Analgesic efficacy of E2078 (dynorphin analog) in patients following abdominal surgery

: Studies were carried out to elucidate the efficacy and safety of E2078, a metabolically stable dynorphin analog, in patients with severe pain following lower abdominal surgery. E2078 was administered intramuscularly in a single dose of 1 to 15 mg. The efficacy was determined by evaluating the pain intensity score (PI) and global improvement rating (GIR) by the investigator. E2078 exhibited analgesic effect at doses of 10 mg or more. At the dose of 10 mg (n = 24). PI decreased from 3.0 to 1.3, and GIR was 83%. When the dose was increased to 12.5 mg (n = 15), PI improved from 3.0 to 1.3, and GIR was 100%. The improvement in PI, GIR and the duration of efficacy were 3.0 to 0.8, 100% and 6 hours 40 minutes with E2078 15 mg (n = 10), respectively. E2078 did not produce any adverse effects at doses of up to 15 mg. The results of the present study indicate that E2078 begins to exhibit analgesic effect at a dose of 10 mg, and at 15 mg its effect is comparable to that of pentazocine 15 mg.