Effect of local administration of transdermal fentanyl on peripheral opioid analgesia

Objective. Transdermal fentanyl is a commonly used analgesic for the treatment of severe chronic pain. Recent investigations have shown the presence of mu-opioid receptors in the skin and opioid analgesic efficacy with alternative routes of administration of narcotics. This placebo-controlled, double-blind prospective study assessed whether transdermal fentanyl administration produces local peripheral opioid analgesia at the site of application. Design. Baseline pain threshold and supra-threshold pain intensity assessments were measured using Quantitative Sensory Testing in 12 healthy volunteers. Placebo and fentanyl containing patches (Duragesic®, 25 μg/h) were applied to opposite forearms for 2 h. After patch removal, pain threshold, supra-threshold pain response, and the area of secondary hyperalgesia were evaluated for both forearms. Results. No statistically significant differences in pain threshold, supra-threshold pain intensity, or area of hyperalgesia in fentanyl- versus placebo-treated forearms were detected in the study subjects. Conclusion. These results suggest that the application of transdermal fentanyl patch for a period of 2 h does not produce local peripheral opioid analgesia at the site of patch application.