['To compare the efficacy and safety of ipratropium bromide reformulated with the chlorofluorocarbon (CFC)-free propellant hydrofluoroalkane (HFA)-134a (ipratropium bromide HFA) to that of the marketed ipratropium bromide inhalation aerosol (containing CFC) in patients with COPD.', 'This was a randomized, double-blind, parallel-group, placebo-controlled, multicenter trial. The primary efficacy parameter was acute bronchodilator response. The primary end points were peak change in FEV(1) from baseline and area under the response-time curve.', 'Thirty-one clinical centers in the United States participated in this project.', 'A total of 507 patients with moderate-to-severe COPD were randomized, and 444 patients completed the trial.', 'Twelve weeks of treatment four times daily with one of the following: ipratropium bromide HFA, 42 microg; ipratropium bromide HFA, 84 microg; HFA placebo; ipratropium bromide inhalation aerosol, 42 microg; or CFC placebo.', 'Patients in all active treatment groups had significant bronchodilator responses as shown by increases in mean FEV(1) from baseline of at least 15%. Bronchodilator response in all active treatment groups was also significantly more than their respective placebo treatments based on FEV(1), area under the time-response curve from 0 to 6 h, and peak response. FVC results were similar to those seen with FEV(1). There were no significant differences in adverse events, laboratory findings, or ECG findings among the treatment groups.'] Is ipratropium bromide hydrofluoroalkane inhalation aerosol safe and effective in patients with COPD?