The drug is called dronabinol, and it is based on a synthetic version of Delta-9 tetrahydrocannabinol (THC) — the main psychoactive compound responsible for the "high" in cannabis use.
The randomized clinical trial is the longest and largest of its kind, and the results are from its second phase. Dronabinol is already in use for the treatment of nausea and vomiting in patients undergoing chemotherapy.
David W. Carley, a professor of biobehavioral health sciences at the University of Illinois at Chicago (UIC), jointly led the study with Dr. Phyllis Zee, professor of neurology at Northwestern University Feinberg School of Medicine and director of the Northwestern Medicine Sleep Disorders Center, both in Chicago, IL.
At least a mild form of sleep apnea is thought to affect 1 in 5 Americans, and treatment options are limited. Obstructive sleep apnea — the most prevalent form of the condition — is usually treated mechanically with a continuous positive airway pressure (CPAP) device. However, treatment adherence to this mechanical option is very poor.
Recurrent, untreated sleep apnea may lead to cardiovascular problems, such as heart disease and stroke. "There is a tremendous need for effective, new treatments [for] obstructive sleep apnea," says Prof. Carley, who is also the first author of the paper.
The drug tested in this trial — results of which are published in journal Sleep — works by targeting the brain. Dr. Zee explains, "The CPAP device targets the physical problem but not the cause."
"The drug targets the brain and nerves that regulate the upper airway muscles. It alters the neurotransmitters from the brain that communicate with the muscles."
"When people take a pill to treat apnea, they are treated for the entire night," adds Prof. Carley.
Those who took the highest dose, i.e., 10 milligrams of dronabinol, reported the highest satisfaction with the treatment. They showed decreased signs of subjective sleepiness and a lower incidence of apnea and hypopnea episodes.
Compared with full adherence to the mechanical CPAP device — which is rare — the new drug reduced apnea symptoms by 33 percent.