Atomoxetine and fesoterodine combination improves obstructive sleep apnoea severity in patients with milder upper airway collapsibility

The combination of the noradrenergic atomoxetine plus the anti-muscarinic oxybutynin acutely increased genioglossus activity and reduced obstructive sleep apnoea (OSA) severity. However, oxybutynin has shorter half-life than atomoxetine and side effects that might discourage long-term usage. Accordingly, we aimed to test the combination of atomoxetine and fesoterodine (Ato-Feso), a newer anti-muscarinic with extended release formulation, on OSA severity and endotypes.Twelve subjects with OSA underwent a randomized, double-blind, crossover trial comparing one night of atomoxetine plus fesoterodine (80-4 mg) to placebo. Parameters of OSA severity (e.g., apnoea-hypopnoea index [AHI], nadir oxygen desaturation and hypoxic burden) were calculated from two clinical, in-lab polysomnographic studies. OSA endotypes (including collapsibility per VCompared to placebo, Ato-Feso did not reduce the AHI (34.2 ± 19.1 vs. 30.1 ± 28.2 events/h, p = 0.493), but reduced the apnoea index (12.9 [28.8] vs. 1.8 [9.1] events/h, median [interquartile range], p = 0.027) and increased nadir desaturation (76.8 [8.0] vs. 82.2 [8.8] %, p = 0.003); a non-significant trend for improved hypoxic burden was observed (52.4 [50.5] vs. 29.7 [78.9] %min/h, p = 0.093). Ato-Feso lowered collapsibility (raised VWhile inefficacious in unselected patients, Ato-Feso administered for one night suppressed OSA in patients with milder collapsibility. Ato-Feso may hold some promise as an alternative OSA treatment in certain subgroups of individuals.