Reboxetine Plus Oxybutynin for OSA Treatment: A 1-Week, Randomized, Placebo-Controlled, Double-Blind Crossover Trial

The recent discovery that a combination of noradrenergic and antimuscarinic drugs improved upper airway muscle function during sleep and reduced OSA severity has revitalized interest in pharmacologic therapies for OSA.

Would 1 week of reboxetine plus oxybutynin (Reb-Oxy) be effective on OSA severity?

A randomized, placebo-controlled, double-blind, crossover trial was performed comparing 4 mg reboxetine plus 5 mg oxybutynin (Reb-Oxy) vs placebo in patients with OSA. After a baseline in-laboratory polysomnogram (PSG), patients underwent PSGs after 7 nights of Reb-Oxy and 7 nights of placebo to compare apnea-hypopnea index (AHI), which was the primary outcome. Response rate was based on the percentage of subjects with a ≥ 50% reduction in AHI from baseline. Secondary outcomes included Epworth Sleepiness Scale (ESS) score and psychomotor vigilance test (PVT) values. Home oximetry evaluated overnight oxygen desaturation index (ODI) throughout treatment.

Sixteen subjects aged 57 [51-61] years (median [interquartile range]) with a BMI of 30 [26-36] kg/m² completed the study. Reb-Oxy lowered AHI from 49 [35-57] events per hour at baseline to 18 [13-21] events per hour (59% median reduction) compared with 39 [29-48] events per hour (6% median reduction) with placebo (P < .001). Response rate for Reb-Oxy was 81% vs 13% for placebo (P < .001). Although ESS scores were not significantly lowered, PVT median reaction time decreased from 250 [239-312] ms at baseline to 223 [172-244] ms on Reb-Oxy vs 264 [217-284] ms on placebo (P < .001). Home oximetry illustrated acute and sustained improvement in the oxygen desaturation index on Reb-Oxy vs placebo.

The administration of Reb-Oxy greatly decreased OSA severity and increased vigilance. These results highlight potential possibilities for pharmacologic treatment of OSA.

ClinicalTrials.gov; No.: NCT04449133; URL: www.clinicaltrials.gov.