Effect of multifaceted intervention promoting early switch from intravenous to oral acetaminophen for postoperative pain: controlled, prospective, before and after study.

Problem: Need to improve the efficiency of postoperative pain management by early switching from intravenous to oral acetaminophen.

Design: Implementation of local guidelines aimed at improving nurses' and doctors' behaviour. A controlled, prospective, before and after study evaluated its impact on appropriateness and costs.