sleep apnea drug research is tightening into focus after a European clinical trial found that people taking higher daily doses of sulthiame, an epilepsy medication, had dramatically fewer breathing interruptions during sleep. The stage II trial, led by researchers at the University of Gothenburg in Sweden and conducted across multiple European countries, tested several doses against a placebo and tracked overnight breathing outcomes. The push is urgent: many patients struggle to tolerate CPAP masks, and investigators say the results justify larger, longer studies to confirm durability of benefit and broader safety.
What the trial found, and why it matters now
Researchers at the University of Gothenburg tested sulthiame in adults diagnosed with moderate to severe obstructive sleep apnea, splitting participants into placebo and multiple dose groups. In one reported stage II trial design, a cohort of 240 participants was divided into four groups receiving placebo or 100 mg, 200 mg, or 300 mg of sulthiame daily; in another reported summary of the European trial, 298 people participated with one quarter receiving placebo and the remainder receiving different doses, using a double-blind approach in which neither participants nor researchers knew who received the active drug.
Across the trial reporting, the signal was consistent: higher doses were linked to marked reductions in breathing interruptions during sleep compared with placebo. Trial results described reductions in sleep apnea severity of about 30% to 50% at 200 mg or 300 mg in the dose-finding design, and up to 47% fewer breathing interruptions in the European trial summary. Participants taking sulthiame about an hour before bedtime also showed improved overnight oxygenation and reduced excessive daytime sleepiness versus placebo.
Investigators noted no clinically relevant safety concerns in the stage II dose-finding report, while also emphasizing that side effects increased with dose—positioning 200 mg as a potential “sweet spot” between benefit and tolerability.
Immediate reactions from the research team
Jan Hedner, senior professor of pulmonary medicine at the Sahlgrenska Academy, University of Gothenburg, described the findings in direct terms: “We have been working on this treatment strategy for a long time, and the results show that sleep apnea can indeed be influenced pharmacologically. ” He added: “It feels like a breakthrough, and we now look forward to larger and longer studies to determine whether the effect is sustained over time and whether the treatment is safe for broader patient groups. ”
Within the University of Gothenburg team, Ludger Grote and Kaj Stenlöf also made important contributions to the research, as described in the European trial summary.
How sulthiame is being positioned as a sleep apnea drug
Obstructive sleep apnea occurs when the upper airway repeatedly collapses during sleep, temporarily stopping breathing, lowering oxygen levels, and disrupting rest. For many years, CPAP—continuous positive airway pressure—has been the standard and most effective method to keep the upper airway open through the night, but many patients find the mask uncomfortable or difficult to use.
Sulthiame is an anticonvulsant first synthesized in the 1950s and sold in several European nations as well as Israel, Japan, and Australia to treat partial seizures; it has not been registered in the United States. Trial reporting described sulthiame’s potential mechanism as stabilizing the body’s control of breathing and increasing respiratory drive, lowering the likelihood of airway collapse. A preliminary European study referenced in the reporting also suggested sulthiame could improve upper airway muscle tone and stabilize respiratory control.
Quick context: where this fits in the treatment landscape
At the end of 2024, the US Food and Drug Administration approved tirzepatide (brand names Mounjaro or Zepbound) for adults with obesity and moderate-to-severe sleep apnea, the first medicine approved for the airway condition; its sleep-related benefits were described as primarily stemming from weight loss in the neck that enlarges the airway. Researchers behind sulthiame argue there remains “a clear, unmet need for an effective and well-tolerated treatment” that acts more directly on underlying contributors like airway muscle function and respiratory control.
What’s next
The research team is now pointing toward larger and longer studies to test whether benefits persist over time and to clarify safety across broader patient groups. For patients and clinicians watching the space, the immediate question is whether this sleep apnea drug approach can move from a promising European trial result into sustained, widely tolerated treatment—especially for those who struggle with mask-based therapy.
