Efficacy of sublingual fentanyl vs. oral morphine for cancer-related breakthrough pain.

Introduction: Breakthrough cancer pain (BTcP) is recognized as a clinically significant complication of chronic cancer pain with most BTcP episodes peaking in intensity within a few minutes and lasting for approximately 30 min. Although a number of rapid-onset fentanyl preparations have been developed in the last decade, BTcP is still typically managed through the use of rescue doses of oral morphine but a comparative study of sublingual fentanyl and oral morphine is still lacking. The aim of this study was to determine the efficacy, tolerability, and patient satisfaction of sublingual fentanyl citrate (SLF) and oral morphine solution (OM) in the treatment of BTcP.

Methods: In this prospective, longitudinal, controlled-study, 40 patients with BTcP were allocated to receive oral morphine (OM) or sublingual fentanyl (SLF). Pain intensity level on a 0-10 numerical rating visual analog scale (VAS), frequency of BTcP throughout the day, onset of relief (0-5, 6-10, 11-15, or over 16 min), time required for dose titration, patient satisfaction and adverse effects were assessed at 3, 7, 15, and 30 days after starting the treatment.

Results: Mean doses of opioids for BTcP were 235 ± 23.4 μg (SLF) and 38 ± 5.2 mg (OM). The mean pain intensity levels were significantly lower with SLF than OM at 3 days (6.0 vs. 6.95; p = 0,001), 7 days (4.15 vs. 6.25, p < 0.001), 15 days (3.45 vs. 5.35, p < 0.001), and 30 days (3.05 vs. 4.45, p < 0.001). SLF provided significantly faster relief for BTcP than OM (p < 0.001) with a shorter dose titration period (mean 6.6 ± 3.3 vs. 13.3 ± 4.9 days; p < 0.001) and better satisfaction scores and with a very good safety profile.

Conclusions: Administration of SLF might provide a more effective treatment option than oral morphine for BTcP.