COPD Drugs Not as Effective in Patients Who Smoke or have Viral Infection, Study Finds
A collaborative research study between several Australian institutions suggests that cigarette smoking and infection with viruses such as influenza can reduce the effectiveness of symptom-reliever drugs like salbutamol in patients with chronic obstructive pulmonary disease (COPD).
These findings were published in a research article, “Influenza A virus infection and cigarette smoke impair bronchodilator responsiveness to β-adrenoceptor agonists in mouse lung,” in the Clinical Science journal.
COPD, a term used to describe several types of lung diseases such as chronic bronchitis, emphysema, and chronic obstructive airways disease, is distinguished by inflamed and blocked airways that make breathing difficult. The recurrent inflammation of the lungs leads to permanent structural changes, making COPD patients more susceptible to frequent infections. Smoking tobacco is the primary risk factor for COPD, which works by altering the immunity of the patients and raising their vulnerability to infections.
There is currently no cure for COPD, but the symptoms can be relieved in various ways, including through medicines. Among them, β2-adrenoceptor agonists such as salbutamol are frequently used to expand the patient’s airways and allow them to breathe easily. But it has been suggested that smoking may influence the effectiveness of the drugs.
To clarify the mechanism involved in the loss of drug effectiveness, researchers examined sections of lung exposed to cigarette smoke, as well as to influenza A virus. The team discovered that lung tissues exposed to cigarette smoke and viral infection responded less to salbutamol than the unexposed tissues.
“By understanding the mechanisms responsible for reduced sensitivity to current bronchodilators, we can then design alternative, more efficacious agents to help treat people with COPD, especially during a viral exacerbation,” the study’s lead author, Dr. Chantal Donovan from Monash University in Victoria, Australia, said in a press release.
“There is a clear need for new therapies that can overcome the limitations of current drugs used to treat COPD and associated flare-ups. When combined with knowledge gained through clinical research, animal models utilizing cigarette smoke exposure are a valuable tool in the quest to identify new therapies for this life-changing condition,” said senior study author Dr. Ross Vlahos, associate professor at RMIT University in Melbourne, Australia.
The researchers are currently preparing a commentary article to accompany the research paper, which will soon be published in the journal Clinical Science.
“The findings of this study suggest that cigarette smoke and respiratory virus infections may impair the ability of salbutamol to effectively bronchodilate the airways. These findings emphasize yet again that smoking is bad for you, and especially so if you have asthma or COPD,” said Prof. Sebastian Johnston from Imperial College London in England, one of the authors of the upcoming article. “It would be interesting to determine whether the other commonly used reliever bronchodilator ipratropium bromide, which acts via a different mechanism, is similarly impaired by cigarette smoke and/or viral infection.”