The Relative Potency of Oral Transmucosal Fentanyl Citrate Compared with Intravenous Morphine in the Treatment of Moderate to Severe Postoperative Pain

Abstract
The relative potency of oral transmucosal fentanyl citrate (OTFC) to IV morphine was 8–14:1. In this postoperative setting, OTFC produced rapid pain relief similar to that produced by IV morphine. The larger doses of OTFC (800 μg) and morphine (10 mg) produced better and more sustained analgesia than 200 μg of OTFC or 2 mg of morphine.