Living with chronic obstructive pulmonary disease? A new class of medications might help you breathe a little easier

The Bottom Line

  • Chronic obstructive pulmonary disease (COPD) reduces the quality of life of many Canadian adults. 
  • A relatively new class of medications called phosphodiesterase 4 (PDE4) inhibitors can improve lung function and reduce the likelihood of flare-ups (aka bouts of coughing and breathlessness) by a small amount in people with COPD.
  • Side effects of using PDE4 inhibitors include: diarrhea, nausea, headache, vomiting, , and abdominal pain.  

If your life is particularly exciting, it may leave you breathless. Unfortunately, many who experience breathlessness on a regular basis suffer from chronic obstructive pulmonary disease, or COPD.

COPD – a lung disease that blocks air flow to the lungs – affects at least 4% of Canadians, and is a leading cause of illness and death nation-wide (1). In most cases, the symptoms of COPD start to appear after the age of 55, and the severity of the disease increases with age (2).

Symptoms of COPD can include shortness of breath, coughing, wheezing, and the production of mucus. Many people living with COPD find that these symptoms can interfere with basic daily activities; 45% percent of Canadians with COPD feel that they are in poor health, and 33% report that their health has declined within the last year (3).

Cigarette smokers or ex-smokers are most at risk for COPD, but not everyone who gets COPD has smoked cigarettes. Other risk factors include oversensitive airways, genetics, second-hand smoke, and workplace exposure to dust, organic materials, or air pollution (4).

COPD is a serious condition that unfortunately has no cure (4). However, there is a new treatment – phosphodiesterase 4 (PDE4) inhibitors – that may help people with COPD catch their breath (5).

What the research tells us

PDE4 inhibitors are a class of medications that open the airways and reduce lung inflammation. Two drugs, which come in tablet form and are taken orally, are currently available: roflumilast and cilomilast.

A systematic review found that adults with stable, moderate to very severe COPD who took PDE4 inhibitors experienced improved lung function and a lower likelihood of flare-ups, which are episodes of coughing and breathlessness. The improvements were small. These findings were based on tests that measured the maximum amount of air a person can forcefully exhale in one second. Additionally, the research showed that PDE4 inhibitors had little impact on improving COPD symptoms and quality of life. People who took PDE4 inhibitors did not report improved exercise tolerance.

PDE4 inhibitors were not without side effects. Common side effects included diarrhea, nausea, headache, vomiting, and abdominal pain. People taking roflumilast were particularly prone to weight loss, while high dose roflumilast was associated with an increased risk of negative psychiatric effects.

Although the results are promising, additional research needs to be done to determine the long-term positive and negative effects of PDE4 inhibitors, and whether these new medications can slow the progression of COPD. The authors of the review concluded that their findings lend cautious support for the use of these medications (5). If you have COPD, talk to your doctor about whether PDE4 inhibitors are a good option for you.

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Author Details


  1. Evans J, Chen Y, Camp PG, et al. Estimating the prevalence of COPD in Canada: Reported diagnosis versus measured airflow obstruction. [Internet] 2015. Statistics Canada, Canada. Available from 
  2. Government of Canada. Chronic obstructive pulmonary disease (COPD). [Internet] 2014. Government of Canada, Canada. Available from 
  3. Public Health Agency of Canada. Fast facts about Chronic Obstructive Pulmonary Disease (COPD) 2011. [Internet] 2011. Government of Canada, Canada. Available from 
  4. Han ML, Stoller JK, Hollingsworth H. Patient education: Chronic obstructive pulmonary disease (COPD), including emphysema (Beyond the Basics). [Internet] 2017. UpToDate, USA. Available from 
  5. Janjua S, Fortescue R, Poole P. Phosphodiesterase-4 inhibitors for chronic obstructive pulmonary disease. Cochrane Database Syst Rev. 2020; 5:CD002309. doi: 10.1002/14651858.CD002309.pub6.

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