A drug used in Europe to treat epilepsy may help people with obstructive sleep apnea breathe more easily during sleep, according to a new clinical trial.

Researchers found that the medication sulthiame reduced breathing interruptions and improved oxygen levels overnight in people with moderate to severe sleep apnea.

The findings were published recently in the journal The Lancet.

The study included 298 adults with sleep apnea from four European countries. One-quarter of them received a placebo, while the rest were given different doses of sulthiame.

Neither the participants nor the researchers knew who received the real drug.

People who received higher doses of sulthiame had up to 47% fewer breathing interruptions during sleep compared with those taking a placebo. They also showed better oxygen levels overnight, researchers reported.

The drug appears to help by improving the body’s control of breathing. This may reduce the odds of the airway collapsing during sleep, which is the main cause of obstructive sleep apnea.

Most side effects reported in the study were mild and temporary.

Lead researcher Jan Hedner, a senior professor of pulmonary medicine at the University of Gothenburg in Sweden, said the findings could open the door to new treatment options.

"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 said. 

"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," Hedner added.

Obstructive sleep apnea occurs when the upper airway repeatedly collapses during sleep, causing pauses in breathing and drops in oxygen levels. 

These interruptions can disturb sleep throughout the night.

Over time, untreated sleep apnea increases the risk of serious health problems such as high blood pressure, heart disease, stroke and type 2 diabetes.

The most common treatment today is continuous positive airway pressure (CPAP). This device uses a mask to keep the airway open during sleep.

Although CPAP works well, many patients struggle to use it.

Studies show that up to half of patients stop using CPAP within a year, often because the mask feels uncomfortable or disrupts sleep.

Sulthiame has already been approved in some countries as a treatment for childhood epilepsy. Researchers are now studying whether it could also become the first medication that directly treats sleep apnea.

The drug is considered an investigational drug in the U.S. and Canada.