Combination Upper-Airway Electrical and Pharmacological Stimulation for Obstructive Sleep Apnea

Residual obstructive sleep apnea (OSA) is common among patients treated with hypoglossal nerve stimulation (HGNS), reflecting incomplete correction of underlying pathophysiological traits. In addition to upper airway collapsibility, non-anatomical factors such as a low arousal threshold may contribute to persistent disease despite HGNS therapy. Pharmacologic modulation of these traits represents a potential strategy to enhance treatment efficacy. Atomoxetine (a norepinephrine re-uptake inhibitor) and oxybutynin (an anti-muscarinic agent) have been shown to increase upper airway muscle tone and raise the arousal threshold, leading to reductions in OSA severity in prior studies. However, their combined effect when added to ongoing HGNS therapy has not been systematically evaluated. This study is a randomized, placebo-controlled, crossover trial designed to assess the acute effects of combined pharmacologic and electrical stimulation on OSA severity. Participants with OSA who are already implanted with HGNS, or pending clinical implantation, will be enrolled in a four-period randomized placebo-controlled cross-over trial assessing HGNS+AtoOxy, HGNS alone (plus placebo), AtoOxy alone (HGNS device off), and placebo (HGNS device off). The main goal is to determine whether the combined treatment reduces the number of breathing events during sleep; the primary outcome test will compare HGNS+AtoOxy versus HGNS alone. The effect of each intervention versus placebo will also be presented. Polysomnographic measurements will be also be used to explore mechanisms underlying response, including the interaction between pharmacologically modifiable traits and HGNS-mediated airway stabilization. Additional analyses will evaluate whether baseline physiological characteristics predict treatment response, with the goal of informing personalized treatment strategies for patients with residual OSA. Patient-reported outcomes, including sleepiness, sleep-related quality of life, fatigue, and treatment satisfaction, will also be assessed to evaluate the broader clinical impact of the combination intervention.