A European epilepsy drug, sulthiame, has shown potential in alleviating symptoms of obstructive sleep apnea (OSA), according to a recent clinical trial. The findings, presented at the European Respiratory Society (ERS) Congress 2024 in Vienna, indicate that sulthiame reduces breathing pauses during sleep and improves blood oxygen levels in patients with OSA.
The double-blind, randomized, placebo-controlled trial, led by Dr. Jan Hedner from Sahlgrenska University Hospital and the University of Gothenburg in Sweden, involved 298 patients with OSA across multiple centers in Europe. These patients had reported intolerance or refusal to use continuous positive airway pressure (CPAP) machines or mouthpieces, the standard treatments for OSA.
Impact on Apnea-Hypopnea Index
The study participants were divided into four groups: three receiving different doses of sulthiame (100 mg, 200 mg, and 300 mg daily) and one receiving a placebo. The results showed a dose-dependent reduction in the apnea-hypopnea index (AHI), a measure of respiratory pauses during sleep. Specifically, AHI decreased by 17.8% in the low-dose group, 34.8% in the medium-dose group, and 39.9% in the high-dose group. When using a more stringent AHI measure, the reduction in respiratory pauses was nearly 50% in the highest dosage group compared to placebo.
Patient-Reported Outcomes and Side Effects
In addition to improved breathing patterns, patients taking sulthiame reported feeling less sleepy during the daytime. However, some participants experienced mild to moderate side effects, including paresthesia (pins and needles), headache, fatigue, and nausea.
Mechanism of Action
Sulthiame, marketed as Ospolot in Europe, acts as a carbonic anhydrase inhibitor, which stimulates upper airway muscles. This mechanism helps to keep the airways open during sleep, addressing a key issue in OSA.
Expert Commentary
Dr. Sophia Schiza, Head of the ERS assembly on sleep-disordered breathing and professor of respiratory and sleep medicine at the University of Crete, Greece, who was not involved in the study, noted the promising nature of the results. She emphasized the need for further research to evaluate the long-term effects and potential side effects of sulthiame, including its impact on reducing blood pressure and preventing cardiovascular disease in people with OSA.
Future Directions
While sulthiame is currently approved for treating epilepsy in Europe, it is not approved for use in the United States. Dr. Hedner emphasized the need for a phase III study to confirm the respiratory benefits of sulthiame in a larger group of OSA patients before it can be widely adopted as a treatment. Further research will also focus on understanding the underlying mechanisms of OSA to facilitate more personalized treatment approaches.
