Effect of Prophylactic Fentanyl Buccal Tablet on Episodic Exertional Dyspnea: A Pilot Double-Blind Randomized Controlled Trial.

CONTEXT: Episodic dyspnea is one of the most common, debilitating, and difficult-to-treat symptoms.

OBJECTIVE: We conducted a pilot study to examine the effect of prophylactic fentanyl buccal tablet (FBT) on exercise-induced dyspnea.

METHODS: In this parallel, double-blind randomized placebo-controlled trial, opioid-tolerant patients were asked to complete a six-minute walk test (6MWT) at baseline and then a second 6MWT 30 minutes after a single dose of FBT (equivalent to 20-50% of their total opioid dose) or matching placebo. We compared dyspnea Numeric Rating Scale (NRS, 0-10, primary outcome), walk distance, vital signs, neurocognitive function, and adverse events between the two 6MWTs.

RESULTS: Among 22 patients enrolled, 20 (91%) completed the study. FBT was associated with a significant within-arm reduction in dyspnea NRS between 0 and six minutes (mean change -2.4, 95% CI -3.5, -1.3) and respiratory rate (mean change -2.6, 95% CI -4.7, -0.4). Placebo was also associated with a nonstatistically significant decrease in dyspnea (mean change -1.1). Between-arm comparison of dyspnea scores in the second 6MWT favored FBT, albeit not statistically significant (estimate -0.25, P = 0.068). Global impression revealed more patients in the FBT group than placebo group reporting their dyspnea was at least "somewhat better" in the second 6MWT (4 of 9 vs. 0 of 11, P = 0.03). The other secondary outcomes did not differ significantly between arms.

CONCLUSIONS: This study supports that prophylactic FBT was associated with a reduction of exertional dyspnea and was well tolerated. Our findings support the need for larger trials to confirm the therapeutic potential of rapid-onset opioids.