MONDAY, May 23 (HealthDay News) -- New research suggests that a certain class of drugs used to treat chronic obstructive pulmonary disease (COPD) boosts the risk that male patients will be unable to urinate.

The disease, which makes breathing difficult due to inflammation and blockage in the body's air passages, affects an estimated 10 percent of people aged 40 and older.

A class of drugs called "inhaled anticholinergic" medications are used to treat the conditions, but there are concerns about their side effects. These drugs include tiotropium (Spiriva), ipratropium bromide (brand name Atrovent) or Combivent, which is ipratropium combined with albuterol.

In the new Canadian study, Dr. Anne Stephenson of St. Michael's Hospital in Toronto and colleagues examined medical records from people in Ontario, aged 66 and older, who suffered from chronic obstructive pulmonary disease.

Of the more than 565,000 patients studied, 9,432 men and 1,806 women developed an inability to urinate. Among men, the researchers found a statistically significant link between those who took the drugs and those who didn't. Among those taking the drugs, the odds of the urinary condition were about 40 percent higher in those who'd been using the drugs for 4 weeks or less, and they were 80 percent higher among those with enlarged prostate glands.

"Physicians should highlight for patients the possible connection between urinary symptoms and inhaled respiratory medication use to ensure that changes in urinary flow (i.e., incomplete voiding, urinary incontinence, and decreased urinary flow) are reported to the physician," the authors wrote.

The researchers added that low doses of the drugs may reduce a patient's risk for these urinary problems.

The study is published in the May 23 issue of the Archives of Internal Medicine.

More information

To find out more about the treatment of COPD, head to the U.S. National Heart, Lung, and Blood Institute.