The synthetic, pill version of Delta-9 THC showed a reduction in AHI of more than 10 events per hour with both 2.5 mg and 10 mg doses.
Phyllis Zee, MD, PhD
Conducted by the University of Illinois at Chicago and Northwestern Medicine, the study examined 73 adults with moderate to severe obstructive sleep apnea, revealing that the synthetic version of Delta-9 tetrahydrocannabinol (THC) was associated with a lower overall apnea/hypopnea index (AHI) compared with placebo.
Participants were randomized to either 2.5 mg dronabinol (n = 21), 10 mg dronabinol (n = 27), placebo (n = 25) once daily pills, an hour before sleep for 6 weeks. At baseline, AHI was measured (25.9 ±11.3) as well as Epworth Sleepiness Scale (ESS) scores (11.45 ±3.8) and the mean latency of maintenance of wakefulness (MWT) test (19.2 ±11.8 minutes)
After the 6 week period, the 10-mg group expressed having the highest overall satisfaction (P =0.4), experiencing an AHI reduction of 12.9 ±4.3 events per hour (P =.003). The 2.5-mg group experienced a reduction in AHI of 10.7 ±4.4 events per hour (P =.04) compared to placebo. MWT sleep latencies were unchanged from baseline in all groups.
Dronabinol in the 10-mg dose also reduced ESS score by 3.8 ±0.8 points from baseline (P <.0001) and 2.3 ±1.2 points compared to placebo (P =.05).
"Dronabinol is a medication, whereas the current therapies available involve either mechanical approaches to open the airway, or surgical approaches of the upper airway, including a nerve stimulation device," Phyllis Zee, MD, PhD, the Benjamin and Virginia T. Boshes professor of neurology at Northwestern University Feinberg School of Medicine and director of the Northwestern Medicine Sleep Disorders Center, said. "It clearly will provide more choices for providers, and open up the door for the development of other drug-based therapies that can be tailored to individual patient characteristics and needs."
The treatment is notably different from the currently available interventions for OSA, the most common of which are continuous positive airway pressure (CPAP) devices, which act as a splint to prevent airway collapse.
David Carely, PhD
The biggest issue with CPAP devices is that they struggle when it comes to treatment adherence. Co-lead author David C. Carley, PhD, the Katherine M. Minnich endowed professor of narcolepsy, sleep, and health research at the University of Illinois at Chicago’s College of Nursing, said in a statement that on average, patients only use the devices for an estimated 4 hours a night, if at all.
"So the best they can get is a roughly 50 percent improvement in their apnea. When people take a pill to treat apnea, they are treated for the entire night,” he said.
Dronabinol did not face this adherence issue - during the trial, treatment adherence was consistent among all groups (0.3 ±0.6 missed doses/week). Compared to even complete compliance with mechanical treatment with CPAP, the severity of OSA was reduced by 33% with dronabinol.
"The CPAP device targets the physical problem but not the cause," Zee said. "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. [A] better understanding of this will help us develop more effective and personalized treatments for sleep apnea."
Carley said there is a "tremendous" need for more treatment options for OSA. He noted that researchers have attempted to find a treatment for OSA without success for almost 35 years. Zee stated "pharmacotherapy has the potential to expand treatment options," as these other options become uneffective for more and more patients.
"The next step is to test the effectiveness and safety in larger multicenter studies," Zee said. "Our early results indicate the potential for pharmacotherapy as a treatment for OSA. However, larger scale studies are needed assess the generalizability of these findings to the treatment of OSA."
Dronabinol is currently approved by the US Food and Drug Administration for the treatment of nausea and vomiting for patients undergoing chemotherapy.
The study is available in the journal SLEEP. Previous study of dronabinol for sleep apnea in animal models was published there in 2002.