Scientists hope THC might one day treat sleep apnea

CPAP masks prevent the airway from collapsing during sleep, but must be worn every night.

Sleep scientists at the University of Illinois at Chicago have spent years studying dronabinol – an FDA-approved pill containing tetrahydrocannabinol (THC) – as a potential treatment for sleep apnea.

Earlier this year, they showed that it could significantly reduce the occurrence of apneas, or pauses in breathing, in a small group of patients – and without causing other sleep disruptions.

Research associate Michael Calik, PhD explains that the challenge has been finding a drug that can treat sleep apnea without creating new problems.

“Sleep apnea research has been going on for 30+ years. The main reason why we’ve always reached obstacles regarding finding a drug form to treat sleep apnea has been: when you try to treat sleep apnea, usually you will have other effects on sleep quality.”

However, scientists are keen on finding a treatment regimen that will be easier to follow than the current ‘gold standard’: a CPAP mask. Currently, there is no treatment for sleep apnea in drug form.

“Adherence to CPAP is bad. To pop a pill just before bed, the adherence would be a lot better and it could be a lot easier for people to stick on it. That’s the goal.”

Recently, Dr. Calik co-authored a study that identified how dronabinol works to reduce apneas during sleep, through its action on cannabinoid receptors in the peripheral nervous system. The findings were published this month in the journal Respiratory Physiology & Neurobiology.

“What we found was a minimum of 100 μg injections per nodose ganglia were able to totally attenuate or abolish apnea within rats.”

Dr. Calik says the findings add “proof that what we saw a couple years ago with systemic injections of dronabinol was happening extensively at the peripheral nervous system.”

Sleep apnea is thought to be caused by a loss of muscle tone in the upper airway during sleep, explains Dr. Calik. THC, on the other hand, seems to increase this tone.

While the only study in humans was a proof of concept trial, he notes that dronabinol has already been approved to treat other conditions.

“Dronabinol has been on the market for already two decades, if not more. It’s used to treat vomiting and nausea in cancer patients undergoing chemotherapy.”

Dr. Calik says the next step is to hopefully extend the results through a larger study and to figure out more precisely how cannabinoid mechanisms interact with the peripheral and central nervous systems when it comes to sleep apnea.