MULTICENTER TRIAL COMPARING TRAMADOL AND MORPHINE FOR PAIN AFTER ABDOMINAL-SURGERY

Seventy patients (40 male, 30 female), mean (SD) age 60.8 +/- 13.7 yea rs were treated with parenteral morphine (10 mg/1 ml ampul) or tramado l (100 mg/2 ml ampul) to verify their analgesic effects in pain follow ing abdominal surgery. This multicenter trial followed an open, contro lled experimental design between patients, randomized within the cente rs. The drugs were given by intramuscular injection, as requested by p atients, starting in the postoperative period when pain was more than 70 mm, assessed on a visual analog scale. Patients were allowed up to six ampuls of tramadol or morphine in the 24-h trial but in the first 4 h, if they asked for supplementary analgesic, only diclofenac (75 mg in a 3-ml ampul) was allowed. Both test drugs gave rapid and constant pain relief. After the first dose, pain intensity was reduced 36.2% w ith tramadol, and 51% with morphine; the pain-free interval was simila r for both treatments. The quality of sleep and the number of hours of sleep the night after surgery were similar for both groups. Tramadol was tolerated better, giving rise to no untoward reactions; with morph ine there was one case of mild respiratory depression. In abdominal su rgery, therefore, tramadol given by intramuscular injection has postop erative analgesic activity similar to morphine, but is better tolerate d.