Certain lung-disease medications used by millions of people suffering from emphysema and bronchitis may somewhat raise the risk of heart attacks, strokes and even death, according to researchers.

Inhaler drugs help people who encounter problems while breathing by providing them relief. However, the findings of a new study suggest they should be closely monitored, especially those who have both emphysema and chronic bronchitis.

Emphysema is a chronic obstructive pulmonary disease, frequently caused by exposure to toxic chemicals (tobacco smoke counting among them), and bronchitis is an inflammation of the bronchi, a pulmonary disease clinically described as a persistent cough that produces mucus and sputum, for a period of at least three months in two successive years.

A study was carried out to understand the impact of some drugs, Boehringer Ingelheim GmbH and Pfizer Inc.’s Spiriva, on patients with emphysema and chronic bronchitis. Those who took the medicines had a 58% increased risk of heart attacks, strokes or cardiac death than those taking placebo or other medication, researchers found. The findings appeared today in the Journal of the American Medical Association.

“What this means is a reassessment of the cardiovascular safety of these agents is needed,'' Sonal Singh, the study’s lead author and an assistant professor of internal medicine at Wake Forest University in Winston-Salem, said a couple of days ago in a telephone interview. “This study is questioning whether this drug is safe for COPD patients. Regulatory reaction is needed to explain this risk.''

Although the results are considered convincing, several experts claim the research has several limitations. For this reason, one can not be sure if the two medicines are actually responsible for what the study disclosed.

Approved in 2004 by the Food and Drug Administration, Spiriva is a once-daily inhaled maintenance prescription treatment for breathing problems. It has the form of a capsule and contains dry powder, which is inhaled through the mouth by using the HandiHaler device. And Atrovent inhaler is a white to off-white crystalline substance that is used to treat the same lung diseases. Both drugs have been used by an estimated 8 million people worldwide.

Based on a pooled study on 12,500 people, the FDA cautioned patients on Spiriva earlier this year, saying the drug may increase the risk of heart attacks and strokes. Although researchers weren’t able to tell accurately what determined the increased risk of the two, they believe the fact that damaging proteins involved in inflammation are also involved in emphysema, chronic bronchitis and heart diseases.

However, in a statement released by Boehringer and Pfizer, the two companies said the drug they jointly market wasn’t associated with an increased risk of heart attack, stroke or death, based on an analysis of 30 studies involving 19,545 patients taking the drug. "We strongly disagree with the conclusion" of the first study, they said.

With regard to Atrovent, in a Veterans Affairs study the medicine was linked with an increased risk for heart-related deaths in men, The Associated Press reported.