Low dose opioids are often recommended in clinical practice guidelines for the relief of refractory breathlessness in advanced COPD but physicians remain reluctant to prescribe them, an international expert says.

Speaking during a TSANZ themed symposia on new horizons in clinical and therapeutic management of COPD Dr Jean Bourbeau, Director of the Respiratory Epidemiology and Clinical Research Unit at the Montreal Chest Institute at the McGill University referred to a South Australian study by palliative care expert David Currow and colleagues that showed clinicians prescribed opioids for pain but not for breathlessness.

This was despite evidence showing single dose oral morphine relieved exertional breathlessness and improved exercise tolerance in symptomatic COPD patients, most likely through a central mechanism of action.

The most frequently reported barriers toward prescription of opioids were resistance of the patient, fear of possible adverse effects, and fear of respiratory depression.

“Although additional research is necessary the majority of available evidence does suggest that systemic low to moderate dose opioids are safe and effective for the relief of chronic refractory breathlessness in selected patients with advanced COPD,” Professor Borbeau  concluded.

But, he said, a potential role for cannabis in the medical management of COPD was less certain. The acute effects of cannabis in healthy and asthmatic individuals included bronchodilation but current and cumulative use was linked to cough, sputum production independent of tobacco smoking. 

The Canadian led CAN BREATHE in COPD trial was currently investigating the efficacy and physiological mechanism of action of inhaled vaporized cannabis for the relief of physical activity-related breathlessness and exercise endurance in symptomatic patients with severe-to-very severe COPD.

The study is due to report its results at the end of this month but early results suggested cannabis had no acute effect on breathlessness and exercise tolerance, with most patients reporting side effects.