Postoperative pain control with a new transdermal fentanyl delivery system: A multicenter trial

Background: A new transdermal delivery system for fentanyl is available in two strengths: 70-80 and 90-100 μg · kg^-1 · h^-1 (40- and 60-cm² patches, respectively). Their short onset and 24-h drug delivery make them attractive for post-operative pain control. Methods: Both doses of the new transdermal fentanyl patches were evaluated for the relief of postoperative pain in 143 patients after gynecologic exploratory laparotomy. The study was conducted at four centers using a prospective, randomized, placebo- controlled, double-blind format. Patients were randomly assigned to one of three study groups: group 1 patients received two placebo patches; group 2 patients received a 40-cm² fentanyl patch and a 60-cm² placebo patch; and group 3 patients received a 60-cm² fentanyl patch and a 40-cm² placebo patch. Patient-controlled morphine use and pain, sedation, and comfort scores were assessed postoperatively every 4 h for 36 h after patch placement. Results: Patients' assessment of their analgesia was significantly (P ≤ 0.05) better in group 2 at 16 and 24 h and in group 3 at 8, 12, 16, 20, and 24 h postoperatively, compared with the patients in group 1. Patients in groups 2 and 3 required less supplemental morphine to maintain satisfactory analgesia than did the patients in group 1. Patients in groups 2 and 3 had greater incidences of pruritus, erythema, and respiratory depression than did those receiving placebo. Conclusions: Concern exists regarding the side effects of this this new transdermal fentanyl patch. Therefore, this new patch will need further research before it can be recommended as an adjunct in controlling postoperative pain.