For nearly a billion people worldwide, sleep apnea means a nightly battle: hours strapped to a CPAP machine, struggling with masks that leak, hiss, and strangle restful sleep. Now, a repurposed epilepsy drug has shown it can reduce breathing interruptions by up to 47% — and the data just landed in one of medicine's most prestigious journals.
Results from the FLOW study, a Phase 2 randomised controlled trial published in *The Lancet*, found that sulthiame — a carbonic anhydrase inhibitor already used for decades in childhood epilepsy — significantly reduced both the frequency and severity of sleep apnea events in adults with moderate to severe obstructive sleep apnea (OSA). The findings were highlighted this week by ScienceDaily and have sent ripples through the sleep medicine community.
**The Numbers That Matter**
The trial enrolled 298 adult patients across 28 sites in five European countries — Spain, France, Belgium, Germany, and the Czech Republic. All participants had moderate to severe OSA, meaning they were stopping breathing at least 15 times per hour during sleep.
The results from the higher-dose sulthiame group were striking: - **Up to 47% fewer breathing pauses** compared to those on placebo - Significantly **improved blood oxygen levels** throughout the night - Reduced **daytime sleepiness** — one of the most debilitating symptoms of OSA - The drug was **generally well-tolerated**, with mostly mild, temporary side effects (pins and needles, headaches, fatigue)
**How It Works**
Sleep apnea happens when the muscles of the upper airway repeatedly relax and collapse during sleep, cutting off breathing. Current treatments — primarily CPAP machines that force air through a pressurised mask — are effective but notoriously difficult to tolerate. Up to half of patients abandon them within a year.
Sulthiame takes a completely different approach. Rather than splinting the airway open mechanically, it works by **stabilising the body's neurological control of breathing**. It blocks carbonic anhydrase enzymes, which increases carbon dioxide sensitivity, which in turn drives a stronger, steadier respiratory drive throughout the night. The result: the upper airway is less likely to collapse in the first place.
*"This represents a first-of-its-kind approach. We have never had a pill that meaningfully addresses the underlying breathing instability in sleep apnea."* — University of Gothenburg researchers
**Why This Is Such Big News**
Sleep apnea affects an estimated **936 million people worldwide** — roughly 1 in 8 people on Earth. It's associated with dramatically elevated risks of heart disease, stroke, type 2 diabetes, depression, and dementia. Yet the majority of sufferers go undiagnosed, and many of those who are diagnosed never achieve consistent treatment.
The core problem has always been CPAP compliance. The machines work beautifully in clinical studies — and are largely abandoned in real life. Dental appliances exist as a partial solution, but they're expensive, require specialist fitting, and work best for mild cases.
A pill that patients can simply take at bedtime would transform the field entirely.
**The Road Ahead**
Sulthiame is being developed for sleep apnea by Apnimed in collaboration with Japanese pharmaceutical company Shionogi. The FLOW study results have now cleared the bar for advancing to Phase 3 — the large-scale trials needed before any drug can be approved by regulators.
It is important to note that sulthiame is not yet approved for sleep apnea and is still an investigational therapy. Phase 3 trials will need to confirm the Phase 2 results in a larger population and across longer timescales before it can become a standard treatment option.
But the FLOW results are the clearest signal yet that the era of the CPAP machine as the *only* real treatment option for sleep apnea may be coming to an end — replaced by something that fits in your pocket.
For the nearly billion people who've wrestled with the mask and hose every night, that's very good news indeed. 💊😴
*Sources: ScienceDaily (March 11, 2026) · The Lancet Phase 2 FLOW Study · Apnimed press release · University of Gothenburg · AJMC · Neura Health*
