COMPARISON OF TRAMADOL WITH MORPHINE FOR POSTOPERATIVE PAIN FOLLOWINGABDOMINAL-SURGERY

In a multi-centre, double-blind, randomized study involving 523 patien ts, the analgesic efficacy of tramadol was compared to that of morphin e given in repeated intravenous boluses as required to control post-op erative pain following abdominal surgery over 24 h. Intravenous admini stration of the study analgesic started as soon as the patient reporte d pain. Patients received an initial dose (either tramadol 100 mg or m orphine 5 mg) and, if necessary, repeat doses of tramadol 50 mg or mor phine 5 mg could be given on demand over the first 90 min. Further dos es up to a total of tramadol 400 mg or morphine 40-mg could then be gi ven after 90 min up to 24 h after the first dose of study medication. The primary efficacy parameter was the responder rate (no or slight pa in) within the first 90 min of treatment. Whilst responder rates reach ed 72.6% with tramadol and 81.2% with morphine, the treatments were st atistically equivalent and the observed difference in the responder ra tes between the groups was within the predefined range of +/- 10%. Mea n cumulative doses received by treatment responders amounted to 188.2 mg within the first 1.5 h and 157.1 mg during the subsequent 22.5 h in the tramadol group and 13.9 and 18.4 mg, respectively, in the morphin e group. A high incidence of gastrointestinal adverse events were obse rved with both treatments mostly consisting of mild nausea, dry mouth, vomiting, dyspepsia and hiccups.