THE LEGALISATION of cannabis for medical use has induced heated debate both in the political and medical spheres. Recent news of a young epileptic patient receiving cannabis oil has dominated the headlines in the UK, alongside the legalisation of the therapeutic. However, the discussion regarding the beneficial effects of cannabis is not a new phenomenon. In the 1970s it was widely reported that smoking cannabis dilated the airways of asthmatic and non-asthmatic patients and, with these >40-year-old reports in mind, a research team from McGill University, Montreal, Canada, investigated the effects of inhaled vaporised cannabis on the exercise performance of chronic obstructive pulmonary disease (COPD) patients.
Sixteen patients, all receiving the optimal dual or triple inhalation therapy for their advanced COPD, were randomly selected to receive either a single dose of vaporised cannabis or placebo before completing an exercise routine on a stationary bike. The patients were swapped from the trial to the treatment group, ensuring that neither the patients nor the researchers knew when the cannabis or the placebo was administered.
While the researchers noted that there was no overall statistically significant beneficial effect on breathlessness after receiving cannabis, a negative effect of cannabis on mood or cognitive function was not reported. Additionally, varied responses of the patients to vaporised cannabis were highlighted. Of the 16 patients, 4 presented with improved breathing following the administration of cannabis, while for the remaining 12 patients, breathlessness stayed the same or worsened following the inhalation of cannabis. Therefore, the team noted that inhaled vaporised cannabis does not significantly worsen or improve COPD patient activity-related breathlessness.
Although the trial was limited by the small number of participants, senior study author Dr Denis Jessen, McGill University, called for further investigations into the effects of vaporised cannabis on COPD patients, for whom breathlessness has a high burden. “Future clinical trials are warranted and should evaluate the therapeutic potential of various doses of vaporised and oral cannabis, including oils and pills, administered over longer periods of time in patients with mild-to-moderate COPD,” he concluded.
