The Morphine-Sparing Effect of Propacetamol on Patient Controlled Analgesia in Gynecological Surgery

Han, Tae Hyung; Park, Chang Soo

Abstract

BACKGROUND: The efficacy and safety of propacetamol, an injectable prodrug of acetaminophen, in combination with morphine administered by patient controlled analgesia(PCA) were studied in 40 patients after gynecological surgery requiring lower abdominal incision.
METHODS
Using a double-blind, randomized, parallel-group design, the effects of four (every 6 hr) intravenous injections of 2 g propacetamol(=1 g acetaminophen) were compared with four injections of placebo in the recovery room immediately after surgery. Efficacy was assessed over 24hr by automated recording on the PCA device of the cumulative dose of morphine and the number of boluses requested. It was assessed on pain scores rated on a ten-point verbal scale, at 30 minutes, 1hr, 2hr, 4hr and then every 4hr until the 24hr after administration. Any side effects were recorded throughout the duration of the study, and the ability to tolerate the drug was assessed by recording of hemodynamic changes, patient satisfaction, the frequency of side effects and sedation scores at the predetermined time interval as above.
RESULTS
The 24-hr morphine consumption was significantly decreased in the propacetamol group. Analysis of the hourly morphine doses showed a significant decrease from the fourth hour. Although there was no significant difference in pain scores between the two groups, 80% of patients in the morphine group versus 85% of the propacetamol group found it "good" or "extremely good". The incidence of nausea was less in the propacetamol group. The incidence of other side effects were statistically insignificant.
CONCLUSION
Propacetamol has demonstrated a morphine sparing effects(=37%) in gynecological postoperative pain, thus confirming that it is a useful and safe injectable non-NSAID, nonopioid analgesic in postoperative period.