RESUMO
The dose of a transdermal fentanyl patch is proportional to its application site area. Therefore, the absorption of fentanyl may decrease if the patch detaches, leading to insufficient analgesia. Sixteen healthy volunteers were enrolled in a study to investigate the appropriate application sites and clinical utility of three transdermal fentanyl patches available in Japan. Three placebos, Fentanyl 1-day (Fentos; Fen), Fentanyl 3-day (Durotep; Dur), and Generic Fentanyl 3-day (HMT) were administered using a crossover study design. The placebos were applied to 11 different sites, including both sides of the upper arm, abdomen, back, thigh, chest, and the middle of the chest. We determined the patch detachment area and incidence of patch-induced itching every 24 h and evaluated differences between each application site using the Wilcoxon signed-rank test. Significant patch detachment was observed on the abdomen and upper arms with Fen, on the abdomen and chest with Dur, and on the chest with HMT compared with that at other sites (p<0.005). Although no significant difference in itching was observed between regions when administering Fen, itching significantly increased on the chest and back when using Dur and on the abdomen when using HMT as compared with that at other sites (p<0.05). Our results indicate that the three transdermal Fen patches exhibit different adhesive properties and local adverse events, indicating that the application site should be cautiously selected for each patch type.
