OBJECTIVE To evaluate the efficacy and safety of aclidinium bromide, a novel, long-acting inhaled muscarinic receptor antagonist approved by the Food and Drug Administration (FDA) in July 2012, as a treatment in the management of moderate to severe chronic obstructive pulmonary disease (COPD). DATA SOURCES Literature was identified through PubMed/MEDLINE (2000-March 2013) and International Pharmaceutical Abstracts using the search terms aclidinium, COPD, chronic bronchitis, emphysema, anticholinergic, and muscarinic antagonist. In addition, US government websites, including fda.gov and clinicaltrials.gov , were reviewed for pertinent information. Forest Laboratories, Inc provided previously unpublished clinical trial data. All reference citations from identified publications were reviewed for possible inclusion. STUDY SELECTION AND DATA EXTRACTION All identified Phase 1, 2a, 2b, and 3 studies evaluating the safety and efficacy of aclidinium bromide were reviewed. DATA SYNTHESIS Once- and twice-daily aclidinium bromide was assessed for efficacy and safety in patients with moderate to severe COPD. In comparison to placebo, aclidinium significantly improves trough and peak forced expiratory volume in 1 second (FEV 1 ). Significant increases in trough and peak FEV 1 were sustainable for up to 64 weeks. In addition to improvement in trough and peak FEV 1 , twice-daily aclidinium 400 μg induced clinically meaningful improvements in the health status of patients with moderate to severe COPD. Aclidinium was generally well tolerated, with headache, cough, diarrhea, and nasopharyngitis the most common treatment-related adverse effects noted in clinical trials. Aclidinium did not demonstrate a difference in the incidence of systemic anticholinergic-associated adverse effects in comparison to placebo or active comparator. CONCLUSIONS Aclidinium bromide is a novel, inhaled, long-acting anticholinergic that, when administered at the FDA-approved dose, safely produces clinically and statistically significant bronchodilation and improves health status in patients with moderate to severe COPD. Long-term clinical trials assessing the efficacy and safety of aclidinium are warranted.