Leaving Them Breathless

Researchers at McGill University, Montreal, Canada, found that the inhalation of vaporized cannabis had no effect on the symptoms of chronic pulmonary obstructive disease (COPD), an umbrella term used to describe a variety of progressive lung diseases that cause breathing difficulties.

Smoking cannabis has obvious drawbacks for those with lung complaints, especially when mixed with tobacco. However, past studies have suggested that cannabis may help to open airways in asthmatics, and some COPD sufferers have reported reduced breathlessness with the use of medical cannabis.

The Canadian team set out to find out if cannabis vapor would have an impact on symptoms in a randomized, controlled crossover trial with 16 patients with severe COPD (1). Half of the patients were given vaporized cannabis and half a placebo, before using a stationary bike. The experiment was then repeated with the cannabis and placebo groups switched. The results revealed no significant effect of cannabis on exercise performance or breathlessness across the group.

So is this the end for cannabis as a treatment for COPD? Not quite. Despite the discouraging results of their initial study, the researchers point out that the number of patients was small and each received only a single dose. They believe further research is warranted, looking at a larger group of patients, including those with less advanced disease, and trialing several different cannabis formulations.

Reference
SJ Abdallah et al. “Effect of vaporized cannabis on exertional breathlessness and exercise endurance in advanced COPD: a randomized controlled trial”, Ann Am Thorac Soc, (Epub ahead of print) (2018). DOI: 10.1513/AnnalsATS.201803-198OC