The standard treatment for obstructive sleep apnoea is sleeping with a plastic mask strapped on your face.

Patients with obstructive sleep apnoea have air blown through the mask to keep the airways open with a “continuous positive airway pressure” (CPAP) machine.

This treatment is safe and effective. It reduces sleepiness, improves mood and quality of life.

Overall, it counters OSA’s frightening and disruptive symptoms. This includes loud snoring and breathing that stops and starts.

OSA’s overall impact includes tiredness, and an increased risk of high blood pressure, stroke, heart disease and type 2 diabetes.

CPAP saves you from all that.

Here’s the problem. While CPAP is effective, “it’s relatively poorly tolerated, with approximately 50 per cent of patients unable or unwilling to use the treatment in the long term”.

One in 20 Australians have some degree of OSA.

A promising alternative?

In a clinical trial from Sweden, patients with OSA experienced a significant reduction in their symptoms after taking an epilepsy drug called “sulthiame”.

Sulthiame is a drug “that targets the respiratory system”.

By inhibiting an enzyme called “carbonic anhydrase”, the drug stimulates the upper airway muscles”.

How might this help?

People with narrow throats are more likely to have sleep apnoea and snore during sleep as their throat muscles relax.

Participants who took sulthiame “had fewer pauses in their breathing and higher levels of oxygen in their blood during sleep”.

The results of the trial were presented at the European Respiratory Society Congress in Vienna.

What happened in the study

The trial was a double-blind, randomised, placebo-controlled trial – the “gold standard” in medical research.

There were 298 participants with OSA, spread across 28 treatment centres in Spain, France, Belgium, Germany and the Czech Republic.

All participants were unable to tolerate or refused to use CPAP machines. They also refused mouthpieces designed to keep the airways open.

The patients were assessed with polysomnography at the start of the trial, and after four weeks and 12 weeks in the study.

Polysomnography is a diagnostic tool in sleep studies. It records your brain waves, the oxygen level in your blood, and your heart rate and breathing during sleep.

It also measures eye and leg movements.

The patients were divided into four groups:

• 74 people took 100 milligrams of sulthiame daily
• 74 took 200 milligrams
• 75 took 300 milligrams
• The remaining 75 took a placebo (dummy pill).

Obstructive sleep apnoea can range from mild to severe.

Severity is measured using a rating system called the apnoea-hypopnea index (AHI). The AHI measures an average number of apnoea and hypopnoea episodes you have per hour that you sleep.

Apnoea is when you stop breathing while asleep or have almost no airflow.

Hypopnea is 10 seconds or more of shallow breathing in which a person’s airflow drops by at least 30 per cent.

In the study, an AHI measure counted the frequency of respiratory pauses during sleep.

These were:

• 17.8 per cent lower for patients taking the lowest dose
• 34.8 per cent lower for patients on the medium dose
• 39.9 per cent lower for patients on the highest dose.

Using a different AHI measure, the effect of the treatment was close to “a 50 per cent reduction of respiratory pauses with more profound lowering of oxygen levels”.

OSA patients who had felt sleepy during the daytime also felt less so when they took sulthiame.

Side effects experienced by the people taking sulthiame, such as pins and needles, headache, fatigue and nausea, were generally mild or moderate.

What the researcher says

The research was presented by Professor Jan Hedner from Sahlgrenska University Hospital and the University of Gothenburg in Sweden.

“People taking sulthiame in the trial had a reduction in OSA symptoms, such as stopping breathing during the night and feeling sleepy during the day,” he said in a statement from the ERS.

“Their average levels of oxygen in the blood were also improved with the treatment.”

He said this suggested “that sulthiame could be an effective treatment for OSA, especially for those who find they cannot use the existing mechanical treatments”.

A phase three study is required “to confirm the beneficial respiratory effects of this drug in a larger group of patients with OSA”.