A new epilepsy drug was tested to help treat sleep apnea. How effective was it?

The next phase of the trials is expected to include more than 400 subjects.
Mert Erdemir
Obstruction Sleep Apnea.decade3d/iStock

Sleep apnea is a widespread problem that affects many people regardless of age. Besides reducing sleep quality, it can cause you to snore loudly, and this would disturb not only you but also the people around you.

There are two types of sleep apnea: obstructive and central. Obstructive sleep apnea is the most common type, which causes you to stop breathing during sleep. It leads your muscles to relax and the soft tissue to block the airway, which results in short pauses in breathing.

The most recommended solution for the disorder is to use a CPAP (continuous positive airway pressure) machine that steadily applies a stream of air to keep your airway open during the night and enable you to breathe. Unfortunately, wearing a mask throughout the night is not the most comfortable option. Other than that, the alternatives are mouthguards and a variety of surgical options.

But now, researchers have discovered a new potential treatment that can eliminate the mechanical treatments such as CPAP machines and mouthguards. An early clinical trial conducted by a team of researchers has shown that sulthiame, a drug used to treat epilepsy, eases sleep apnea. The results of the trial were published in the American Journal of Respiratory and Critical Care Medicine.

How effective is it?

The trial included 60 people struggling with moderate or severe sleep apnea. The subjects were divided into three groups according to the doses they were given: high, low, and placebo. The results demonstrated that the drug reinforced the oxygenation of the blood and reduced the breathing pauses by inhibiting an enzyme that serves to maintain the balance of carbon dioxide in the body.

"For just over a third of patients in the study, only half of their breathing pauses were left, and in 1 in 5, the number fell by at least 60%," said lead researcher Dr. Jan Hedner, a professor of pulmonary medicine at the University of Gothenburg in Sweden.

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Though the drug proved to be relatively safe, some subjects quit the trial due to reported side effects such as headaches, a pins and needles sensation on the skin, and shortness of breath. In addition to that, the current results promise only "a partial solution" since some patients hardly responded to the drug while others did well. 

"I don't see that this would necessarily be a full solution or complete substitute for a therapy like CPAP (continuous positive airway pressure)," Dr. Jonathan Jun, a sleep medicine expert at Johns Hopkins Hospital in Baltimore, told U.S. News. 

Now, the research team expanded the trials to 400 subjects for the next phase, which is expected to be finalized by the end of the year or early next year.

So far, the effectiveness of the drug has not been proven, and trials are going on, but the study is still promising since it may lead scientists to come up with new combination therapies.


Rationale: Current therapies in obstructive sleep apnea (OSA) are limited by insufficient efficacy, compliance, or tolerability. An effective pharmacological treatment in OSA is warranted. Carbonic anhydrase (CA) inhibition has been shown to ameliorate OSA. Objective: To explore the safety and tolerability of the CA inhibitor sulthiame (STM) in OSA. Methods: A four-week, double-blind, randomized, placebo-controlled dose guiding trial in patients with moderate/severe OSA not tolerating positive airway pressure treatment. Measurements and results: Intermittent paresthesia was reported by 79, 67, and 18% of patients receiving 400 mg STM (N=34), 200 mg STM (N=12), or placebo (N=22), respectively. Dyspnea was reported only after 400 mg STM (18%). Six patients in the higher dose group withdrew due to an adverse event. There were no serious adverse events. STM reduced the apnea-hypopnea index (AHI) from 55.3 to 33.1 events/h (41.0%) in the 400 mg group and from 61.2 to 40.7 events/h (32.1%) after 200 mg (p<0.001, respectively). Corresponding placebo values were 53.9 and 50.9 events/h (5.4 %). The AHI reduction threshold of ≥50% was reached at 40% after 400 mg, 25% after 200 mg, and 5% following placebo. Mean overnight oxygen saturation improved by 1.1% after 400 mg and 200 mg (p<0.001 and p=0.034, respectively). Patient-related outcomes were unchanged. Conclusions: STM showed a satisfactory safety profile in moderate/severe OSA. STM reduced OSA by more than 20 events/h, one of the strongest reductions reported in a drug trial in OSA. Larger scale clinical studies of STM in OSA are justified. Clinical trial registration is available at https://www.clinicaltrialsregister.eu/https://www.clinicaltrialsregister.eu/, ID: 2017-004767-13. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

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