Nebulized Fentanyl in Patients With Mild to Moderate Interstitial Lung Disease and Chronic Dyspnea

Treatment with opioids can improve activity related dyspnea by reducing central respiratory neural drive. Inhaled fentanyl citrate is an opioid that is generally well tolerated and has been shown to effectively relieve respiratory discomfort without causing systemic side-effects, although its mechanism of action are poorly understood. Based on the current evidence, non-sedating, rapidly active inhaled fentanyl represents a possible alternative and effective treatment of severe dyspnea in patients with ILD who require urgent treatment. As such, the primary objective of this study is to examine the acute effects of nebulized fentanyl on dyspnea intensity and quality in patients with mild-to-moderate ILD, as well as examine the neurophysiological mechanisms of dyspnea relief during fentanyl inhalation. It is believed that fentanyl when compared with placebo, will reduce inspiratory neural drive to the diaphragm and breathing frequency, resulting in improvements in dyspnea intensity during physical exertion. Alternatively, dyspnea relief after inhaled fentanyl may be independent of changes in neural drive, and instead linked to the presence of opioid receptors in the lungs that modulate afferent inputs to the brain, thereby favourably influencing perceived dyspnea.