Monotherapy with the norepinephrine reuptake inhibitor reboxetine alone reduces obstructive sleep apnea (OSA) severity.

Until now, and as previously reported in the limbic [link here], the evidence for benefit from noradrenergic agents in OSA was when they were combined with an antimuscarinic such as hyoscine.

Now, a small Australian double-blind, crossover study of 16 patients with OSA compared reboxetine alone or in combination with oxybutynin.

The study, published in the Journal of Clinical Sleep Medicine [link here], found reboxetine reduced the apnea-hypopnea index (AHI-primary outcome) by 5.4 [95% CI -10.4 to -0.3] events/h, P=0.03 (-24 ± 27% in men; -0.7 ± 32% in women).

Reboxetine alone also reduced the 4% oxygen desaturation index by (mean ± SD) 5.2 ± 7.2 events/h and reboxetine+oxybutynin by 5.1 ± 10.6 events/h versus placebo, P=0.02. Nadir oxygen saturation also increased by 7 ± 11% with reboxetine and 5 ± 9% with reboxetine+oxybutynin versus placebo, P=0.01.

The addition of oxybutynin did not result in additional improvements in AHI or oxygen saturation.

The authors, from Flinders University, the University of NSW and the University of Sydney, said the findings offered promise especially for the many people with OSA unable to tolerate current therapies such as CPAP.

“The current gold-standard treatment of sleep apnoea is with a CPAP device during sleep. But this one-size-fits-all approach doesn’t address the fact that there are different causes for sleep apnoea. In addition, many people can’t tolerate CPAP in the long term,” said lead author Dr Thomas Altree from the Flinders Health and Medical Research Institute.

“It’s therefore important we discover other avenues to assist people, and this study provides an important step for future drug development.”

The study also found that, mechanistically, reboxetine improved pharyngeal collapsibility and respiratory control.