A small study was recently done to prove Dronabinol safe, tolerable, and effective in treating obstructive sleep apnea. Researchers of the University of Illinois found that Dronabinol was able to lower the apnea hypopnea index (AHI) of participants by an average of 14 points.
Obstructive sleep apnea (OSA) is a sleep disorder in which one stops breathing (for seconds or minutes at a time) or experiences abnormally low breathing during sleep due to low muscle tone or obstructive tissue that blocks the airway. Hypopnea similarly is a sleep disorder but is characterized by abnormally shallow breathing during sleep. Additionally, the AHI is a tool used to categorize the severity of sleep apnea. The measurements are average apnea episodes per hour with a scale of 5-15/hr (mild), 16-30/hr (moderate), and above 30/hr (severe).
Participants age 21-65 with moderate or severe OSA were to self administer pills of 2.5, 5.0, or 10.0 mg of dronabinol nightly before sleep (at least 8 hour sleep) for 3 weeks. Doses were increased each step as tolerated (defined by no adverse events).
As per safety, the most common adverse event seen was somnolence (drowsiness and/or hypersomnia). This was seen in 29% of participants at 2.5 mg, 14% at 5 mg, and 50% at 10 mg. Overall, adverse events were seen in 67% of participants across all doses. All but two participants completed the study as these two were withdrawn due to severe adverse events.
Efficacy wise, dronabinol resulted in a reduction in AHI of participants by 14.1 ± 17.5 (P = 0.003) during the study. The effect in treating OSA was dose and position (supine vs. non-supine) independent. The effect was hypothesized to be due to dronabinol binding cannabinoid type 1 and 2 receptors to improve respiratory stability, block serotonergic activity, and prevent airway collapse.
Overall dronabinol seems safe and effective in treating obstructive sleep apnea and by extension hypopnea in humans. As this study was only a proof that the drug works, larger studies will need to be performed before dronabinol is available as a treatment for sleep apnea.
Bharati Prasad, Miodrag G. Radulovacki, David W. Carley. Proof of Concept Trial of Dronabinol in Obstructive Sleep Apnea. Frontiers in Psychiatry, 2013.