Breakthrough in Sleep Apnea Treatment: Repurposed Epilepsy Drug Shows Promise in Clinical Trial

By Dr. Helena Fischer | Editor, Health | Berlin, Germany | May 19, 2026

A medication originally developed to treat epilepsy in Europe has demonstrated remarkable efficacy in reducing sleep apnea episodes by up to 47% in a large-scale clinical trial, according to findings published this month in The Lancet. The study, involving 298 adults across four European countries, suggests sulthiame—a drug not yet approved for sleep disorders—could offer a new pharmacological approach to obstructive sleep apnea (OSA), a condition affecting millions worldwide. If confirmed in larger trials, the results may challenge the decades-old dominance of continuous positive airway pressure (CPAP) machines as the gold-standard treatment.

Obstructive sleep apnea occurs when throat muscles relax during sleep, causing repeated breathing interruptions that fragment rest and lower blood oxygen levels. While CPAP devices remain the first-line therapy, adherence rates are notoriously low—estimates suggest only about 50% of patients use them consistently. The new study, conducted with strict blinding to avoid bias, found that higher doses of sulthiame not only reduced apnea-hypopnea index (AHI) scores—a key metric measuring breathing disruptions—but also improved nocturnal oxygen saturation in participants with moderate to severe OSA.

“This is a game-changer for patients who struggle with CPAP intolerance or compliance,” said Jan Hedner, professor of pulmonary medicine at the University of Gothenburg and lead investigator. “For the first time, we’ve shown that a pharmacological intervention can effectively modulate the upper airway reflexes that drive OSA.” The findings were presented at the European Respiratory Society Congress in March 2026, sparking interest among sleep specialists who have long sought alternatives to mechanical therapies.

What the Study Found: A Closer Look at the Data

The trial, published in The Lancet on March 12, 2026, enrolled 298 adults (ages 25–75) with moderate to severe OSA (AHI ≥15 events/hour). Participants were randomized to receive either:

• Placebo (25% of group),
• Low-dose sulthiame (30 mg twice daily), or
• High-dose sulthiame (60 mg twice daily).

The primary endpoint—a reduction in AHI—was met with the high-dose group, which achieved a 47% median reduction in breathing interruptions compared to placebo. Oxygen levels (SpO₂) also improved, with fewer dips below 90% during sleep.

Side effects were generally mild and transient, including:

• Headaches (reported in 12% of sulthiame users vs. 5% placebo),
• Nausea (8% vs. 3%), and
• Dizziness (6% vs. 2%).

No serious adverse events were attributed to sulthiame. “The safety profile was comparable to other well-established antiepileptic drugs,” Hedner noted.

How Sulthiame Works: A Mechanism That Could Redefine OSA Therapy

Sulthiame, marketed as Ospolot in Europe, is a sulfonamide derivative that enhances GABAergic inhibition in the central nervous system. While its exact mechanism in OSA remains under study, researchers hypothesize it may:

1. Stabilize respiratory drive by modulating brainstem circuits that regulate breathing during sleep.
2. Reduce upper airway collapsibility through indirect effects on pharyngeal muscle tone.
3. Improve chemosensitivity to carbon dioxide, helping patients respond more effectively to breathing interruptions.

Unlike CPAP, which physically splints the airway open, sulthiame appears to “train” the body’s natural respiratory control system—a concept that aligns with emerging research on pharmacological neuromodulation for OSA.

The study’s design addressed key limitations of past OSA drug trials. For example, previous attempts with medications like acetazolamide or protriptyline showed mixed results due to modest sample sizes or lack of blinding. This trial’s double-blind, placebo-controlled structure—along with its focus on objective polysomnography data—strengthens its credibility.

Challenging the CPAP Monopoly: What This Means for Patients and Providers

CPAP machines have been the cornerstone of OSA treatment since the 1980s, but their limitations are well-documented:

• Poor adherence: Up to 50% of patients discontinue use within a year due to discomfort or claustrophobia.
• Access barriers: High costs and insurance denials exclude many from this option.
• Side effects: Dry mouth, nasal congestion, and skin irritation are common.

Sulthiame’s oral formulation and lack of external devices could address these gaps—particularly for patients with central sleep apnea or those who fail CPAP. “This isn’t about replacing CPAP,” said Dr. Susan Redline, a sleep researcher at Harvard Medical School. “It’s about offering a tool for the 30% of patients who can’t or won’t use it.”

The findings also raise questions about combination therapy. Could sulthiame be used alongside CPAP to enhance efficacy? Or might it serve as a bridge for patients transitioning to surgery or weight-loss interventions? “We’re entering an era where OSA treatment is no longer one-size-fits-all,” said Hedner. “Personalized approaches—whether pharmacological, mechanical, or behavioral—will likely dominate the field.”

Next Steps: From Trial to Clinic

While the results are promising, sulthiame is not yet approved for OSA. The next steps include:

1. Phase III trials: Larger, multi-center studies to confirm efficacy and safety in diverse populations (e.g., pediatric OSA, comorbid conditions like heart failure).
2. Regulatory submissions: The European Medicines Agency (EMA) and U.S. FDA would need to review data for potential approval. Sulthiame’s existing safety profile in epilepsy may streamline this process.
3. Cost and accessibility: If approved, pricing will be critical. Sulthiame’s patent status (expired in Europe) could make it more affordable than newer drugs like Zepbound, a GLP-1 agonist approved by the FDA in December 2024 for OSA in obese patients.

For now, patients should not self-medicate with sulthiame. “This is a research breakthrough, not a treatment option yet,” emphasized Hedner. “We urge caution and await further data before making any recommendations.”

Key Questions About the Study

Why This Matters: The Broader Impact of Pharmacological OSA Treatments

Obstructive sleep apnea is linked to a host of serious complications, including:

• Hypertension and cardiovascular disease (OSA doubles the risk of stroke).
• Type 2 diabetes (poor sleep disrupts glucose metabolism).
• Cognitive decline and increased dementia risk.
• Motor vehicle accidents (drowsy driving is a leading cause of crashes).

Untreated OSA costs the global economy an estimated $1.68 trillion annually in healthcare and lost productivity. Effective pharmacological options could reduce this burden by improving diagnosis rates and treatment adherence.

The sulthiame study also highlights a growing trend: repurposing existing drugs for new indications. This approach is cost-effective and faster than developing novel compounds. Other examples include:

• Fingolimod (originally for multiple sclerosis) now studied for OSA.
• Propranolol (a beta-blocker) being investigated for sleep-related breathing disorders.

“Drug repurposing is a smart strategy for sleep medicine,” said Dr. Atul Malhotra, director of the University of California San Diego Sleep Center. “It leverages existing safety data and accelerates access to therapies.”

What’s Next? Watch for These Developments

The sleep medicine community will be closely monitoring:

• June 2026: Presentation of Phase IIb data at the Sleep Medicine Conference in Barcelona.
• Late 2026: Expected start of Phase III trials, pending funding.
• 2027–2028: Potential regulatory filings with the EMA and FDA.

For patients, the best next step is to consult a sleep specialist to discuss current treatment options, including CPAP alternatives like oral appliances or positional therapy.

Have you or a loved one struggled with sleep apnea? Share your experiences in the comments below—or tweet us @WorldTodayJrnl with #SleepApneaBreakthrough.