily living were not significantly different wit h tramadol or placebo. Patients' overall assessment of therapy (p = 0. 022) and investigator's rating of global improvement (p = 0.004) were significantly better with tramadol than with placebo. Conclusion, Tram adol may have a role as adjunctive treatment for breakthrough pain in patients receiving NSAID therapy for musculoskeletal pain attributed t o OA.