Transdermal Fentanyl Reduces Pain and Improves Functional Activity in Neuropathic Pain States

Abstract

The efficacy of transdermal fentanyl in chronic neuropathic pain has not been well studied. We examined the effects of transdermal fentanyl on pain and function in patients with chronic neuropathic pain states. A 16-week open-label study evaluated pre- and postdrug therapy effects. An actigraph was used to record pain scores (0-10) three times a day and activity level (8 am-8 pm) continuously. Pain scores were also entered in pain diary logs. The study was conducted on subjects visiting the Johns Hopkins Hospital as outpatients. Patients with peripheral neuropathic pain (N = 25), complex regional pain syndrome-1 (N = 19), and postamputation pain (N = 9) were enrolled in the study. After a 2-week baseline, transdermal fentanyl was titrated over 6 weeks with a dose of 25-150 microg/h based on individual response and then followed for an 8-week maintenance period. Average pain score and activity level were compared during the last week of the baseline and maintenance periods. Subgroup effects were also examined. Other outcome measures included pain relief (0-100%), cognition, affect, and impairment of function. Forty patients completed the study, and 13 withdrew at varying time points. The average dose for transdermal fentanyl was 105.6 microg/h. Significant reductions in pain (-2.94 +/- 0.27) and percent pain relief (33.7 +/- 14%) were observed. These reductions in pain were accompanied by a 37.4% average increase in daytime activity. Sedation and nausea/vomiting were the common side effects. No significant changes were observed in tests of cognition or affect. Overall, there was a significant reduction in pain intensity and increase in activity in neuropathic pain patients treated with transdermal fentanyl.