Sublingual administration of fentanyl to cancer patients is an effective treatment for breakthrough pain: results from a randomized phase II study

In this study we evaluated the efficacy and tolerability of sublingual fentanyl (SLF) for breakthrough pain (BTP) in adult opioid-tolerant cancer patients. Patients received one dose of placebo, SLF 100, 200 and 400 mu g in random order at four pain episodes. The primary efficacy endpoint was pain intensity difference (PID) from baseline. Twenty-seven patients received study medication. Overall PID increased significantly with SLF 400 mu g versus placebo (8.57 mm, p < 0.0001). Improvements were statistically different from placebo at 15 min (p = 0.005). SLF 100 and 200 mu g showed a numerical trend towards improved pain relief. A dose that gave a clinically important reduction in pain (PID > 20 mm) was identified by 95% of patients. Reduced use of rescue medication (p < 0.001, SLF 400 mu g) and improved global assessment of treatment (p = 0.0146, SLF 400 mu g) confirmed these differences as clinically important. Nausea and dizziness were the most common treatment-related adverse effects. SLF appears to be a fast, effective and well-tolerated treatment for BTP.