First effective drug for sleep disorder identified

In a clinical trial conducted at the University of Illinois at Chicago, researchers have demonstrated the first promising drug treatment for a common and life-threatening sleep disorder called sleep apnea.

The drug, an antidepressant called mirtazapine, significantly reduced the symptoms of sleep apnea. It cut in half the number of times breathing stopped or slowed during sleep and reduced the number of times sleep was disrupted by 28 percent. All 12 patients who participated in the study showed improvement.

“The drug provided the largest benefit and the most consistent improvement of any pharmaceutical therapy tested in controlled studies to date,” said David Carley, professor of medicine, pharmacology and bioengineering and director of research at the UIC Center for Sleep and Ventilatory Disorders.

The results of the trial will be presented this week at the annual meeting of the Associated Professional Sleep Societies in Chicago by Carley and co-investigator Dr. Miodrag Radulovacki, professor of pharmacology and medicine at UIC.

“This has real clinical significance,” said Radulovacki. “An estimated 15-20 million people in the United States suffer from sleep apnea, yet there is currently no cure and no fully effective long-term treatment for the disorder.”

Apnea — which means “without breath” — is diagnosed when a person periodically stops breathing for 10 seconds or more or has episodes of reduced breathing during sleep. People suffering from sleep apnea may stop breathing hundreds of times a night, often for a minute or longer. The disorder is associated with increased risk of high blood pressure, heart attack, stroke and adult-onset diabetes. Behavioral problems and cognitive impairments can occur due to insufficient rest.

At present, sleep apnea is treated with mechanical devices, most often masks or nasal prongs, that maintain a continuous positive airway pressure. Such devices are uncomfortable, however, and difficult to use long-term.

The 12 patients in the UIC study were between the ages of 20 and 70. They received one of two dosages of mirtazapine or a placebo an hour before bedtime. They were monitored throughout the night in the UIC Center for Sleep and Ventilatory Disorders after each of three seven-day treatment periods.

The clinical trial at UIC followed years of laboratory tests of several classes of medications on a strain of rats that exhibit sleep apneas similar to the human disorder. Mirtazapine showed the most promise; other drugs either improved the condition only marginally or made it worse.

Mirtazapine blocks the activity of a chemical in the nervous system called serotonin that is involved in regulating mood, emotion, appetite and sleep.

The UIC study was funded by NV Organon, which markets mirtazapine as Remeron for the treatment of depression.

Mirtazapine has not been approved by the U.S. Food and Drug Administration for the treatment of sleep apnea. Its use in this trial was approved by a UIC institutional review board for experimental purposes only.