Sydney, April 11 (IANS): Smoking and viral infections can lower the effectiveness of drugs taken to treat chronic lung diseases, say Australian researchers.

Chronic Obstructive Pulmonary Disease (COPD) is the collective name for lung diseases including emphysema, chronic bronchitis and chronic obstructive airways disease. 

The findings showed that the effectiveness of a commonly used COPD symptom-reliever medication gets reduced owing to cigarette smoke exposure and influenza A infection in an animal model of the respiratory disease.

"There is a clear need for new therapies that can overcome the limitations of current drugs used to treat COPD and associated flare-ups," said senior study author Ross Vlahos from RMIT University in Melbourne, Australia.

Smoking is currently the main cause of COPD as it alters immunity and can increase a patient's susceptibility to infection which can worsen symptoms and cause flare-ups.

People suffering from COPD have difficulties breathing, mainly due to the airflow becoming obstructed, persistent production of phlegm and frequent chest infections. 

In animal models, the team found that lung tissues exposed to cigarette smoke and viral infection were less responsive to the drug than tissues those were not.

The research, published in the Portland Press journal Clinical Science, suggests a need for new drugs to treat COPD patients in these categories and a model can be used to test new medications.

"We can then design alternative, more efficacious agents to help treat people with COPD, especially during a viral exacerbation," said lead study author Chantal Donovan from Monash University in Victoria, Australia.