Drug found to reduce sleep apnoea severity

Targeting a condition suffered by nearly a billion people worldwide, a new study from Flinders University has shown that a drug previously used to treat depression can reduce obstructive sleep apnoea severity. The authors of the study, published in the Journal of Clinical Sleep Medicine, say their work opens up further avenues for the development of future drug treatments targeted at the huge number of people unable to tolerate current sleep apnoea therapies.

Obstructive sleep apnoea (OSA) is a condition whereby the throat muscles intermittently collapse and block the airway during sleep, causing breathing to stop and start and the brain to be deprived of oxygen (hypoxia). In addition to causing poor-quality sleep at night and sleepiness during the day, a study from The University of Queensland (UQ) recently found a link between OSA and an increased risk of developing dementia; when researchers induced hypoxia in mice, they found this caused the same selective degeneration of neurons that characteristically die in dementia.

The current gold standard treatment for OSA is a continuous positive airway pressure (CPAP) machine, which keeps the airway open during sleep and allows oxygen to the brain; indeed, the UQ researchers are now recommending CPAP machines to help elderly OSA patients to maintain cognitive function. But Dr Thomas Altree, lead author on the Flinders study from FHRMI: Sleep Health, noted that this “doesn’t address the fact that there are different causes for sleep apnoea” and that “many people can’t tolerate CPAP in the long term”, so it is important to explore other avenues.

“Recent research found a combination of the medicines reboxetine and oxybutynin, which were both previously used for unrelated conditions, could be an effective treatment for obstructive sleep apnoea but can cause side effects,” Altree said.

“We wanted to see if reboxetine on its own could be effective and assess exactly how it changes breathing during sleep.”

The team ran a double blind, placebo-controlled, randomised, multicentre crossover trial with collaborators at the Woolcock Institute of Medical Research (following a gold standard for drug trials) with 16 people who had OSA. They tested single doses of reboxetine compared to a combination of reboxetine and oxybutynin or placebo. Their findings present evidence that reboxetine alone reduces OSA severity and provide further insight into the role of norepinephrine reuptake inhibitors on upper airway stability during sleep.

“We found the drug reduced the number of sleep apnoea events per hour and also improved oxygen levels, while the addition of oxybutynin didn’t cause additional improvements,” Altree said.

“We also used a state-of-the-art computing method to determine how the drug stabilises breathing during sleep, which allows us to identify which patients might benefit most from the drug in the future.”

Image credit: iStock.com/nicolesy

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