NEW YORK (Reuters Health) – The use of inhaled anticholinergic drugs to treat chronic obstructive pulmonary disease (COPD) is associated with an increased risk of developing urinary retention in men, according to a report in the May 23 issue of Archives of Internal Medicine.

In their paper, Dr. Anne Stephenson, with St. Michael’s Hospital, Toronto, Canada, and colleagues point out that the systemic effects of inhaled anticholinergic medications have not been studied extensively. They therefore conducted a nested case-control study to investigate the risk of acute urinary retention with inhaled anticholinergics.

Using population-based linked databases, the team identified 11,238 men and women over 66 years of age with COPD who developed acute urinary retention, and matched them to 55,885 COPD patients without acute urinary retention.

The team found that compared with non-users of inhaled cholinergic agents, men who started using the medications were significantly more likely to experience acute urinary retention (adjusted hazard ratio 1.42) within 30 days of starting treatment. In women, however, the relationship was not statistically significant (adjusted HR 0.71).

Prostatic hypertrophy further increased the risk of acute urinary retention associated with initiation of inhaled anticholinergics (adjusted HR 1.81), according to the report.

The risk of urinary retention was similar with long-acting and short-acting anticholinergics agents, Dr. Stephenson and colleagues note.

“Physicians and the public need to be aware of the potential for this significant adverse event so that preventive measures and potential therapy can be considered,” they advise.

The authors of a related editorial point out that the benefits of inhaled cholinergics are limited. “Therefore, information on serious adverse effects associated with IACs (inhaled anticholinergic medications) can potentially alter their benefit-harm assessment,” they comment.

Physicians should tell patients with COPD about the risks associated with inhaled anticholinergics, they suggest, “and determine the optimal choice of therapy for their patients after eliciting patient preferences for various patient-oriented outcomes in a shared decision-making context.”

Arch Intern Med 2011;171:914-920, 920-922.