Transdermal fentanyl: acute analgesic clinical studies.

The transdermal therapeutic system (TTS) is a novel technique of drug administration that can mimic long-term continuous intravenous infusions in maintaining stable drug plasma concentrations. Fentanyl, a potent lipid-soluble synthetic opioid, has been incorporated into such a system and has undergone preliminary clinical trials in postoperative patient populations to assess analgesic efficacy and incidence of undesirable side effects (pruritus, nausea and vomiting, urinary retention, respiratory depression). In general, when applied 2 hr preoperatively, a TTS (fentanyl) patch (in different doses) provides moderate-to-good analgesia for a variety of surgical procedures for periods of up to 3 days. Most patients will require small amounts of systemically administered opioids for supplementary analgesia, especially in the first 24 postoperative hr. The incidence of side effects such as nausea and vomiting varies between studies but can be as high as 70%. Clinically significant respiratory depression is rare but was reported in several of the studies. TTS (fentanyl) is a simple and useful technique for the control of postoperative pain.