Millions of people abandon CPAP therapy every year. A repurposed epilepsy drug could offer a simpler solution.
Obstructive sleep apnoea affects hundreds of millions of people worldwide, causing repeated breathing interruptions during sleep that raise the risk of heart disease, high blood pressure, and stroke. The most effective treatment, a CPAP machine that delivers pressurised air through a mask, works well, but studies suggest up to half of patients stop using the device within a year because the mask can feel uncomfortable or interfere with sleep (The Week, 2026).
New results from a European clinical trial are offering hope of an alternative. Researchers tested sulthiame in 298 people with moderate to severe obstructive sleep apnoea across four European countries, in a randomised, double-blind, placebo-controlled trial (The Week, 2026).
Patients receiving higher doses of sulthiame experienced up to 47% fewer breathing interruptions during sleep compared to those given a placebo, and also showed improved overnight oxygen levels (The Week, 2026). The drug appears to work by stabilising the body’s control of breathing and increasing respiratory drive, reducing the likelihood that the upper airway will collapse during sleep (ScienceDaily, 2026).
The FLOW study evaluated three dosages, 100 mg, 200 mg, and 300 mg, administered once daily at bedtime over 15 weeks (Apnimed, 2025). Side effects increased with higher doses, suggesting 200 mg may represent the best balance of benefit and tolerability (ScienceAlert, 2026).
Lead researcher Jan Hedner from the University of Gothenburg described the results as a breakthrough, while stressing that larger and longer studies are still needed before the drug becomes widely available for sleep apnoea patients (ScienceDaily, 2026).
Published in The Lancet, these findings mark a significant step towards the first pill-based treatment that directly addresses the root cause of obstructive sleep apnoea.
References
Apnimed (2025) Apnimed announces publication in The Lancet of positive phase 2 results demonstrating sulthiame’s efficacy in obstructive sleep apnea. Available at: https://apnimed.com/article/apnimed-announces-publication-in-the-lancet-of-positive-phase-2-results-demonstrating-sulthiames-efficacy-in-obstructive-sleep-apnea/ (Accessed: 27 April 2026).
Randerath, W., Hedner, J. et al. (2025) ‘Sultiame once per day in obstructive sleep apnoea (FLOW): a multicentre, randomised, double-blind, placebo-controlled, dose-finding, phase 2 trial’, The Lancet, 406(10504), p. 665. doi: 10.1016/S0140-6736(25)01196-1.
ScienceAlert (2026) Repurposed drug improves sleep apnea by up to 50% in clinical trial. Available at: https://www.sciencealert.com/repurposed-drug-improves-sleep-apnea-by-up-to-50-in-clinical-trial (Accessed: 27 April 2026).
ScienceDaily (2026) Scientists may have found a pill for sleep apnea. Available at: https://www.sciencedaily.com/releases/2026/03/260311004816.htm (Accessed: 27 April 2026).
The Week (2026) Sleep apnea breakthrough: clinical trial finds drug sulthiame may reduce night-time breathing pauses. Available at: https://www.theweek.in/news/health/2026/03/16/sleep-apnea-breakthrough-clinical-trial-finds-drug-sulthiame-may-reduce-night-time-breathing-pauses.html (Accessed: 27 April 2026).
